Anonymized radiation safety deviations

On this page STUK publishes anonymized descriptions of the radiation safety incidents that must be reported without delay, the reasons for them, the resolution of the deviations and the measures to prevent similar deviations. In this way, lessons can be learned from the deviations and hopefully avoid similar incidents in the future.

Radiation safety deviations in health care and veterinary medicine

1

Case 1

A CT scan of the abdominal area was performed on a patient over 70 years old. The instructions were that the imaging would be performed using only contrast medium, but the radiographer inadvertently selected an imaging protocol for the study that included a series of images without contrast medium. The patient received an excess effective dose of 20.2 mSv from the unnecessary imaging. Staff has been reminded to be careful when performing imaging.

Case 2

The cone beam computed tomography (CBCT) machine had been moved to new premises in the hospital and the installer of the machine was carrying out quality control tests with the door open. Two employees in the control room were working on the equipment next door and did not notice the situation. The incident was noticed when the dose meter of the hospital's maintenance supervisor on site alarmed. The workers' estimated effective dose was 0.3 µSv. The radiation safety deviation happened due to the ignorance of the installer. In the following installations and quality measurements, the appropriate operating procedures at the installation site were reviewed together with the equipment installer.

Case 3

In a hospital's positron emission tomography (PET) imaging unit, a patient's PET-TT examination had to be repeated due to a malfunction of the automated syringe. In addition, when the equipment was dismantled, small amounts of radiopharmaceutical solution spilled on the base of the drip stand, on the floor and on the lead-protected container. The contamination was cleaned up as instructed.

The patient received an additional effective dose of about 18 mSv from the study, of which about 2.5 mSv was caused by the administered radiopharmaceutical and about 15.2 mSv by the CT scan performed during the study. For the two radiographers, the excess effective dose from the event was assessed as very low.

The radiation safety anomaly was due to an unexpected equipment failure. The operation of the automated syringe and the operating instructions were immediately checked. In the future, similar radiation safety deviations will be prevented by checking the condition of the equipment and providing additional training on its use.

Case 4

A radiation safety deviation occurred in an animal hospital during a routine X-ray examination due to human error. The exposed workers were an X-ray nurse and a veterinary nurse who were positioning a cat during an X-ray examination. The workers had positioned themselves close to the X-ray tube to calm the cat, which was in an agitated state, when outside the examination room a third person, acting as a help ready to take the X-ray, negligently triggered the x-ray. The radiation exposure of the workers was estimated to be less than 2 µSv.

Case 5

There was a near-miss at a hospital during a gamma scan of a patient's brain receptors. The activity of the iodine-123 radiopharmaceutical, which had arrived in the morning, was incorrectly displayed as too low in the Nuclear Medicine Management Software. As a result, the dosing of the radiopharmaceutical was exceptionally done using an activity meter in the clean room, which showed the correct activity. However, the patient was injected with less radiopharmaceutical than planned, as the radiopharmaceutical injection was remeasured with a faulty meter, contrary to the instructions. However, it was possible to perform the scan as planned, and no re-scan was necessary.

A malfunctioning activity meter in the injection room could have caused false results, which could have resulted in patients receiving wrong amounts of radiopharmaceutical. Based on the hospital's report, the deviation was due to the faulty activity meter displaying incorrect radiopharmaceutical activity, haste, an error in the Nuclear Medicine Management Software and other human error factors. The event was documented, and it was decided that the old meter would be renewed.

Case 6

A technetium-99m contamination occurred in an ultrasound room of a hospital. The radiologist was injecting the patient with radiopharmaceuticals. During the administration of the radiopharmaceutical, the needle became blocked for some reason and an estimated 35 MBq (approx. 0.3 ml) of activity was splashed between the needle and syringe onto the patient, the radiologist, the X-ray nurse, the ultrasound machine, the bed, on the wall and on the floor. Radiation exposure of the radiologist and X-ray nurse was estimated to be less than 3 µSv. To prevent something similar from happening, in the future the force used to press the syringe will be monitored more closely when injecting, and the connection between the needle and the syringe will be checked before administering the radiopharmaceutical.

Case 7

A child came in for an X-ray with her pregnant mother. Only one X-ray nurse was working at the facility at the time of the incident. The nurse held the child during the imaging and the mother of the patient who was being scanned triggered the X-ray machine. The image showed a failed breathing phase, so the image was repeated later that day at a different location. The patient's exposure due to the extra image was estimated to be less than 1 µSv.

The X-ray nurses working in the unit were briefed on what to do in a similar situation. The one involved in the radiation safety incident was verbally reprimanded for action against instructions and a written report of the incident was prepared. In addition, further guidance was given at organizational level on the correct course of action to take in such a situation.

Case 8

Users of an X-ray machine in a hospital noticed an abnormal sound coming from the machine. The discovery was reported to the hospital's own equipment maintenance department, which contacted the equipment supplier. Two service technicians from the equipment supplier inspected the equipment together with the hospital's maintenance staff and the cause of the noise was found to be a malfunctioning collimator. The supplier's maintenance staff found the equipment to be in working order. A dose sampling of the X-ray machine about a month later drew attention to abnormal radiation doses. Quality assurance measurements were carried out on the equipment, which showed that the additional filtering of the equipment was not functioning correctly. However, the device did not report a malfunction of the additional filtering. The device was immediately put out of service.

A total of 600 patients have been imaged between the time the device was serviced and the time the fault was detected. It is impossible to assess with certainty whether the additional filtration was working correctly for an individual patient. The dose to the patient from a conventional X-ray scan varies from patient to patient but is on average small in relation to the potential adverse effects of the radiation. The hospital estimates, based on dose sampling, that patients imaged with defective equipment were exposed to an average dose 140% higher than planned.

The hospital, hospital equipment maintenance and the equipment supplier have addressed the radiation safety deviation and investigated the reasons for the it. The deviation was the result of a malfunction of the radiation equipment, inadequate repair, and failure to ensure that the equipment was in good working order. The root cause was identified as a lack of compliance with the operating instructions and a lack of clarity in the communication and division of responsibilities between the parties involved. As a result of the radiation safety deviation, the operation of the repaired unit will be subject to enhanced monitoring until the original cause of the failure in the operation of the filtration system is identified. As a result of the deviation, the operational guidelines, and the division of responsibilities between operators have also been clarified to prevent similar anomalies from occurring in the future.

Case 9

The iodine-123 injection fluid (37 MBq) ordered for the hospital's department of nuclear medicine was in transit. Early in the morning, a forklift had apparently driven over this shipment of injection fluid. As the assessment of the fire brigade was that no leakage was visible, it was decided to transport the broken shipment, wrapped in a double plastic bag, to the hospital's department of nuclear medicine for ageing. In the department, it was found that the ampoule of injection fluid was intact, although the shipping carton and the protective container were badly damaged. No contamination was found in the package, the protective container or the packaging materials of the shipment. The iodine-123 injection fluid in question was aged in the waste storage facility of the department of nuclear medicine.
This was a near miss. No radioactive substances were released into the environment.

Negligence in the handling of the radioactive consignment was assessed as the cause. The transport operator should review the incident and the reasons that led to it internally with their safety advisor. Radioactive sources are usually quite well packed and in this case the packaging protected against contamination. However, looking at the packaging, the ampoule would probably not have survived intact if the forklift had driven completely over the metal container. Such a possibility should already be considered when packing the consignment. Finnish Safety and Chemicals Agency (Tukes) is handling the accident report related to this radiation safety deviation.

Case 10

Due to temporary malfunctions of the positron emission tomography/computed tomography (PET/TT) machine, two patients failed to be imaged. Re-imaging could not be performed immediately because the camera took so long to recover that the activity of the radioactive drug the patient had received had been reduced by half to too low a level. Furthermore, the corrective measures taken after the first malfunction did not allow the assumption that the failure would occur again within the same day.

Both patients had had time to have a CT scan taken during the study, so the additional radiation exposure consists of the CT scan plus the injected fluorine-18-FDG. This radiation safety deviation resulted in excess radiation exposures of 10.9 mSv and 11.5 mSv for the patients.

The cause of the radiation safety deviation was a technical malfunction of the equipment, which may have been related to a thunderstorm the previous day. The equipment manufacturer will ensure the condition of the equipment and carry out maintenance. The radiation safety deviation will be discussed in a team meeting and in the quality working group to avoid similar incidents in the future. An incident report has been submitted to Finnish Medicines Agency (Fimea).

Case 11

One nurse had already turned on the radiation therapy unit's computed tomography simulator (CT simulator) for the morning heating, while another nurse went to turn on the DIBH machine (a device to ensure that radiation therapy is given at the phase of breathing). The nurse did mention turning on the heating, but the DIBH machine had not started the first time, so the second nurse inadvertently went to turn it on again. The morning heating of the CT machine started while the nurse was in the side room turning on the DIBH machine - not actually in the imaging room. The door to the control room was also open while the machine was on, so the other nurse in the control room must also have had a small additional radiation exposure. The CT simulator alarmed twice before the nurse noticed the situation and interrupted the radiation.

The nurses have personal dosimeters. The dosimeters were read after the event. The nurse in the side room had a deep dose reading of 1 µSv and the nurse in the control room had a deep dose reading of 3 µSv. Both had a surface dose reading of 0.00 mSv.

The situation was reviewed, and the exposures were assessed with those involved and discussed in a joint unit meeting. The situation was caused by human error and an unexpected situation. In the future, people are reminded to check that the CT is not on when entering the filming room. The instructions will be revised to ensure that when filming or testing on the machine, the operator is at the control machine, so that he or she is able to stop the irradiation as quickly as possible in the event of an unexpected situation.

Case 12

In a hospital, a wrong patient was referred for CT scans of the body, as a result of which the patient was exposed to extra radiation. A radiologist and an X-ray nurse had checked the referral. The patient was exposed to a radiation dose of 12.07 mSv.

After the incident, an immediate investigation was launched to determine the causes of the situation. The incident was due to carelessness when writing the referral and the referral was not reviewed critically enough before the imaging was started. The staff was reminded to verify unclear referrals in the future.

Case 13

A patient underwent a lung X-ray while being in a hospital ward. The X-ray was taken at a higher current than planned. This was due to an input from the touch screen, probably caused by a drop of liquid on the touch screen or other similar incorrect contact. The patient received an additional exposure, which was estimated to be 1.8 mSv.

The device manufacturer, together with the hospital, has launched an investigation into the causes of the deviation. The hospital is also clarifying its operating instructions and requiring the person taking the X-ray to verify imaging settings just before taking the image. The radiation safety deviation is reviewed in the unit and, where applicable, also in other units.

Case 14

A patient had an anaphylactic reaction to a contrast agent during a combined computed tomography/positron emission tomography examination. The patient contaminated the PET table with his urine. The PET room was thoroughly cleaned, and contamination measurements were taken before continuing operations. The incident resulted in minor additional exposure to the staff involved in the management of the event. They received an expert estimate of a dose of 3 µSv. The patient did not receive an additional dose.

The incident has been dealt with internally in the hospital and it has been concluded that these types of incidents are not completely preventable as the cause is patient induced. The department has guidelines for dealing with both contamination and resuscitation situations. Both situations have been rehearsed, but no provision was made for them to occur at the same time. Following the incident, several changes were made to the instructions to improve the department's preparedness for a similar event in the future.

Case 15

At the hospital, after an interventional CT procedure, it was discovered that the doctor's radiation shield was unusable (lead had drifted to the bottom). The lead apron had been checked in the spring of 2022 with fluoroscopy and was intact at that time. 

The doctor performed at least two CT procedures with it, the movable radiation shield he was only able to use partially because the procedures were challenging. It may be that he had used this apron before, but the dosimeter had not received a dose. The doctor received a small excess dose of radiation (effective dose estimated by measurements to be no more than 0.35 mSv). The radiation protection apron was taken out of service and the purchase of a new one was initiated. The quality control of lead aprons is being improved in the hospital.

Case 16

Two radiation safety deviations occurred at a veterinary clinic within a short period of time. The first radiation safety deviation occurred when a pregnant employee entered the imaging room while an X-ray was in progress. However, she remained more than two metres away from the X-ray machine.

In the second case, a customer under the age of 18 took part in the radiography by holding the animal in the right position. The customer's age was verified before the radiography by asking if he was at least 18 years old, to which he had answered affirmatively. The client was in fact 15 years old. He wore a lead apron and a thyroid shield during the radiography and was not directly exposed to primary radiation. The additional radiation exposure of the employee and a member of the general population under the age of 18 was estimated to be less than1 µSv in both cases.

Case 17

At a hazardous waste treatment plant, a waste container from a hospital was found to be radiating. In the measurements, the radionuclide was identified as iodine-131 and its activity was approximately 5 MBq, which exceeded the free limit set for that iodine isotope, meaning that the waste could not be burned immediately. The container was left at the waste treatment plant to wait for decay until burning is allowed. 

No one is known to have been exposed to radiation because of the deviation. The radiation safety deviation was caused by carelessness in measuring the waste in the hospital's isolation room. In the future, a separate room for iodine-131 waste will be built in the hospital's half-life storage, where waste from the isolation room will always be brought to decay. When removing garbage, its dose rate is measured, and it is ensured that it does not exceed the limit values.

2

Case 1

An x-ray was being taken of the patient’s lungs. When the radiographers came from the imaging room back to the control booth, the patient transporter triggered the imaging with the intention of helping. The situation did not result in any additional radiation exposure for the workers, and the imaging of the patient was technically successful.

Incorrect operation of the patient transporter was discussed internally with the persons responsible for patient transport and in the x-ray department meeting. The undertaking submitted a radiation deviation report and a patient safety report on the matter.

Case 2

A hospital orderly received a radiation-emitting item (technetium generator), although the orderly does not have the rights to do so. Only the personnel of the nuclear medicine unit may receive items containing radioactive materials. Fortunately, the generator was left in a locked room in the isotope laboratory, so there was no danger.

Similar incidents are prevented by re-training hospital orderlies. The transport company was contacted and it was discussed with them who can receive a parcel. Written instructions on the delivery and reception of parcels are drawn up for the door of the nuclear medicine unit. In addition, the hospital security manager is contacted about the fact that the hospital orderly has allowed an external person to enter the premises of the nuclear medicine unit while the unit is closed.

Case 3

The patient was undergoing full-body (head-to-toe) PET/CT imaging. The equipment's imaging data collection computer went into a fault state in the middle of the patient's imaging, and the imaging had to be interrupted.

The PET imaging nurse informed the physicist and maintenance was requested. The equipment maintenance personnel ran the entire equipment down. This takes a long time, so the patient could not be imaged again as the delay in the schedule would also have prevented the next four patients from being imaged. After the PET/CT equipment was ran down, the equipment functioned normally and other patients were imaged on schedule. The physicist and the radiographer tried to make images of the data afterwards, but the only the head area data was stored, so the nuclear medicine physician ordered the patient to be imaged again.

The reason for the radiation safety deviation was the failure of the PET imaging data collection computer. Due to the fault, the patient's imaging had to be repeated and the patient received an additional effective dose of 10.5 mSv. After the incident, the unit contacted the equipment manufacturer through the hospital's equipment maintenance, where the deviation is being investigated. If a fault is detected in the computer, the equipment manufacturer will repair it as warranty service.

Case 4

A planning image of the patient’s spine and pelvic region was requested for radiotherapy dose planning, and the patient was imaged in a CT simulator in accordance with this request. After the imaging, it was revealed during the interview that the patient had received radiotherapy in another hospital two months earlier. The patient's texts or information from another hospital did not mention the radiotherapy received. After the imaging, the radiotherapist was informed of the patient having received radiotherapy in another hospital. The physician promised to look into the matter. According to the clarification, the patient had received radiotherapy for the same areas where it was planned to be given in the patient’s own hospital. The patient accumulated additional radiation dose corresponding to the planning image (effective dose 31.5 mSv). The planned radiotherapy was cancelled and a deviation report was submitted.

The reasons for the incident were the interruption in the exchange of information and possible misunderstandings along the patient's abnormal treatment path. The patient had an abnormal treatment path as the patient was treated in another hospital due to a drug trial. At the patient’s own hospital, it was not known that the patient had received radiotherapy elsewhere. Before the dose planning imaging, no indication on the patient having already received treatment was noticed. From the point of view of initiating radiotherapy, a near miss situation arose in this case. 

The deviation report was discussed at an internal meeting of the radiotherapy unit. It was noted at the meeting that questions about old treatments must be asked at the physician's appointment and during interviews in connection with the planning imaging. As an additional measure, it was checked that the patient's interview form contains a section asking about previous treatments. This will ensure that the matter will be clarified at least at that point of the patient's treatment path. 

In the future, the workflow will be modified so that in contrast medium imaging previous treatments are asked at the same time when it is asked whether the patient has reacted to the use of contrast medium previously. In similar cases, this would also avoid exposure to unnecessary CT imaging. In addition to the in-house processing of the matter, the adverse event was also reported to the Quality Manager of the other hospital. This Quality Manager processed the matter according to the unit's own practices.

Case 5

During the hospital's evening shift, a small child had come for an x-ray examination of the abdominal area with her pregnant mother. However, the child did not stay still for the examination, so the two radiographers held the child in the correct position during the examination. Since there were only two radiographers on duty, the patient's mother triggered the imaging under the instructions. The next day, the radiographers realized that they had made a mistake. However, there was no additional exposure caused by the deviation, as the patient's comforter was in a different room during the imaging and the radiographers wore radiation shields. 

The deviation was discussed with the radiographers and at the unit meeting. The reasons for the situation were hurry and the change of shift. For the future, the personnel will be informed of practices related to radiation safety so that a similar situation does not occur.

Case 6

The patient underwent a skeletal scintigraphy with a radiopharmaceutical preparation. After the imaging, the activity was approximately 447 MBq, of which approximately 152 MBq was excreted in urine. The patient's urinary catheter bag was emptied prior to the imaging by the patient or the patient’s relative, and the drainage valve at the bottom of the bag was left open. After the examination, the nurse went to help the patient to get up from the examination table and lifted the urinary catheter bag, whereby radiant urine flew onto the nurse’s pants (approximately 2.9–3.5 MBq) and socks (approximately 1.0–1.6 MBq). The nurse took a shower and changed the clothes. The nurse was exposed to a small amount of additional radiation.

The examination table area was cleaned. At the front of the nurse's pants, there was an approximately palm-sized spot of urine. The radiation of the trousers was 5 µSv/h measured at a distance of 10 centimetres. The radiation of the sock was 2 µSv/h. The nurse was exposed to the radiation for approximately 15 minutes until the nurse took a shower and changed the clothes. After the shower, there was no noticeable radiation on the skin. Radiation waste and radiating clothing were placed in a lead-lined container and treated in the usual way after the half-life. The effective dose of the nurse, even when well overestimated, was no more than 2 µSv, which corresponds to 3–12 hours of background radiation. 

In the future, everyone emptying a urinary catheter bag must remember to carefully close the drainage valve. The induction instruction is supplemented with a statement that the position of the urinary catheter bag valve is checked before moving the bag.

Case 7

The radiographer went to the imaging room after the CT scout view to calm down a patient suffering from claustrophobia. The radiographer taking the image did not check the situation in the imaging room, but started the imaging while the colleague was still in the imaging room and the door was open. The radiographer taking the image noticed the situation immediately and interrupted the imaging. The equipment was able to take approximately 5 cross-sectional images. There were no people near the door. When the colleague left the imaging room and the door was closed, the imaging was normally continued and completed. The patient did not receive any additional radiation. 

The radiographer was exposed to an effective dose of up to 13 µSv. The cause of the deviation was the stressful situation, hurry and a general chaos. The patient was afraid and the patient’s speech was difficult to understand, so the nurse had exceptionally gone to the imaging room to calm the patient down while the actual imaging was planned. There was a lack of communication between the colleagues.

Case 8

The patient was ordered two CT scans: periradicular infiltration and lumbar spine CT. Lumbar spine CT was supposed to be taken after the periradicular infiltration, but a confusion in secretarial work and possibly a communication problem between computer systems led to a situation in which the lumbar spine CT was taken at the time reserved for the periradicular infiltration. The referral seen by the radiographer on the CT scanner had not given reason to doubt the timing of the examination, and the radiographer performed the examination normally.

Later, the radiographer who was taking the CT scan had heard that the case was being investigated at the x-ray unit. As a result, the radiographer made an internal radiation safety deviation report, which brought the case to the attention of the Radiation Safety officer. The patient is estimated to have received approximately 19 mSv of additional radiation exposure.

The matter was discussed with the secretary who handled the patient's examination appointments. The secretary was reminded of the correct procedure if there is any ambiguity in the appointment of the patient's examinations between different information systems. The case has been reported to the immediate supervisor of the secretaries and the supervisor has been asked to review what has happened and to go through the correct operating methods when booking appointments together with the secretaries who book appointments. The patient has been informed of being subjected to an unnecessary examination. The patient has been rescheduled for periradicular infiltration.

Case 9

In the radiology unit of the hospital, a radiation safety deviation occurred in the health care CT scan. The radiographer chose a native imaging program even though the imaging was requested with contrast medium. Due to incorrect selection of the imaging program, the images had to be re-taken. As a result of the re-scan, the patient received an additional exposure of approximately 16.4 mSv. 

The situation was addressed through interviews with employees about the reasons for the deviation. The deviation was due to human error and lack of communication at the workstation. The incident was discussed with the radiographer. In the future, communication will be improved so that similar situations can be prevented.

Case 10

During the patient's CT scan in the radiology unit, the patient was exposed to a larger amount of radiation than planned as the wrong imaging program was selected. The radiographer chose the wrong imaging program which had three phases, of which only one was necessary. The effective dose due to unplanned medical exposure to the patient was 12.2 mSv.

The reasons for the deviation were discussed with the employee involved in the situation. A human error occurred in the selection of the imaging program. The incident was discussed with the radiographer who performed the imaging, and the unit emphasizes the importance of finding out the correct imaging program also during on-call times in the future.

Case 11

A patient undergoing two-field palliative radiotherapy (pelvis + thigh) received an additional dose of approximately 1 Gy for the other field (pelvis) during the first treatment. This was due to confusion about taking pre-treatment check-up images between the radiographer manually positioning the patient and the other who performs the treatment.

A patient safety incident report was prepared at the hospital and the importance of check-up images after manual transfers has been discussed with the employees. The patient and the patient's relatives were informed of what had happened and the extra dose for the first treatment was taken into account during the second treatment. The total dose received by the patient was not exceeded.

Case 12

The patient received radiotherapy for a benign tumour in the brain region. The patient had their last confirmed menstrual period about two weeks before the radiation oncologist's appointment. At that time, the patient had been instructed not to attempt to become pregnant during radiotherapy and to start contraception. The patient had followed these instructions since that day.

Immediately after radiotherapy (2.5 weeks after the appointment with the radiation oncologist), the patient reported that she was pregnant. The hospital immediately carried out a uterine dose estimate based on the patient's radiotherapy plan. The result of this measurement was 25 mGy for the entire radiotherapy period.

An embryonic exposure assessment was performed for the patient receiving radiotherapy and it was reported that, at this exposure level, the risk to the developing child from radiation is negligible. The patient confirmed that she remembered the doctor's instructions on how to avoid becoming pregnant during radiotherapy. A pregnancy test taken at the beginning of the radiotherapy period would probably not have revealed the pregnancy that had just begun. 

Case 13

The nurse went to medicate a patient during a procedure without personal radiation shields. X-ray images were taken during the procedure when the nurse was next to the patient. The nurse was in the imaging room for about 8 seconds, of which about 5 seconds the nurse was next to the patient. The dose estimate was calculated to be less than 2 µSv. The incident was due to negligence and the employee was unable to provide an explanation for what happened.

Case 14

At the hospital, a CT-examination of the patient's body was carried out. After the scan, the device did not reconstruct the images and the patient had to be scanned again with another CT device in the hospital. The additional scan caused an effective dose of approximately 21 mSv to the patient. The equipment supplier was contacted about the incident, and it turned out that the image reconstrction hardware on the device was broken and the reconstruction of the images was therefore unsuccessful. A radiation safety deviation was reported in accordance with the hospital's instructions and the incident was processed in the unit.  

Case 15

The patient underwent a CT scan intended for another patient (a dual-phase liver scan and follow-up scans). Two patients had almost identical last names, and the patient had not been identified prior to the scan in accordance with the instructions.

The patient received a radiation dose of about 15.5 mSv from the unnecessary examination. The incident was discussed in the operator's department meeting, and the personnel was reminded of the patient identification procedures.

Case 16

The control panel frame of the intraoral x-ray device was broken and the button for subjecting to radiation was pressed to the bottom. As a result, the x-ray equipment started taking images of itself as soon as the equipment was switched on. This happened four times before the personnel realized what was going on. After this, the use of the x-ray equipment was discontinued.

The incident caused additional exposure to the dentist, as the dentist's feet were exposed twice to a direct radiation beam. The patient in the treatment room was also exposed to scattered radiation. The radiation dose to the dentist was estimated to be less than 0.02 mSv. The maintenance service replaced the broken part of the x-ray equipment, and the operating condition of the equipment was checked before commissioning. The notifier has also made an incident report to Fimea.

In order to prevent similar incidents in the future, the matter was handled internally and the mechanical testing of the equipment is part of quality assurance before treatment.

Case 17

A pregnant patient underwent an abdominal CT-examination. At first, attempts were made to MRI scan the patient, but the first images showed artifacts probably due to explosive fragments. After the first imaging attempt, the patient was assessed to be incompatible with the MRI scan. However, in a later review, an MRI examination was considered possible. The estimated radiation dose to the foetus was 13.5 mSv.

As a result of the incident, employees were interviewed for reasons that led to the deviation. The radiation safety deviation was caused by problems in the information exchange between the imaging unit and the units treating the patient. In order to prevent similar situations in the future, the patient's magnetic compatibility assessment process and its information flow, especially during on-call examinations, are monitored. Necessary changes will also be made to prevent gaps in the flow of information.

Case 18

In the hospital, the patient was scanned twice with CT equipment as, during the first scan, the contrast media tube was accidently not attached to the cannula and the scan was performed without contrast media. The patient received an additional radiation dose of approximately 12.5 mSv.

The human error of the nurse was discussed with the personnel at the department meeting, and the employees were reminded to pay attention to the preparation of the patient even in the middle of busy times.

Case 19

In the radiotherapy unit, the patient was prescribed radiotherapy on pain in three different metastases. One of the targets was a metastasis on the femur. However, the target area of the femur was segmented on the wrong leg. The target in question was prescribed radiotherapy with fractionation of 5*4 Gy. The treatment plan in question reached the implementation stage for the first two fractions before it was discovered that the treatment was drawn on and targeted at the wrong leg. As a result, this healthy femoral section was treated with 2*4 Gy in consecutive days. The treatment plan was rapid pain management of two opposing fields. In addition to the femur, the tissues in this treatment area are mainly muscles, fat, lymph nodes and skin.

Upon detection of the error, the situation was immediately assessed by a multi-professional team. The physician who treated the patient reviewed the case with the patient, and a more detailed investigation of the case was initiated within the hospital. On the basis of the initial evaluation, the physicians started monitoring for any immediate side effects (such as redness or swelling of the skin). The risk of long-term adverse effects in this case was estimated to be extremely low. According to the chief physician of radiotherapy, it is likely that the patient will not suffer significant adverse effects due to the treatment error, taking into account the patient's advanced age, the spread of the cancer and the nature of the disease. Considering the dose received and the small treatment target, acute adverse reactions such as lymphoedema and anaemia are unlikely. 

According to a more detailed study carried out by the hospital, the radiation oncologist had used diagnostic CT scans in drawing the treatment targets. In the CT simulation image used for radiotherapy planning, the patient was imaged in a different position compared to diagnostic CT scans due to the feasibility of radiotherapy. When the physician had drawn the target area on the CT simulation image, the physician had accidently drawn it on the wrong leg. The physicists performed treatment planning on a CT simulation image drawn by the doctor. This is why the plan was made for the wrong thigh. Eventually, the physician approved the plan for treatment, and the radiographers began radiotherapy as planned. The radiographers and physicists noticed the target on the wrong thigh when they looked at the entries after the second fraction. 

In order to prevent similar cases, the clinic physicians were reminded that the CT simulation image is always the official planning image for radiotherapy. Even if the physician uses other images, it should always be ensured that the radiotherapy target is correctly drawn on the CT simulation image. After the incident, different treatment positions and how they should be recorded in the systems were reviewed with all occupational groups. In addition, the review of the different stages of the radiotherapy chain (within the professional groups as well as in terms of the performers of the next stage) and the possibility for the physician to check that the treatment plan and the target are correct and optimal at the time of approval of the treatment were also reviewed.

Case 20

A 1.1 GBq capsule of radioactive iodine was ordered for the hospital's radiotherapy unit. The employee of the transport company who brought the shipment left the package in the waiting room chair of the radiotherapy unit while the employee left to look for the receiver of the shipment. The hospital had given the delivery service provider the orderer's telephone number and instructed them to call if the recipient was not present at the time of delivery. For some reason, however, the courier left the package unattended in the waiting room instead of calling the recipient to come and pick it up. 

The near miss situation did not cause any additional exposure to the employees or the population, as the source was properly packaged. In order to prevent similar incidents, the hospital made a complaint to the transport company and instructed the driver in the correct procedure.

Case 21

A radiographer student entered the CT scan room during the heating and calibration of the equipment. The student stayed in the room for approximately 20 seconds. The incident was due to human error, as the student had received a normal orientation to the use of the equipment. The effective dose caused to the student by the incident was estimated to be less than 0.04 mSv. In the future, the hospital will provide more information about radiation during heating and calibration in the imaging room.

Case 22

The patient underwent a CT scan of the heart and aorta. During the examination, the radiographers inadvertently placed the scout image tracking the contrast medium and starting the scan in an anatomically inappropriate place, due to which the contrast medium administration was not sufficient during the scan.

Due to this error, the examination had to be repeated under the guidance of a radiologist. Due to the re-scan, the patient received an additional effective dose of 12.3 mSv. The instructions will be specified to make the selection of the scout image clearer, and it will also be verified from the radiologist, if necessary.

Case 23

An extensive CT scan of the body with contrast medium was performed on the patient. After the scan, the radiographers noticed that the contrast media tube had leaked from the connection point of the tubes during the scan and some of the contrast medium had spilled on the floor. The radiologist looked at the images and estimated that the contrast enhancement was not sufficient, so the scan had to be repeated. The patient received an additional effective dose of 20.6 mSv.

The reason for the incident remained unclear. The contrast media tube was not saved, and it is not clear whether the contrast media tube was poorly attached or if there was something wrong with the tube. The employees were instructed to assemble the contrast media tubing more carefully and, in the event of an abnormal event, to save the equipment for possible further investigation.

Case 24

The patient had heavy nose bleeds. The referring medical practitioner had asked that the patient’s artery on the left side of the patient’s nose be occluded under fluoroscopic guidance. However, the operation was inadvertently carried out on the right side. Bleeding continued and the patient’s left nasal artery still had to be cauterized under general anesthesia. The scanning operation was unnecessary and the patient was exposed to an additional radiation exposure of about 19 mSv.

The case was handled together with the angiography team and it was considered how to ensure the correctness of the procedure to be performed in the future. In the future, the importance of familiarizing with the referral for the entire team participating in the operation will be specified and it will be adopted as a practice that the consulting radiologist arriving at the site will make sure that the preliminary data is correct.

Case 25

The hospital's computed tomography equipment did not complete the patient's heart CT scan. During the scan, there were no error messages of any kind, and no error messages were found in the device's log data either. On the day before the scan, an attempt had been made by the service workers to replace a part that had previously caused interference in the motion of the scanner table. However, the servicing work could not be completed due to the lack of a spare part. Therefore, the hospital's initial assessment of the cause of the deviation was a device failure.

The hospital reported the deviation to the device supplier, but the device supplier did not find any signs of a device fault in the device's log data. Therefore, the actual cause of the deviation remained unclear. One possible reason could be a human error in the delimitation of the imaging area, as the patient suffered from morbid obesity and their heart had been anatomically abnormally low. The patient was exposed to an additional radiation exposure of about 13 mSv. The guidelines for CT scans for morbidly obese patients were changed. In addition, the potentially defective part of the imaging table will be replaced.


Case 26

The patient had been prescribed an elbow CT-examination. The elbow was in a plaster cast at an angle, which meant that the scan could only be taken with the hand next to the body. The patient was large, so getting the elbow into the imaging field was challenging. After the imaging, it was noticed that the elbow had not been fully imaged, so the imaging had to be repeated. The patient received an additional dose of approximately 20.8 mSv.

The case was discussed with the workers and the emphasis was placed on due diligence in the case of such patients. In similar situations, the location of the scanned area must be ensured.

Case 27

The patient underwent an adrenal CT scan. The radiologist gave instructions to first take a series of images without contrast medium, after which the need for taking a possible series with contrast medium would be decided. The examination was started in accordance with the instructions, and the radiologist was asked after the first series of images about the need for the use of contrast medium. The radiologist advised that the examination is carried out with a series of contrast medium images. 

The first series of images taken of the patient was automatically sent for analysis immediately after the series was taken. Before the contrast imaging, it was noticed that this first examination had already been analyzed by another radiologist. The radiographers called the radiologist in question, who stated that a series using contrast medium would not have been needed, as it was possible to make the diagnosis from the first series of images. The patient thus unnecessarily received contrast medium and an additional effective dose of about 16 mSv.

On the basis of a report by the Radiation Safety Officer, the case was a borderline case in which contrast imaging would also have been justifiable. In addition, the radiologist had later made an incidental discovery from the series of contrast images. Radiologists were instructed in similar cases to communicate more clearly with each other in the future so that they could decide on further measures together.

Case 28

The normal X-ray functionality of the portable X-ray device used as a backup in operating rooms had malfunctioned, and the radiation beam collimators were also not functioning. A different imaging program was used, resulting in slightly higher patient doses than usual. Approximately one or two patients received over 50% higher exposure than normal. The doctors using the equipment did not have sufficient information about the dosage levels for different imaging programs, and information about the faulty device did not reach the hospital physicists. When the issue was discovered, the backup device was immediately taken out of use and will be permanently retired.

Case 29

Several patients had registered for a CT scan. One patient was inadequately identified before the procedure, and a lumbar spine CT examination was mistakenly performed on the wrong patient. The error was discovered shortly after the examination, and the patient was scheduled for the correct head CT scan. Since the examination was not urgent, there was no delay in the patient's care.

According to the hospital physicist, the elderly patient received an additional effective dose of 11 mSv due to the mistake. The incident resulted from human error and will be addressed internally at a department meeting. In the future, more attention will be paid to adhering to patient identification guidelines.

Case 30

A two-phase lung contrast-enhanced CT scan was planned for a patient. After the examination, the radiologist reviewed the images and found that the contrast enhancement was insufficient, requiring a repeat scan. This led to an additional radiation exposure of approximately 13.6 mSv for the patient. The cause of the deviation remained unclear since the contrast delivery system had functioned normally during pre-examination testing. The incident was discussed within the unit, but no corrective actions could be taken without identified reasons for the error.

Case 31

A patient was scheduled for external radiation therapy with three separate dose plans. Due to a human error, the patient received treatment according to two different dose plans during the first five treatment sessions (double dosage). The patient received one more treatment according to the first dose plan before the error was detected, and treatment was suspended for a week. According to the doctor, the patient did not experience any adverse effects due to the treatment. The treatment was supplemented with additional doses so that the treated areas received a biological dose equivalent to the original dose plan. In the future, two physicists will closely review the timing of dose plans.

Case 32

A CT scan for lung embolism and abdominal contrast was performed using an emergency department CT device. During the contrast injection, the contrast delivery tube became detached from the three-way valve on the contrast injection side. It was noticed during the scan that the contrast agent was not where it should be, necessitating a repeat of the examination. The patient received an additional effective radiation dose of approximately 14 mSv due to this.

Case 33

The PET/CT device experienced a malfunction, leading to the interruption of the scan for both the CT and PET components. The CT scan had to be repeated several times due to the interruptions, and the PET scan was initiated twice before the device stopped responding completely. Two other patients had already been injected with FDG contrast agent before the equipment failure was identified.

The radiation safety deviation resulted from a technical malfunction of the equipment. The calculated additional effective doses for the patients were 14 mSv, 5.8 mSv, and 6.3 mSv.

Medical equipment maintenance staff were called in immediately for repairs and to verify the camera's functionality. A report was sent to the equipment manufacturer, and the repair was ordered with spare parts. Other examinations were canceled and rescheduled for a later time. The incident was discussed internally at a team meeting, and a report of the incident was submitted to Fimea.

Case 34

The doctor ordered a CT urography and the patient was given an appointment for an imaging scan in a few months' time. The same patient went to the hospital with acute pain two days before the scheduled imaging and the doctor referred him for a CT scan of the urinary tract. The radiologist converted this outpatient examination into a CT urography and the patient was imaged on the same day. The outpatient examination did not cancel the earlier referral for a CT urography and the patient was imaged according to the original referral a few days later at another hospital. The latter imaging was practically unnecessary, as the situation had not changed in two days.

The latter CT scan resulted in an effective dose of about 38 mSv to the patient. The radiologist who performed the second scan reported the anomaly and the anomaly was discussed by the hospital's quality team and between the CT process owner and the physicist in charge.

The latter imaging could have been avoided by cancelling its referral. However, the hospital's current information system did not have a clear function for this, nor guidance for staff. In the old information system, the examination could be "tied", so that it did not appear on the patient's examination list, but did not disappear completely. This is now being taken forward in the organisation with the aim of providing guidance on deletion and the hope that the information system will also be improved.

Case 35

In the hospital's radiation therapy unit, a malfunction occurred with the afterloading device for internal radiation therapy, when the patient was given multi-channel therapy to the prostate. The treatment had to be interrupted with the interrupt button. In this situation, after interrupting the treatment with the interrupt button, the device's notification of treated channels was relied upon. Due to the response delay (50 ms) of the device control system, the treatment of the pre-interrupt channel was not registered. As a result, one of the channels was treated twice. The treatment machine therefore displayed the treated canals incorrectly.
The contribution of one channel did not significantly increase the patient's total dose.

Licensees using similar devices have been informed about the malfunction. The device supplier has promised to fix the software error in the next software version. The unit has implemented a more accurate method for monitoring the progress of the treatment (the treated channels are recorded manually during the treatment) and instructions are given to make a non-urgent interruption of the treatment with the interrupt button only after the source has reached the protected position.

Case 36

The CT scan had to be completely repeated due to a ruptured vein during the administration of the contrast agent. The patient received an excess dose of approx. 15 mSv from the renewed examination.

Case 37

The patient had an X-ray taken earlier that day in a private medical care unit. The images were requested to be transferred to a public hospital, but according to the X-ray nurse of the private medical care unit, the images remained in the image archive in "pending" status and were not transferred.

The X-ray nurse also called the image archive support at her own hospital, where the problem was not detected after checking their systems. However, during the call it became clear that there had been similar problems in the recent past with archiving and transferring images between imaging units.

The issue was discussed with the patient and, with his consent, the imaging was re-done. This was a relatively low-dose study.

The root cause of the problem is thought to be a broken or unstable data link between the archives. At the time of notification, the images of six patients were in the "pending" status in the private provider's archive. This potentially causes additional radiation exposure to patients when they are re-imaged due to the failure of the archive.

Case 38

A radiation safety deviation occurred in the radiotherapy department during the performance of quality assurance tests for dose planning CT. The CT device reported in the middle of the quality control tests that one test failed due to incorrect positioning of the phantom. The device requested to reposition the phantom, so two nurses entered the imaging room to check the position of the phantom. Neither of the nurses touched the imaging device or the adjustment mode buttons, but both the CT device and the imaging console briefly lit a radiation warning light. The nurses noticed the light and quickly left the imaging room.

Later, an attempt was made to repeat the situation, but it was unsuccessful. The radiation therapy physicist visited the site to assess the situation. The situation and exposure assessment were immediately discussed with the nurses involved in the incident.

The radiation safety deviation was cause by a human error and an unexpected situation when the phantom's positioning was being checked. The incident has been discussed in the departmental meeting for the nursing staff and in the quality meeting for the entire staff. The quality control guidelines have been revised to emphasize that no one should enter the room during ongoing quality control protocol. Additionally, a radiation interrupt switch will be installed on the door of the CT imaging room.

The estimated doses for the two X-ray nurses were below 10 µSv.

Case 39

A radiation safety deviation occurred in the X-ray department of a hospital, where a patient was overexposed to radiation during a CT scan and the effective dose exceeded 10 mSv. The patient kept his hand in a hook during the examination, although the nursing staff had instructed him not to do this. The contrast agent tube attached to the hand came off during the examination and too little of the contrast agent was released into the bloodstream. However, the examination was completed. The patient had to be reimaged as a result of the incident, as the previous attempt had not provided enough contrast agent and the images were undiagnostic.                     

The radiation safety deviation was due to unforeseen reasons. As a result of the incident, the patient had to be re-examined. To prevent similar events, the medical staff checks before the examination that the vein is open and that the pressure in the intravenous drip is not increasing too much.

Case 40

During a cardiological CT scan, for some reason the shadowing set had been incorrectly set so that the shadowing injection did not start during the scan. So the imaging was done without the contrast agent in native mode, which was an unnecessary imaging.  The imaged patient received an additional effective radiation dose of 16 mSv.

Case 41

In interventional radiology, a new angiography device was tested twice using the factory settings for CT contrast imaging. Both imaging series were inadequate for diagnosis. The patient received an additional effective radiation dose estimated at 13 mSv. The CT protocol with the factory settings was modified after the incident.

Case 42

During a radiological procedure in an emergency situation, the anaesthetist entered the room without proper radiation protection, contrary to the instructions. As soon as this was noticed, the device's ability to produce radiation was immediately cut off. It is not entirely certain whether radiation was used during the time the anaesthetist was in the room without radiation protection, but at most the radiation was on for a few seconds. The maximum dose to the anaesthetist was about 60 nSv. He possibly assumed that in the event of an emergency it was possible to enter the room without radiation shields. He had not participated in the regular CPR simulation in the procedure room.

Case 43

The radiographer had loaded the contrast agent syringe and the saline syringe incorrectly into the device. The contrast agent syringe was on the saline side and the saline syringe was on the contrast agent side. Based on the physicist's assessment, the patient received an additional effective dose of 10.9 mSv. A Haipro report has been filed regarding the incident caused by a human error, and it has been discussed at a department meeting. Particular carefulness will be taken in the future.

Case 44

A large pneumothorax was found during a lung biopsy. An attempt with a CT scanner was made to check the position of the drain placed to treat the pneumothorax, but the CT scanner did not respond to pressing the imaging pedal. The scan was successful only after restarting the procedure program. However, it was later discovered that the CT equipment had been exposing the patient to radiation even when it did not appear to respond to pressing the imaging pedal. This resulted in a small additional radiation dose for the patient. Additionally, the radiologist who performed the procedure also received a small additional radiation dose.

The situation was reported to the equipment supplier. According to the supplier, the procedure cannot be continued using the control panel located in the CT equipment's procedure room as described by the users. The device displays a warning about this, but the procedure can still be continued. In this case, the images are saved but can only be viewed in the control room. The supplier claims that the device is functioning correctly, although the operating style is not intuitive for the users.

In similar situations, the equipment supplier advised to always start a completely new procedure to avoid encountering this problem. This has been the case at the site since the deviation occurred.

Case 45

The scanner failed during the last full-body PET-TT (head-to-toe) scan of the day, about 10 minutes after the PET scan had started. The radiographer informed the patient that the equipment had malfunctioned. The radiographer initially tried to fix the equipment him/herself but then called medical technical support and a medical physicist. By this time, the patient had been moved from the examination table to the waiting area for possible further steps. It quickly became apparent that even if the equipment could be repaired, it would require an intervention that would take about 45 minutes. At that point, the amount of radioactive isotope administered to the patient would be too low for the successful examination. The chief physician of the nuclear medicine unit decided to postpone the examination to a later date, which was communicated to the patient. Images had been obtained from the head down to the lower lungs, but due to the patient's medical history, the isotope physician deemed it insufficient as imaging information was needed from head to toe.

Technical support, in collaboration with the manufacturer, investigated the cause of the malfunction. The device's computed tomography collimation control unit and data transfer unit were broken. The supplier's service department ordered spare parts to fix the issue.

Due to the need for repeating the examination, the patient was subjected to an unintended medical exposure of 23.9 mSv as an effective dose.

 

More deviations will be added to the page later.

3

Case 1

A CT scan was performed on a large patient according to the trauma protocol. However, the trauma imaging protocol did not start as expected due to device's inadequate imaging software which did not take into account the patient's size. The patient had to be imaged in two different stages. The total dose received by the patient from the examinations was approximately 70 mSv, of which the additional dose was estimated to be over 10 mSv. The operator will ensure that the necessary imaging software is installed on the device.

Case 2

The patient's CT scan was interrupted due to a device malfunction. Maintenance visited the site to repair the device, but the image data could not be restored during the maintenance. The patient later came back for a successful CT scan, during which it was noticed that the images from the original scan could also be fully restored. In the future, the radiographers will attempt to restore the images before re-imaging.

 

More deviations will be added to the page later.

Radiation safety deviations in industry and research

1

Case 1

The shield of a radiation source used in the process industry broke off and fell from a height of a few meters. There were no workstations next to the radiation source, and the shutter of the source was locked in closed position. The workers were not exposed to radiation. The supplier of the source has maintained the device and the factory has carried out a root cause analysis of the incident to ensure that nothing similar happens in the future.

Case 2

In the production facilities of an industrial radiography site, a locked tin shed was located next to the filming location. During radiography, noises began to be heard from the shed and the radiographers immediately stopped filming. Two outside workers were present in the shed and were exposed for a total of about two minutes. Both were exposed to an estimated dose of 12.25 µSv.

Case 3

A recycling metal company reported the discovery of a radiating object in a scrap lot. The radiation gate alarmed, even though the scrap batch was driven through the gate several times, so based on this, the entire load was measured with a hand-held meter. The piece was identified as depleted uranium (uranium-238) and was stored in the company's radiation source storage. No workers were exposed to radiation due to the deviation.

Case 4

When using open sources, the worker had inadvertently touched his goggles with contaminated work gloves, and contamination had thus entered the eyebrow area. The contamination was removed by rinsing. The estimated exposure time was approximately 5 to 60 minutes. The dose to a small area of skin was estimated to be 10 mSv.

Case 5

A radiopharmaceutical manufacturing site produced a drug labelled with fluorine-18. Three people participated in the production. The drug was dispensed with a dispenser into product bottles in a lead-shielded dispensing cabinet. After dispensing, the product bottles are dropped into a radiation shield in the take-out hatch on the side of the dispensing cabinet. During the drop, the sound of breaking glass was heard and the fixed dose rate meters in the production laboratory began to alarm. The cover of the radiation shield was in place, causing the falling bottle to break when it hit the cover.

Forgetting the cover was a human error. The workers received a small additional radiation exposure because of the error, calculated at 33 µSv each. As a result of the radiation safety deviation, workers were advised to take extra care whenever handling open sources.

Case 6

A recycled metal company reported a radiating object found among scrap metal, which set off alarms at several radiation gates. The entire load of scrap metal was unloaded, and a cylindrical object was identified as the radiating object by measurements with a radiation meter. The piece was identified by as depleted uranium (uranium-238) and was stored in the company's radiation source storage after the discovery. No workers were exposed to radiation because of the incident.

Case 7

Four radiation sources to be installed were in the same transport container. The installer had to handle the radiation source capsules longer than usual to be able to choose the right source to be installed, because the identification information of the sources was not clearly marked.
For the first radiation source, the attachment was not successful, the source fell back into the transport container and had to be reattached. The second source was installed without any problems, but the third one was again difficult to install. The last source was moved as planned, as the challenging points were known due to previous events. However, the installer was exposed to extra radiation due to poorly planned installation work. The effective dose resulting from the radiation safety deviation was 0.8 mSv and the equivalent dose to the hands was 5.45 mSv.

Case 8

During a cleaning day, a small piece with a radiation source label was found in a company. This source was separate from the actual measuring equipment to which it belonged. Those working on the premises did not know what it was or where it belonged.

The measuring device, which had the radiation source as an ionizer of gases, was stored years ago when an employee retired. In that situation, apparently no knowledge was passed on that such a device even existed. Nor was the measuring device found in the company's device register. The radiation source was transferred for proper disposal. No one is known to have been exposed to radiation.

Case 9

A holder of a radiation source asked STUK how they could properly dispose of the disused sealed source device. The device contained a krypton-85 source with an initial activity of 1850 MBq. STUK (Finnish radiation and nuclear safety authority) told the owner of the device that the device would have required a safety licence and instructed on how to dispose of the source.

In response to STUK's request for further clarification, the holder of the source replied that it had acquired the source in 1999. The device was decommissioned in 2011. The holder of the source was not aware of the obligation to apply for a safety license, as the seller of the equipment had never informed of this. The device was properly disposed of.

Case 10

A radiating source was found in a metal yard with a dose rate of 68.16 uSv/h measured at the surface (the background is 0.11 uSv/h). According to the contact person, it was a piece of a stainless-steel pipe. The piece of pipe had been lifted into a plastic bucket and removed from the rest of the operation. At STUK's request, the operator identified the nuclide as Radium-226 using a meter borrowed from another unit of the company. The tube was delivered to a company that handles radioactive waste.

Case 11

An industrial company was doing maintenance work inside a tank, but the shutter of the radiometric level gauge on the side of the tank was not closed despite the work permit. The sealed source in the level gauge was a cobalt-60 source with a current activity of approximately 310 MBq. Several people worked in the tank over a four-day period. The estimated radiation doses were below the record threshold.

The reason for the deviation was found to be deficiencies in the work permit system for radiation sources. In addition, the markings on the tank, including the closure of the radiation sources, were poorly visible. The operator updated the work permit system for radiation sources and renewed and checked the warning labels on the tanks.

Case 12

A piece was found in the scrap metal load of a company processing recycled metal, which triggered an alarm at the radiation measurement port. The piece was searched for in the load with the help of portable hand-held radiation detectors and taken apart. The piece was detected to contain radioactive radium-226 and it was delivered for disposal as radioactive waste.

Case 13

An employee producing radiopharmaceuticals was finishing dispensing a batch of radiopharmaceuticals and was transferring the dispensing hose to a lead-lined waste container used to age radioactive waste. During the transfer, a needle at the end of one of the hoses came loose from the needle guard and scratched the protective glove on the other hand and caused a small scratch on the base of the index finger. The employee removed the gloves and measured the skin with a contamination meter. The hand was rinsed with warm water. After rinsing, the result did not differ from the background, indicating that all the radiopharmaceutical on the skin had been washed away.

2

Case 1

A deviation occurred at the engineering workshop in connection with industrial radiography imaging, as a result of which the worker was exposed to additional radiation. The worker worked alone and carried out industrial imaging in an enclosed container. The operator inadvertently got too close to the subject, and the container lid was mistakenly left open. The worker was exposed to secondary radiation. In addition, the radiation alarm he used was out of order. According to the instructions, an assistant should have been used in the imaging. The calculated radiation dose to the employee was 9 µSv.

Case 2

Industrial radiography imaging was carried out at the bottom of a large basin. The imaging was performed by three workers. Two workers taking the scan remained with the radiation source and the third worker took the panel to the subject to be imaged and stayed within safe sight of it. The location of imaging was maze-like and cramped, and people moved through the hatches. One passageway was missed due to this, and an outside worker got close to the area being imaged. The imaging was stopped when the outside worker was detected. The calculated radiation exposure was no more than 1 µSv.

More deviations will be added to the page later.

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