Medical examinations
X-ray examinations and procedures
X-ray imaging of patients is the most common way of using radiation in healthcare. A total of approximately 5.7 million X-ray examinations and procedures are performed annually. The most common X-ray examination is an intraoral X-ray examination of a single tooth or a few adjacent teeth; approximately 1.8 million of such examinations are performed annually. The total number of dental X-ray examinations per year is 2.2 million.
In addition to dental examinations, conventional X-ray examinations are common. The most common conventional X-ray examination is a thorax radiograph, with approximately 0.5 million being performed annually. Mammographic screening examinations and various X-ray examinations of the limbs are also common. Overall, a total of approximately 2.6 million X-ray examinations are performed each year.
The number of both dental and native X-ray examinations has decreased somewhat in recent years. In contrast, the number of CT scans, angiographies and radiological procedures has increased markedly. In recent years, however, the number of native and dental X-ray examinations has decreased faster than the number of other X-ray examinations has increased.
The most common CT scan is a head scan with approximately 180,000 scans performed every year. Other common CT-scans are scans of the body, abdomen and thorax. In total, approximately 650,000 CT examinations are performed annually. By contrast, approximately 46,000 angiographies and approximately 65,000 radiological procedures involving exposure to radiation are performed every year.
Nuclear medicine examinations
Approximately 43,000 nuclear medicine examinations are performed on patients annually. The most common nuclear medicine examinations are tumour imaging, examinations of skeletal and soft tissues and examinations of the cardiovascular system. Relatively few nuclear medicine examinations are performed on children, approximately a thousand examinations per year. The number of nuclear medicine examinations performed annually has remained pretty much the same in recent years. Over the past decade or so, the number of gamma scans and single photon emission computed tomography (SPECT) scans has declined sharply, while the number of SPET-CT and PET-CT scans has increased.
The most commonly used radionuclides in nuclear medicine examinations are Tc-99m, F-18 and I-123. The decrease in the number of conventional nuclear medicine examinations is also reflected as a decrease in the use of Tc-99m-labelled radiopharmaceuticals. On the other hand, the strong increase in PET scans is reflected as an increased use of F-18.
Radiotherapy
Approximately 40,000 Finnish patients are diagnosed with cancer each year, of which approximately half receive radiotherapy as part of their treatment. The number of cancer patients is expected to grow at an annual rate of a few per cent per year.
Approximately 3,000 patients are treated with radionuclide therapy per year.
Radiation exposure in Finland in health care
For several years already, the largest sources of artificial radiation exposure have been X-ray examinations and procedures as well as nuclear medicine examinations. Exposure to the general public can be estimated by combining the radiation doses of all the different examinations multiplied by the number of each examination performed.
The radiation dose at the population level, i.e. the collective dose, can be compared between years or countries. In this case, the collective dose is typically reported per individual, as if the radiation exposure caused by the examinations were distributed evenly among the population.
X-ray examinations and procedures
X-ray examinations and procedures cause a calculated effective dose of approximately 0.7 mSv for each Finn. On the whole, the average effective dose of a Finn is slightly less than 6 mSv.
Although the number of dental and conventional X-ray examinations performed is large, they account for only a small part of the collective dose – less than one per cent of the collective dose comes from dental examinations and about 10 per cent comes from conventional X-ray examinations. In contrast, approximately 70 % of the collective effective dose from X-ray examinations and procedures comes from CT scans. Since CT-scans are becoming more common, their share of the collective dose is also increasing.
Radiological and cardiological procedures represent a small part of the total number of examinations, but the resulting radiation exposure is higher. Therefore, any significant changes in the number of examinations are interesting. Overall, the collective effective dose from X-ray examinations and procedures has increased significantly over the past ten years, but it is still quite low in international comparisons.
Nuclear medicine examinations
Nuclear medicine examinations cause a calculated effective dose of approximately 0.04 mSv for each Finn. More than half of this is due to the use of radioisotopes and the rest is caused by CT scans performed during a nuclear medicine examination. The collective effective dose caused by nuclear medicine examinations has increased slightly in recent years. There has been an increase in CT scans, but the collective effective dose from radiopharmaceuticals has remained the same.
Radiotherapy and radionuclide therapy
Exposure caused by radiotherapies and radionuclide therapies is not taken into account when determining the population exposure caused by radiation used in health care. Only a small fraction of the population receives radiotherapy, namely patients who have been diagnosed with a disease that requires radiotherapy. One such disease is cancer. It has therefore been internationally agreed that the exposure caused by these therapies is not included in the calculated dose of the entire population.