Effective radiation dose to patient and to general population from nuclear medicine procedures: Variations in last twenty-year period

It has been evaluated how changes in nuclear medicine (NM) techniques over the last twenty-year period have modified radiation exposure to the patient and population. For this purpose, the authors estimated the variations in the mean effective dose to the patient, and both the collective and the per capita effective dose to the population of the province of Varese (Italy), derived from radioisotope examinations carried out in the four NM centers of this province in the years 1972, 1981, and 1991. Dosimetric calculations were based on ICRP Publication 53 for most of the radiopharmaceuticals used, and tissue weighting factors were based on ICRP Publication 60. The total number of NM exams carried out was 19.744 in 1972, 31.973 in 1981, and 23.623 in 1991. Between 1972 and 1991 there has been a substantial decrease in the effective irradiation to the patient and to the general population (mean effective dose to the patient: from 21.2 to 6 mSv; per capita mean effective dose: from 0.58 to 0.18 mSv), and in the per capita equivalent dose to some target organs, such as the thyroid (9.6(emitted from)1.5 mSv) and liver (0.51(emitted from)0.07 mSv). At the same time, there has been a significant increase in the per capita equivalent dose to the bladder (0.05(emitted from)0.48 mSv), skeleton (0.08(emitted from)0.36 mSv), and testes (0.02(emitted from)0.15 mSv), and a less marked increase to the ovaries (0.03(emitted from)0.06 mSv). The per capita equivalent dose to red marrow (0.13(emitted from)0.1 mSv) and to the large intestine (0.1(emitted from)0.12 mSv) did not change significantly