[Influence of disease prognosis and age on the radiation risk from diagnostic nuclear medicine (bone scintigraphy as an example)]

Of the study was to assess the influence of the patient age and the survival of patients undergoing bone scintigraphy on the calculations of the theoretical lifetime loss.

The evaluated data set included 216 patients undergoing a bone scan for the first time in 1980. From 182 patients a study end point (either the date of death, or existing registration in the German resident office on the 31.12.1995) was obtained. The theoretical life time loss was based on the formalism previously presented by Schicha und Wellner (13).

In 74% of the examined patients a malignant disease was present. 28% of the patients had died within one year of the examination. At the end of the follow-up period, of at least 15 years, 58% of the patients were deceased. The theoretical lifetime loss due to radiation exposure within this specified patient group was estimated to be 0.152 d/mSv. Assuming an age distribution of the general population and statistically derived life expectancy, this value should be 0.437 d/mSv.

The estimates regarding the risk of diagnostic procedures using ionizing radiation should take into account the limited life expectancy of patients in hospitals.