Is eye lens dosimetry needed in nuclear medicine?

INTRODUCTION: The exact level of exposure experienced by nuclear medicine personnel, whose work often requires performing manual procedures involving radioactive isotopes, is associated with the form of radiation source used. The variety of radionuclides and medical procedures, and the yearly increase in the number of patients, as well as the change of the individual dose limit for the lens of the eye from a value of 150 mSv yr-1 to 20 mSv yr-1 , mean that issues of eye lens routine dosimetry become interesting from the radiation protection point of view.

OBJECTIVE: This paper presents an analysis of the exposure of the eye lenses of nuclear medicine department personnel, as well as those of personnel in the facilities that produce radiopharmaceuticals for the purpose of diagnosis by positron emission tomography, from the viewpoint of the advisability of routine eye lens exposure monitoring, taking into account changes in the dose limit for the lens of the eye.

MATERIALS AND METHODS: The paper considers the two most commonly used radionuclides for diagnostic purposes 99m Tc, 18 F, and-for therapeutic purposes-131 I. Dose measurements were made using thermoluminescent detectors.

RESULTS: The estimated exposure analysis identifies the cases when the maximum annual value of the personal dose equivalent, in terms of Hp(3), exceeds threefold the new limit value (20 mSv yr-1 ).

CONCLUSIONS: It is recommended that Hp(3) doses be routinely monitored in the group of radiopharmacists who label pharmaceuticals with the radionuclide 99m Tc and in chemists working in 18 F-FDG quality control departments in production units, where this is carried out manually.