Calibration of gamma camera for use in internal monitoring program for workers occupationally exposed by ¹³¹I in a nuclear medicine service

¹³¹I is one of the most used radionuclides in the practice of nuclear medicine, it is used for both diagnostic and therapy proposes, a practice that represents a risk of incorporation by this radionuclide. The International Atomic Energy Agency (IAEA) recommends the implementation of an internal monitoring program on workers potentially exposed to annual effective doses higher than 1 mSv, as for example, those who handle ¹³¹I for therapy. The Brazilian Nuclear Energy Commission (CNEN) establishes that workers potentially exposed to annual doses greater than 1 mSv due to the incorporation of ¹³¹I must be submitted to a routine internal monitoring program. In Brazil there are available only five laboratories qualified to provide internal monitoring services. This scenario turns impossible to attend all possible demand of internal monitoring if such regulation were applied by CNEN, besides that it would generate a high cost for the Nuclear Medicine Services (NMS). This work used a simple and low cost methodology for calibration of a gamma camera to be used in an in vivo routine internal monitoring program of ¹³¹I. The calibration techniques carried out in this work proved to be easy and quick to be performed, in addition to providing the possibility of carrying out a routine internal monitoring program in the SMN itself, which allows complying the internal monitoring requirement of ¹³¹I required by CNEN without significant additional costs. (author)