Commissioning of the first hospital-based PET radiopharmaceutical cyclotron in Greece: personnel dose assessment

Abstract

The role of 18F–fluoro–deoxy–glucose in positron emission tomography (PET) imaging is well established in diagnosis and management of cancer patients. Installations of on-site self-shielded mini cyclotrons are increasing. The Dose on Demand Biomarker Generator BG-75 was installed at Metaxa Cancer Hospital, Greece, in May 2021 and is the first hospital-based PET radiopharmaceutical cyclotron in the country. Personnel expected external exposure was established during commissioning; internal exposure is not expected. Personnel dose was estimated with two methods: survey meter measurements in various locations combined with the time spent in each location, and direct measurement using electronic personal dosemeters. Gamma and neutron radiation readings outside the cyclotron vault were at background levels. Inside the cyclotron vault, the highest recorded radiation readings by the target were 18 μSv h−1 for both gammas and neutrons with cyclotron in operational mode; at one meter, the values were 5 μSv h−1 and 4 μSv h−1, respectively. The annual expected whole body dose per cyclotron operator is 0.6 mSv, and the respective extremity dose 16 mSv. The annual expected whole body and extremity dose for the radiochemist is 0.3 mSv and 25 mSv, respectively. The respective annual dose estimates for the medical physicists are < 1 mSv. The expected personnel doses are well below the regulatory limits and local as low as reasonably achievable (ALARA) levels. With experience and a robust ALARA program, personnel exposure could be further reduced.