Finger doses due to Ga-68-labelled pharmaceuticals in PET departments-results of a multi-centre pilot study

Introduction: Although the use of Ga-68 has increased substantially in nuclear medicine over the last decade, there is limited information available on occupational exposure due to Ga-68. The purpose of this study is to determine the occupational extremity exposure during the preparation, dispensing and administration of Ga-68-labelled radiopharmaceuticals. Method: Workers in eight centres wore a ring dosimeter for all tasks involving Ga-68-labelled radiopharmaceuticals for a minimum of one month. Additionally, the fingertip dose was monitored in two centres and the hand with the highest ring dose during Ga-68 procedures was also identified in one centre. Results: The median normalised ring dose for Ga-68 procedures was found to be 0.25 mSv GBq(-1) (range 0.01-3.34). The normalised Ga-68 ring doses recorded in this study are similar to that found in the literature for F-18. This study is consistent with previous findings that the highest extremity dose is found on the non-dominant hand. A limited sub study in two of the centres showed a median fingertip to base of the finger dose ratio of 4.3. Based on this median ratio, the extrapolated annual Ga-68 fingertip dose for 94% of the workers monitored in this study would be below Category B dose limit (150 mSv) and no worker would exceed Category A dose limit (500 mSv). Conclusion: When appropriate shielding and radiation protection practices are employed, the extremity dose due to Ga-68 is comparable to that of F-18 and is expected to be well below the regulatory limits for the majority of workers.