Survey of radiopharmaceutical dosing strategies for bone and PET scans

Objectives Increased concerns about radiation dose in the public and medical community have motivated efforts to develop diagnostic reference levels in nuclear medicine and an improved understanding of dosing strategies used in current practice. In this work, the Intersocietal Accreditation Commission (IAC) and the SNMMI Dose Optimization task force partnered to summarize dosing strategies across multiple institutions for Tc-99m MDP bone and FDG-PET scans.

Methods Accreditation materials from IAC Nuclear/PET accredited facilities for bone and FDG-whole body PET studies were evaluated. The average administered activity for each facility was calculated from patient reports. Sites were categorized based on their type (hospital, private, mobile, etc.) and their reported dosing strategy (fixed, range or weight-based dosing).

Results Analysis was performed for 225 and 95 facilities performing bone scans and FDG-PET scans, respectively. For bone imaging, 58% of the clinics reported using a range of doses compared to 42% that report using a fixed dose. The average MDP activity was 930 +/- 118 MBq[710 to 1,315 range] MBq (25.1 +/- 3.2 mCi). For FDG-PET, most sites (64%) use a range-based dosing strategy and the overall average activity was 508 +/- 117 [108-875] MBq (13.7 +/- 3.2 mCi). In general, there were no observable major differences in dosing between the types of facilities, except in the case of the mobile centers, which used on average 30% more dose for both bone and PET scanning. However, the numbers of mobile units were small: 1 and 3 for bone and FDG-PET scans, respectively.

Conclusions This survey of a variety of facilities presents anticipated results: on average dosing is in keeping with SNMMI practice guidelines and there is a wide range of dosing strategies in the United States. These types of evaluations are crucial for establishing diagnostic reference levels and communicating the importance of selecting appropriate dosing strategies.