PHSOR05 Presentation Time: 9:20 AM

Purpose

To assess practice patterns and physics staffing levels for a range of HDR brachytherapy (BT) procedures across different clinical settings within the US.

Materials and Methods

A survey was designed to assess practice patterns of the US physics brachytherapy workforce. The survey was distributed in October 2023 by IROC-Houston (U24CA180803) using RedCap in the form of an email with background, instructions, and a non-personalized link to the survey. The survey covered: i) demographics, employment, experience level, and equipment, ii) practice patterns, and case load, iii) time and intensity as a function of procedure complexity and challenges/satisfaction associated with HDR BT. We present survey responses from section (ii) and results from a sub-analysis performed to assess physics FTE allocation. Chi-squared tests were used for group comparisons with significance assessed at the p<0.05 level.

Results

Of 429 respondents, 365 respondents performed HDR BT and were included for analysis. The percentage of respondents reporting particular HDR BT practice patterns is noted in () below in 1)- 4) and a sub-analysis for assessing physics full time equivalent (FTE) allocation is in 5). 1) Gynecologic (GYN) treatments using single channel (96%), 2-3 channels (78%), 4-12 channels (44%), and GYN ≥13 channels (33%), in addition to skin (33%), prostate (32%), breast (22%), and sarcoma (10%). 2) MRI-based treatment planning performed frequently (14%), sometimes (19%), or never (67%). 3) Interstitial BT performed frequently (33%), sometimes (23%), or never (44%). 4) The average number of physicist FTE allocated to HDR BT <1.0 (53%), 1.0-1.9 (23%), ≥ 2.0 (10%). 5) The percentage of FTE ≥1.0 assigned to different practice settings is shown below in a)-d) and compared, indicating statistically significant differences (p<0.05) for: a) Planning with MRI vs. without MRI: 52% vs. 32%. b) Interstitial vs. no interstitial: 50% vs. 26%. c) Annual volume grouped by applicator type (<25 patients vs. ≥25 patients): GYN single; 27% vs. 52%. GYN 2-3 channels; 34% vs. 64%. GYN 4-12 channels; 48% vs. 74%. GYN 13+ channels; 55% vs. 88%. Prostate interstitial; 44% vs. 69%. d) Hospital setting (non-academic vs. academic); 31.2% vs. 56%. If MRI based planning or interstitial BT is performed, the likelihood of physics FTE ≥1.0 was higher than their counterpart groups. Regardless of complexity, respondents reported a higher physics FTE when treating a higher volume of patients per year (≥ 25 patients). Also, academic hospitals were associated with ≥1.0 physics FTE. Of note, the current overall MRI utilization rate for HDR BT (33%) did not change compared to the ABS practice patterns survey for MRI- based HDR BT for GYN cancer in 2014.

Conclusion

To our knowledge, this is the first survey of US medical physicists for HDR BT practice patterns and physics staffing. Our survey reflects that patient volume and HDR BT procedure complexity are influential factors for increased physics FTE. Proper physics staffing estimation and recommendations accounting for complexity and patient volume need further assessment by professional societies and leaders.