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Purpose: Many patients with metastatic cancer live years beyond diagnosis, and there remains a need to improve the therapeutic ratio of metastasis-directed radiation for these patients. This study aimed to assess a process for delivering cost-effective palliative proton therapy to the spine using diagnostic scan-based planning (DSBP) and prefabricated treatment delivery devices. Materials and Methods: We designed and characterized a reusable proton aperture system that adjusts to multiple lengths for spine treatment. Next, we retrospectively identified 10 patients scan treated with thoracic proton therapy who also had a diagnostic computed tomography within 4 months of simulation. We contoured a T6-T9 target volume on both the diagnostic scans (DS) and simulation scans (SS). Using the aperture system, we generated proton plans on the DS using a posterior-anterior beam with no custom range compensator to treat T6-T9 to 8 Gy × 1. Plans were transferred to the SS to compare coverage and normal tissue doses, followed by robustness analysis. Finally, we compared normal tissue doses and costs between proton and photon plans. Results were compared using the Wilcoxon signed-rank test. Results: Median D95% on the DS plans was 101% (range, 100%-102%) of the prescription dose. Median Dmax was 107% (range, 105%-108%). When transferred to SS, coverage and hot spots remained acceptable for all cases. Heart and esophagus doses did not vary between the DS and SS proton plans (P >.2). Robustness analysis with 5 mm X/Y/Z shifts showed acceptable coverage (D95% > 98%) for all cases. Compared with the proton plans, the mean heart dose was higher for both anterior-posterior/posterior-anterior and volumetric modulated arc therapy plans (P < .01). Cost for proton DSBP was comparable to more commonly used photon regimens. Conclusion: Proton DSBP is technically feasible and robust, with superior sparing of the heart compared with photons. Eliminating simulation and custom devices increases the value of this approach in carefully selected patients.
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PURPOSE: Research productivity metrics are important for decisions regarding hiring, retention, and promotion in academic medicine, and these metrics can vary widely among different disciplines. This article examines productivity metrics for radiation therapy physicists (RTP) in the United States. METHODS AND MATERIALS: Database searches were performed for RTP faculty at US institutions that have RTP residencies accredited by the Commission on Accreditation of Medical Physics Education Programs (CAMPEP). Demographics, academic rank, number of publications, academic career length, Hirsch index (h-index), m-quotient, and history of National Institutes of Health (NIH) funding as a principal investigator (PI) were collected for each RTP. Logistic regression was performed to determine the probability of academic rank as a function of h-index and m-quotient. Statistical tests used included the Wilcoxon ranked sum test and the Pearson χ2 test. RESULTS: A total of 1038 faculty and staff were identified at 78 institutions with CAMPEP-accredited residencies. The average RTP academic career duration is 13.5 years, with 46.7 total publications, h-index of 10.7, and m-quotient of 0.66. Additionally, 10.5% of RTP have a history of NIH funding as a PI. Large disparities were found in academic productivity of doctoral-prepared physicists compared to those with a terminal master's degree. For differences in junior and senior faculty, statistical tests yielded significance in career duration, number of publications, h-index, and m-quotient. Gender disparities were identified in the overall distribution of RTP consistent with the membership of the American Association of Physicists in Medicine. Further gender disparities were found in the number of doctoral-prepared RTP and physicists in senior faculty roles. CONCLUSIONS: This manuscript provides objective benchmark data regarding research productivity of academic RTP. These data may be of interest to faculty preparing for promotion, and also to institutional leadership.
