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Abstract: Purpose: Radiation therapy (RT) is delivered as adjuvant and salvage therapy after radical prostatectomy for prostate cancer. Interest in dose escalation in this setting may necessitate more advanced RT techniques, such as intensity modulation. This study was designed to compare intensity-modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3DCRT) planning. Methods: Twenty patients were identified who received post--radical prostatectomy RT with 4-field, 3DCRT plans to 68.4 Gy. Contours were revised to comply with the European Organization for Research and Treatment of Cancer consensus guidelines. The IMRT plans with 5 versus 9 coplanar fields were compared for 10 patients. Then the 9-field IMRT plans were compared to 3DCRT in all 20 patients. Differences in dose-volume histogram values were evaluated using 2-tailed paired t tests. Cone beam computed tomographic images were analyzed to evaluate rectum doses in the treatment position during the RT course. The IMRT plans to 72.0 Gy were compared to 3DCRT to 68.4 Gy to be able to consider potential use in dose escalation. Results: The 9-field IMRT plans (vs 3DCRT) improved bladder mean dose and volume receiving 65 Gy or more (V65), as well as rectum mean dose (31.6 Gy vs 36.1 Gy; P < .001), volume receiving 75% or more of the prescription dose (24.4% vs 31.0%; P < .001), and V65 (10.5% vs 20.0%; P < .001). Advantages of IMRT were at the cost of small increases in maximum point doses delivered to the bladder and rectum. Cone beam computed tomographic images (n = 132) were analyzed for 8 patients; rectum mean dose and V65 were also improved by IMRT on these scans. IMRT allowed increasing dose to 72.0 Gy with similar bladder and rectum mean doses, V65, and V40 compared to 3DCRT to a total dose of 68.4 Gy. Conclusions: The IMRT improves dosimetric parameters for the rectum and bladder, which may allow dose escalation after radical prostatectomy. Future studies should determine whether these advantages translate into improved clinical outcomes for prostate cancer patients. [Copyright &y& Elsevier]

Abstract: The 2012 Radiation Oncology Workforce survey was conducted to assess the current state of the entire workforce, predict its future needs and concerns, and evaluate quality improvement and safety within the field. This article describes the dosimetrist segment results. The American Society for Radiation Oncology (ASTRO) Workforce Subcommittee, in conjunction with other specialty societies, conducted an online survey targeting all segments of the radiation oncology treatment team. The data from the dosimetrist respondents are presented in this article. Of the 2573 dosimetrists who were surveyed, 890 responded, which resulted in a 35% segment response rate. Most respondents were women (67%), whereas only a third were men (33%). More than half of the medical dosimetrists were older than 45 years (69.2%), whereas the 45 to 54 years age group represented the highest percentage of respondents (37%). Most medical dosimetrists stated that their workload was appropriate (52%), with respondents working a reported average of 41.7 ± 4 hours per week. Overall, 86% of medical dosimetrists indicated that they were satisfied with their career, and 69% were satisfied in their current position. Overall, 61% of respondents felt that there was an oversupply of medical dosimetrists in the field, 14% reported that supply and demand was balanced, and the remaining 25% felt that there was an undersupply. The medical dosimetrists׳ greatest concerns included documentation/paperwork (78%), uninsured patients (80%), and insufficient reimbursement rates (87%). This survey provided an insight into the dosimetrist perspective of the radiation oncology workforce. Though an overwhelming majority has conveyed satisfaction concerning their career, the study allowed a spotlight to be placed on the profession׳s current concerns, such as insufficient reimbursement rates and possible oversupply of dosimetrists within the field. [Copyright &y& Elsevier]

Purpose: The recently activated Radiation Therapy Oncology Group (RTOG) studies of stereotactic body radiation therapy (SBRT) for non-small-cell lung cancer (NSCLC) require tissue density heterogeneity correction, where the high and intermediate dose compliance criteria were established based on superposition algorithm dose calculations. The study was aimed at comparing superposition algorithm dose calculations with Monte Carlo (MC) dose calculations for SBRT for NSCLC and to evaluate whether compliance criteria need to be adjusted for MC dose calculations. Methods and Materials: Fifteen RTOG 0236 study sets were used. The planning tumor volumes (PTV) ranged from 10.7 to 117.1 cm3. SBRT conformal treatment plans were generated using XiO (CMS Inc.) treatment planning software with superposition algorithm to meet the dosimetric high and intermediate compliance criteria recommended by the RTOG 0813 protocol. Plans were recalculated using the MC algorithm of a Monaco (CMS, Inc.) treatment planning system. Tissue density heterogeneity correction was applied in both calculations. Results: Overall, the dosimetric quantities of the MC calculations have larger magnitudes than those of the superposition calculations. On average, R 100% (ratio of prescription isodose volume to PTV), R 50% (ratio of 50% prescription isodose volume to PTV), D 2cm (maximal dose 2 cm from PTV in any direction as a percentage of prescription dose), and V 20 (percentage of lung receiving dose equal to or larger than 20 Gy) increased by 9%, 12%, 7%, and 18%, respectively. In the superposition plans, 3 cases did not meet criteria for R 50% or D 2cm. In the MC-recalculated plans, 8 cases did not meet criteria for R 100%, R 50%, or D 2cm. After reoptimization with MC calculations, 5 cases did not meet the criteria for R 50% or D 2cm. Conclusions: Results indicate that the dosimetric criteria, e.g., the criteria for R 50% recommended by RTOG 0813 protocol, may need to be adjusted when the MC dose calculation algorithm is used. [Copyright &y& Elsevier]