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Abstract Background Prone breast positioning reduces skin reaction and heart and lung dose, but may also reduce radiation dose to axillary lymph nodes (ALNs). Methods Women with early stage breast cancer treated with whole breast irradiation (WBI) in the prone position were identified. Patients treated in the supine position were matched for treating physician, laterality, and fractionation. Ipsilateral breast, tumor bed, and Level I, II, and III ALNs were contoured according to the RTOG breast atlas. Clips marking surgically removed sentinel lymph nodes (SLN)s were contoured. Treatment plans developed for each patient were retrospectively analyzed. V90% and V95% was calculated for each axillary level. When present, dose to axillary surgical clips was calculated. Results Treatment plans for 46 women (23 prone and 23 supine) were reviewed. The mean V90% and V95% of ALN Level I was significantly lower for patients treated in the prone position (21% and 14%, respectively) than in the supine position (50% and 37%, respectively) (p p % of SLN clips was 47% for patients treated in the supine position and 0% for patients treated in the prone position (p % to SLN clips was 96% for women treated in the supine position but only 13% for women treated in the prone position. Conclusions Standard tangential breast irradiation in the prone position results in substantially reduced dose to the Level I axilla as compared with treatment in the supine position. For women in whom axillary coverage is indicated such as those with positive sentinel lymph node biopsy who do not undergo completion axillary dissection, treatment in the prone position may be inappropriate.

Purpose: The purpose of this study was to provide guidance on quality management for electronic brachytherapy. Materials and Methods: The task group used the risk‐assessment approach of Task Group 100 of the American Association of Physicists in Medicine. Because the quality management program for a device is intimately tied to the procedure in which it is used, the task group first designed quality interventions for intracavitary brachytherapy for both commercial electronic brachytherapy units in the setting of accelerated partial‐breast irradiation. To demonstrate the methodology to extend an existing risk analysis for a different application, the task group modified the analysis for the case of post‐hysterectomy, vaginal cuff irradiation for one of the devices. Results: The analysis illustrated how the TG‐100 methodology can lead to interventions to reduce risks and improve quality for each unit and procedure addressed. Conclusion: This report provides a model to guide facilities establishing a quality management program for electronic brachytherapy. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: In this study, computer modeling was used to compare the relative doses with the bladder, rectum, and bowel when two different brachytherapy modalities were used to treat cervical cancer with a tandem and ovoid applicator. A standard high–dose rate (HDR) 192Ir treatment plan was compared with a “mixed-source” brachytherapy (MSB) treatment plan in which a 50kV electronic brachytherapy X-ray source was substituted for 192Ir as the tandem source. Methods and Materials: A total of 15 three-dimensional CT data sets from cervical cancer patients previously treated with tandem and ovoid applicator were evaluated for the study. Bladder, rectum, bowel, and target volumes were contoured and separate treatment plans were created for MSB and HDR 192Ir applications. Dose–volume histograms were analyzed for each organ at risk. Results: The mean %V 25 for the bladder was 43% vs. 70% for MSB and HDR 192Ir methods, respectively. Similarly, for the rectum mean %V 25 was 34% vs. 48% for MSB and HDR 192Ir. For the bowel, the mean %V 25 was 28% vs. 43% for the MSB and HDR 192Ir methods, respectively. In 16 of 45 organs at risk, %D 2cc values were higher for MSB than HDR 192Ir. Conclusions: MSB is capable of providing target coverage to the cervix, uterus, and paracervical regions equivalent to that provided by HDR 192Ir, while significantly reducing the overall dose to the bladder, rectum, and bowel. This reduction is associated with small regions of increased dose in a significant proportion of patients. [Copyright &y& Elsevier]

Abstract: Purpose: Advantages for electronic brachytherapy (EBT) of the vaginal cuff include decreased physical dose to the bladder and rectum. Here we compare 192Ir with EBT using biological effective dose (BED) to account for the different radiobiological effectiveness (RBE) predicted for low-energy x-rays. Methods and Materials: Fifteen data sets from five consecutive postoperative endometrial cancer patients treated with EBT were analyzed. Treatment planning was performed using PLATO software. The dose was prescribed as 21Gy in three fractions to a depth of 0.5cm. Physical dose, BED3, and BED10 were evaluated for the mucosa, bladder, and rectum. An RBE value of 1.5 was used for BED calculations. Results: Mucosal physical dose is 28.4% greater with EBT (36.6 vs. 28.5Gy, p <0.05). However, the BED10 is increased by 79.1% (55.6 vs. 99.6Gy, p <0.05) and the BED3 by 71.5% (118.8 vs. 203.7Gy, p <0.05). The physical dose (dose to 50% volume of the organ) to the bladder (9.3 vs. 6.6Gy, p <0.05) and rectum (7.2 vs. 4.2Gy, p <0.05) are reduced with EBT. BED3 to the rectum and bladder are also reduced but to a lesser extent (13 vs. 8.3Gy, p <0.05; 18.9 vs. 14.7Gy, p =0.06, respectively). Conclusions: BED takes into account the higher RBE of low-energy photons generated with EBT and provides a more accurate estimate of the biological effect. When using EBT, physical dose may underestimate the biological effect on the vaginal mucosa and overestimate the benefit for the bladder and rectum. Dose adjustment for EBT based on BED should be considered. [Copyright &y& Elsevier]