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Breast, chest wall, and regional nodal irradiation have been associated with an improved outcome in high-risk breast cancer patients. Complex treatment planning is often utilized to ensure complete coverage of the target volume while minimizing the dose to surrounding normal tissues. The 2 techniques evaluated in this report are the partially wide tangent fields (PWTFs) and the 4-field photon/electron combination (the modified "Kuske Technique"). These 2 techniques were evaluated in 10 consecutive breast cancer patients. All patients had computerized tomographic (CT) scans for 3D planning supine on a breast board. The breast was defined clinically by the physician and confirmed radiographically with radiopaque bebes. The resulting dose-volume histograms (DVHs) of normal and target tissues were then compared. The deep tangent field with blocks resulted in optimal coverage of the target and the upper internal mammary chain (IMC) while sparing of critical and nontarget tissues. The wide tangent technique required less treatment planning and delivery time. We compared the 2 techniques and their resultant DVHs and feasibility in a busy clinic.

To determine the dose received by the contralateral breast during primary breast irradiation using IMRT compared to conventional tangential field techniques.Between March 2003 and March 2004, 83 patients with breast carcinoma were treated using 6, 10, or mixed 6/18 MV photons (65 with tangential IMRT technique and 18 with 3-dimensional technique using tangential fields with wedges) for primary breast irradiation following breast-conserving surgery. Paired thermoluminescent dosimeters (TLDs) were placed on each patient's contralateral breast, 4 and 8 cm from the center of the medial border of the tangential field. The TLDs were left on the patient during a single fraction and then measured 24 h afterwards.The mean dose delivered with photons to the primary breast for all patients was 4999 cGy (SD = 52) with a mean single fraction dose of 199 cGy (SD = 8). The mean percent of the prescribed dose to the contralateral breast measured at the 4- and 8-cm positions were 7.19% (SD = 2.28) and 4.63% (SD = 2.12), respectively, for patients treated with IMRT compared to 11.22% (SD = 2.73) and 10.70% (SD = 3.44), respectively, for the patients treated with conventional tangential field techniques. This represented a 36% and 57% reduction at the 4 and 8-cm contralateral positions, respectively, in the mean dose to the contralateral breast using IMRT compared to 3-D technique which was statistically significant (p0.0005,0.0005, respectively).Primary breast irradiation with tangential IMRT technique significantly reduces the dose to the contralateral breast compared to conventional tangential field techniques.

PURPOSE This study was designed to compare the dose received by the contralateral breast during primary breast irradiation using intensity-modulated radiotherapy with the dose received via conventional tangential field techniques. METHODS/MATERIALS Between March 2003 and March 2004, 44 patients with breast carcinoma were treated using 6-, 10-, or mixed 6/18-MV photons (36 with tangential intensity-modulated radiotherapy technique and eight with three-dimensional technique using tangential fields with wedges) for primary breast irradiation after breast-conserving surgery. Paired thermoluminescent dosimeters were placed on each patient's contralateral breast, 4 cm from the center of the medial border of the tangential field. The thermoluminescent dosimeters were left on the patient during a single fraction and then measured 24 hours later. RESULTS The mean dose delivered with photons to the primary breast for all patients was 4998 cGy [SD = 52], and the mean single fraction dose was 200 cGy [SD = 9]. The mean percent of the prescribed dose to the contralateral breast was 7.74% (SD = 2.35) for patients treated with intensity-modulated radiotherapy, compared with 9.74% [SD = 2.04] for the patients treated with conventional tangential field techniques. This represented a 20% reduction in the mean dose to the contralateral breast with the use of intensity-modulated radiotherapy when compared with the dose received via the three-dimensional technique, a result that was statistically significant. CONCLUSION Primary breast irradiation with tangential intensity-modulated radiotherapy technique significantly reduces the dose to the contralateral breast when compared with conventional tangential techniques.

Objectives The goals of this study were to evaluate the feasibility of pelvic intensity-modulated radiotherapy (IMRT) in the adjuvant treatment of gynecologic malignancies and to compare the dose–volume histograms (DVHs) and determine the potential impact on acute and long-term toxicity based on the dose to target and nontarget tissues for both planning techniques. Methods Ten consecutive patients referred for adjuvant radiotherapy for gynecologic malignancies at the University of Pittsburgh School of Medicine and Magee–Womens Hospital were selected for CT-based treatment planning using the ADAC 3D version 4.2g and the NOMOS Corvus IMRT version 4.0. Normal tissues and critical structures were contoured on axial CT slices by both systems in conjunction with a gynecologic radiologist. These regions included internal, external, and common iliac nodal groups, rectum, upper 4 cm of vagina, bladder, and small bowel. Conventional treatment planning included 3D four-field box using 18-MV photons designed to treat a volume from the L 5 /S 1 border superiorly to the bottom of the ischial tuberosity on the AP/PA field and shaped blocks on the lateral fields to minimize the dose to the rectum and small bowel. A seven-field technique using 6-MV photons was used for IMRT. Restraints on small bowel for IMRT were set at 23.0 Gy ± 5% and 35.0 Gy± 5% for the rectum and 37.5 Gy ± 5% for the bladder while simultaneously delivering full dose (45.0 Gy) to the intrapelvic nodal groups in 1.8-Gy daily fractions. The dose–volume histograms where then compared for both treatment delivery systems. Results The volume of each organ of interest (small bowel, bladder, and rectum) receiving doses in excess of 30 Gy was compared in the 3D and IMRT treatment plans. The mean volume of small bowel receiving doses in excess of 30 Gy was reduced by 52% with IMRT compared with 3D. A similar advantage was noted for the rectum (66% reduction) and the bladder (36% reduction). The nodal regions at risk and the upper vagina all received the prescribed dose of 45.0 Gy. Conclusions Intensity-modulated radiotherapy appears to offer several advantages over conventional 3D radiotherapy (3D CRT) planning for adjuvant radiotherapy for gynecologic malignancies. These include a significant reduction in treatment volume for bladder, rectum, and small bowel. It is anticipated that this reduction in volume of normal tissue irradiated would translate into overall reduction in acute and potentially late treatment-related toxicity. Prospective trials are necessary to better evaluate the advantages in a larger group of patients.

Radical radiotherapy of pelvic malignancies (e.g., vulva, anus) includes therapeutic dosage to the inguinal nodes. To minimize the dosage to the femoral head, the transmission block technique has been developed to fully irradiate the central pelvis midplane and inguinal nodes. Originally, this technique compensated for dose inhomogeniety in the transverse plane only. In some patients, however, we have observed a significant dose variation along the sagittal plane. The authors have developed a lead compensation technique to homogenize the sagittal dose variations due to the longitudinal sloping in the patient, along with further refinements in this technique. Dosimetric and technical details are also discussed.