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Introduction: Due to the limited target volume and irregular body surface, irradiating the chest wall (CW) and lymphatic nodes is more challenging. IMRT and VMAT (volumetric modulated arc therapy) are two treatment delivery techniques that help to improve dose coverage and homogeneity while reducing irradiation to the heart and ipsilateral (I/L) lung. The use of a hybrid treatment planning approach for the ca-breast will impact the treatment plan. The hybrid planning system must be reviewed and compared to alternative treatment options for ca-breast cancer. Material and Methods: For 10 patients undergoing left-sided breast chest wall irradiation, the 3 distinct planning techniques (FiF [Field-in-field], IMRT, and Hybrid IMRT) were evaluated. A prescription dose of 40 Gy in 15 fractions was used for the planned target volume (PTV). To compare plans, dose-volume histograms (DVHs) were assessed for PTV and organs at risk. Results: D95% of PTV was 37.10 ± 0.48 Gy in FiF, but considerably raised to 39.32 ± 0.34 Gy and 38.39 ± 0.29 Gy in IMRT (p=0.01) and Hybrid IMRT (p=0.01). When compared to IMRT (0.981 ± 0.014) and Hybrid IMRT (0.970 ± 0.013) FiF plans have the lowest CI value of 0.931 ± 0.026. IMRT plans (0.087 ± 0.021) were found to be more homogeneous than other 2 planning techniques (0.111 ± 0.013 [FiF, p=0.016], 0.107 ± 0.021[hybrid IMRT, p=0.056]). Conclusion: Hybrid IMRT treatment plans for the ca-breast are recommended because they provide superior and similar PTV dose coverage and OAR sparing compared to FiF and IMRT plans. Hybrid IMRT plans feature lower MU and BOT, as well as a smaller low dose volume in comparison to IMRT. [ABSTRACT FROM AUTHOR]

Objectives: This article introduces a new method to design the radiation therapy planning after radical surgery for breast cancer in order to provide a better homogeneity of the dose distribution in the junction region between the supra clavicular fossa and chest wall. Methods: A total of 15 women who received supra clavicular and chest wall irradiation therapy for breast cancer after radical surgery at Cancer Hospital Chinese Academy of Medical Sciences, Shenzhen Center, Shenzhen, China, between 1 October 2018 and 30 November 2019 were included. The prescription dose was 50 Gy/25 fractions. We designed a new plan on the basis of the original plan for each patient on an Varian Eclipse 13.6 planning system, which added two subfields to each tangential opposing field to change the dose distribution at the junction region. Statistical analysis of the target dose distribution – homogeneity index, conformal index, and irradiation doses to the ipsilateral lung, contralateral lung, heart, left‐side breast, and spinal cord – was carried out for the two groups and the differences were compared. Results: When comparing the two plans, the planning target volume minimum dose (P = 0.04) and planning target volume of the junction region, which was defined as the target in the junction region minimum dose (P = 0.04), homogeneity index (P = 0.02), and conformal index (P = 0.01) for the new method plan were better than those for the original plan. However, there was no statistically significant difference in all dosimetric parameters of the organs at risk (P > 0.05) between the new and traditional method plans. Conclusion: Both plans by new and traditional methods for breast cancer after radical surgery can meet the clinical requirements. The prescription dose coverage, conformal index, and homogeneity index for the target in the new method plan were better than those in the traditional method plan. The new method plan provided a better homogeneity of the dose distribution in the junction region, but had no obvious effect on the dose distribution of the organs at risk. As a result, this new planning method can be used in clinical settings. [ABSTRACT FROM AUTHOR]

This study aims to compare the technical feasibility and benefits of four different planning techniques, VMAT, helical tomotherapy, IMRT and Field in Field, for synchronous bilateral breast cancer patients. In this study, two patients with early bilateral breast cancer after breast conservation surgery were planned for radiotherapy. Three different treatment planning techniques were generated for each patient on the Eclipse treatment planning system, and both patients were planned on the Tomotherapy planning system. For planning target volumes (PTVs), the mean doses, values of D2, D98, conformity index and homogeneity index were reported. For the organs at risk, the analysis included the mean dose and VXGy, depending on the organs (lungs, heart). In all techniques used in this study, there was no difference in D98% tPTV, while the lowest D2% was seen in HT plans. HT was the best in conformity and homogeneity index. For Pat#1 and Pat#2, the mean dose (Dmean) to total lungs were 10.8;10.5, 11;13,5, 10.3;10 and 12.2;14.5 Gy for FinF, IMRT, HT and VMAT, respectively and the mean dose to the heart was 5.6, 5.7, 7.9 and 6.8Gy (Pat#1); 4.6, 8, 8.4 and 6.3Gy (Pat#2), respectively. Heart volume at high doses (V25Gy, V30Gy) was approximately 80% lower for HT and 90% lower for VMAT than for FinF. The highest total motor unit value (14555 MUs) was seen in HT plans. Among the SBBC radiotherapy treatment plans, the HT plans improved the PTV dose coverage and dose homogeneity with improved sparing of lungs and heart. [ABSTRACT FROM AUTHOR]

A new planning method for Craniospinal Irradiation by Eclipse treatment planning system using Field alignment, Field-in-Field technique was developed. Advantage of this planning method was also studied retrospectively for previously treated five patients of medulloblastoma with variable spine length. Plan consists of half beam blocked parallel opposed cranium, and a single posterior cervicospine field was created by sharing the same isocenter, which obviates divergence matching. Further, a single symmetrical field was created to treat remaining Lumbosacral spine. Matching between a inferior diverging edge of cervicospine field and superior diverging edge of a Lumbosacral field was done using the field alignment option. 'Field alignment' is specific option in the Eclipse Treatment Planning System, which automatically matches the field edge divergence as per field alignment rule. Multiple segments were applied in both the spine field to manage with hot and cold spots created by varying depth of spinal cord. Plan becomes fully computerized using this field alignment option and multiple segments. Plan evaluation and calculated mean modified Homogeneity Index (1.04 and 0.1) ensured that dose to target volume is homogeneous and critical organ doses were within tolerance. Dose variation at the spinal field junction was verified using ionization chamber array (I'MatriXX) for matched, overlapped and gap junction spine fields; the delivered dose distribution confirmed the ideal clinical match, over exposure and under exposure at the junction, respectively. This method is simple to plan, executable in Record and Verify mode and can be adopted for various length of spinal cord with only two isocenter in shorter treatment time. [ABSTRACT FROM AUTHOR]