Background: The use of adjuvant radiotherapy (RT) shows a significantly decreased incidence of local recurrence (LR) in soft tissue sarcomas (STS). This study aimed to assess the treatment scheme’s effect in patients with primary STS treated at one institution. Methods: In this phase 2 trial, 311 patients aged ≥18 years with primary, locally advanced STS of the extremity or trunk wall were assigned to multimodal therapy conducted at one institution. The preoperative RT scheme consisted of 5 Gy per fraction for a total dose of 25 Gy. Surgery was performed within 2–4 days from the last day of RT. The primary endpoint was LR-free survival (LRFS). Adverse events of the treatment were assessed. Results: We included 311 patients with primary locally advanced STS. The median tumor size was 11 cm. In total, 258 patients (83%) had high-grade tumors. In 260 patients (83.6%), clear surgical margins (R0) were obtained. Ninety-six patients (30.8%) had at least one type of treatment adverse event. LR was observed in 13.8% patients. The 5-year overall survival was 63%. Conclusion: In this group, with a significant percentage of patients with extensive, high-grade STS, hypofractionated preoperative RT was associated with good local control and tolerance.

Dosimetric characteristics of 3D-printed plates using different infill percentage and materials was the purpose of our study. Test plates with 5%, 10%, 15% and 20% honeycomb structure infill were fabricated using TPU and PLA polymers. The Hounsfield unit distribution was determined using a Python script. Percentage Depth Dose (PDD) distribution in the build-up region was measured with the Markus plane-parallel ionization chamber for an open 10x10 cm² field of 6 MV. PDD was measured at a depth of 1 mm, 5 mm, 10 mm and 15 mm. Measurements were compared with Eclipse treatment planning system calculations using AAA and Acuros XB algorithms. The mean HU for CT scans of 3D-printed TPU plates increased with percentage infill increase from -739 HU for 5% to -399 HU for 20%. Differences between the average HU for TPU and PLA did not exceed 2% for all percentage infills. Even using a plate with the lowest infill PDD at 1 mm depth increase from 44.7% (without a plate) to 76.9% for TPU and 76.6% for PLA. Infill percentage did not affect the dose at depths greater than 5 mm. Differences between measurements and TPS calculations were less than 4.1% for both materials, regardless of the infill percentage and depth. The use of 3D-printed light boluses increases the dose in the build-up region, which was shown based on the dosimetric measurements and TPS calculations.

Background. Irradiation of a larger volume of the target may lead to an increase of the doses delivered to the surrounding organs at risk (OAR) for post-prostatectomy patients with a higher risk of nodal involvement. It was anticipated that IMRT significantly improved OAR sparing. The aim of this study was to provide a dosimetric comparison between conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) treatment plans for patients with prostate cancer irradiated to the prostate bed and pelvic lymph-nodal area. Materials and methods. The 3D-CRT and IMRT plans were created for ten patients after prostatectomy. The treatment plans were generated for the prostate bed (PTV1) and the pelvic lymph nodes (PTV2). The sum of PTV1 and PTV2 was irradiated to a mean dose of 46 Gy in 23 fractions, and additionally PTV1 was irradiated to a mean dose of 18 Gy in 9 fractions. Target coverage and the doses delivered to the pelvic bones, the rectum, the bladder, the bowel bag, and the femurs, were compared between techniques. The Wilcoxon signed-rank test was used to compare the dosimetric parameters. Results. The dosimetric quality of 3D-CRT and IMRT plans were comparable for target coverage (the mean value of PTV1 V95%, the mean value of PTV2 V95% all > 99%). The IMRT plans resulted in significant reductions in the pelvic bones V30[%], V40[%], the rectum V40[%], V50[%], V60[%], the bladder V40[%], V50[%], V60[%], the bowel bag V45[cc] and the femurs V40[%]. Conclusions. The analysis presented in this paper demonstrates that the IMRT technique reduces the delivered dose to the OARs. Most interesting was the possibility of reducing the delivered dose to the pelvic bones and the bowel bag. This allowed us to expect a decreased risk of acute hematologic toxicity and acute gastrointestinal toxicity. Background. Irradiation of a larger volume of the target may lead to an increase of the doses delivered to the surrounding organs at risk (OAR) for post-prostatectomy patients with a higher risk of nodal involvement. It was anticipated that IMRT significantly improved OAR sparing. The aim of this study was to provide a dosimetric comparison between conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) treatment plans for patients with prostate cancer irradiated to the prostate bed and pelvic lymph-nodal area. Materials and methods. The 3D-CRT and IMRT plans were created for ten patients after prostatectomy. The treatment plans were generated for the prostate bed (PTV1) and the pelvic lymph nodes (PTV2). The sum of PTV1 and PTV2 was irradiated to a mean dose of 46 Gy in 23 fractions, and additionally PTV1 was irradiated to a mean dose of 18 Gy in 9 fractions. Target coverage and the doses delivered to the pelvic bones, the rectum, the bladder, the bowel bag, and the femurs, were compared between techniques. The Wilcoxon signed-rank test was used to compare the dosimetric parameters. Results. The dosimetric quality of 3D-CRT and IMRT plans were comparable for target coverage (the mean value of PTV1 V95%, the mean value of PTV2 V95% all > 99%). The IMRT plans resulted in significant reductions in the pelvic bones V30[%], V40[%], the rectum V40[%], V50[%], V60[%], the bladder V40[%], V50[%], V60[%], the bowel bag V45[cc] and the femurs V40[%]. Conclusions. The analysis presented in this paper demonstrates that the IMRT technique reduces the delivered dose to the OARs. Most interesting was the possibility of reducing the delivered dose to the pelvic bones and the bowel bag. This allowed us to expect a decreased risk of acute hematologic toxicity and acute gastrointestinal toxicity.

The aim of the study was to verify the accuracy of calculations of dose distributions for electron beams performed using the electron Monte Carlo (eMC) v.10.0.28 algorithm implemented in the Eclipse treatment planning system (Varian Medical Systems). Implementation of the objective of the study was carried out in two stages. In the first stage the influence of several parameters defined by the user on the calculation accuracy was assessed. After selecting a set of parameters for which the best results were obtained a series of tests were carried. The tests were carried out in accordance with the recommendations of the Polish Society of Medical Physics (PSMP). The calculation and measurement of dose rate under reference conditions for semi quadratic and shaped fields were compared by individual cut-outs. We compared the calculated and measured percent depth doses, profiles and output factors for beams with an energy of 6, 9, 12, 15 and 18 MeV, for semi quadratic fields and for three different SSDs 100, 110, and 120 cm. All tests were carried out for beams generated in the Varian 2300CD Clinac linear accelerator. The results obtained during the first stage of the study demonstrated that the highest compliance between the calculations and measurements were obtained for the mean statistical uncertainty equal to 1, and the parameter responsible for smoothing the statistical noise defined as medium. Comparisons were made showing similar compliance calculations and measurements for the calculation grid of 0.1 cm and 0.25 cm and therefore the remaining part of the study was carried out for these two grids. In stage 2 it was demonstrated that the use of calculation grid of 0.1 cm allows for greater compliance of calculations and measurements. For energy 12, 15 and 18 MeV discrepancies between calculations and measurements, in most cases, did not exceed the PSMP action levels. The biggest differences between measurements and calculations were obtained for 6 MeV energy, for smallest fields and large SSD distances. Despite these discrepancies between calculations the model was adopted for clinical use.