Explore the vast range of titles available.

Background Bone metastases in the lower spine and pelvis are effectively palliated with radiotherapy (RT), though this can come with side effects such as radiation induced nausea and vomiting (RINV). We hypothesize that high rates of RINV occur in part because of the widespread use of inexpensive simple unplanned palliative radiotherapy (SUPR), over more complex and resource intensive 3D conformal RT, such as volumetric modulated arc therapy (VMAT). Methods This is a randomized, multi-centre phase III trial of SUPR versus VMAT. We will accrue 250 patients to assess the difference in patient-reported RINV. This study is powered to detect a difference in quality of life between patients treated with VMAT vs. SUPR. Discussion This trial will determine if VMAT reduces early toxicity compared to SUPR and may provide justification for this more resource-intensive and costly form of RT. Trial registration Clinicaltrials.gov identifier: NCT03694015 . Date of registration: October 3, 2018.

Purpose This study aimed to determine an appropriate frequency of image‐guided (IG) schedules for left‐sided postmastectomy radiotherapy by comprehensively evaluating dosimetric, radiobiological, imaging dose, and imaging‐related cost outcomes. Methods A retrospective analysis of 20 patients treated with volumetric modulated arc therapy (VMAT) was conducted. Virtual CT images were generated by deforming the pCT to daily cone‐beam computed tomography (CBCT) using deformable image registration. Accumulated dose, tumor control probability (TCP), normal tissue complication probability (NTCP), imaging dose, and imaging‐related cost were compared among six IG schedules: no image‐guided (NIG), weekly image‐guided (WIG), twice‐weekly image‐guided (TIG), thrice‐weekly image‐guided (THRIG), initial 3 days then weekly image‐guided (3D + WIG), and daily image‐guided (DIG). Results Increasing the frequency of IG schedules significantly improved planning target volume (PTV) dose coverage (D95) and TCP (P < 0.001), with DIG achieving optimal target dose delivery. Although no statistically significant differences were observed in dose to organs at risk (OARs) or NTCP, higher‐frequency schedules showed a trend toward reduced variability. However, cumulative imaging dose increased linearly with the frequency of IG schedules (e.g., contralateral breast: 1.26–31.50 mGy; ipsilateral lung: 2.85–71.25 mGy), and imaging‐related cost increased substantially from NIG to DIG, with differences of approximately 1.7‐ to 25‐fold. THRIG demonstrated a favorable balance, with minimal deviations in PTV D95 (1.38%) and TCP (0.83%) relative to DIG, while reducing imaging dose and cost to approximately 60% of DIG. Conclusion While high frequency IG schedules improve target dose coverage, they are associated with increased imaging dose and imaging‐related cost. Within the CBCT‐guided VMAT workflow evaluated in this study, THRIG may provide a balanced trade‐off between treatment precision, safety, and cost.

Patient specific boluses can increase the skin dose distribution better for treating tumors located just beneath the skin with high-energy radiation than a flat bolus. We introduce a low-cost, 3D-printed, patient-specific bolus made of commonly available materials and easily produced using the “structure from motion” and a simple desktop 3D printing technique. Nine pictures were acquired with an iPhone camera around a head phantom. The 3D surface of the phantom was generated using these pictures and the “structure from motion” algorithm, with a scale factor calculated by a sphere fitting algorithm. A bolus for the requested position and shape based on the above generated surface was 3D-printed using ABS material. Two intensity modulated radiation therapy plans were designed to simulate clinical treatment for a tumor located under the skin surface with a flat bolus and a printed bolus, respectively. The planned parameters of dose volume histogram, conformity index (CI) and homogeneity index (HI) were compared. The printed bolus plan gave a dose coverage to the tumor with a CI of 0.817 compared to the CI of 0.697 for the plan with flat bolus. The HIs of the plan with printed bolus and flat bolus were 0.910 and 0.887, respectively.

Intensity-modulated radiation therapy (IMRT) currently plays an important role in radiotherapy, but its treatment plan quality can vary significantly among institutions and planners. Treatment plan quality control (QC) is a necessary component for individual clinics to ensure that patients receive treatments with high therapeutic gain ratios. The voxel-weighting factor-based plan re-optimization mechanism has been proved able to explore a larger Pareto surface (solution domain) and therefore increase the possibility of finding an optimal treatment plan. In this study, we incorporated additional modules into an in-house developed voxel weighting factor-based re-optimization algorithm, which was enhanced as a highly automated and accurate IMRT plan QC tool (TPS-QC tool). After importing an under-assessment plan, the TPS-QC tool was able to generate a QC report within 2 minutes. This QC report contains the plan quality determination as well as information supporting the determination. Finally, the IMRT plan quality can be controlled by approving quality-passed plans and replacing quality-failed plans using the TPS-QC tool. The feasibility and accuracy of the proposed TPS-QC tool were evaluated using 25 clinically approved cervical cancer patient IMRT plans and 5 manually created poor-quality IMRT plans. The results showed high consistency between the QC report quality determinations and the actual plan quality. In the 25 clinically approved cases that the TPS-QC tool identified as passed, a greater difference could be observed for dosimetric endpoints for organs at risk (OAR) than for planning target volume (PTV), implying that better dose sparing could be achieved in OAR than in PTV. In addition, the dose-volume histogram (DVH) curves of the TPS-QC tool re-optimized plans satisfied the dosimetric criteria more frequently than did the under-assessment plans. In addition, the criteria for unsatisfied dosimetric endpoints in the 5 poor-quality plans could typically be satisfied when the TPS-QC tool generated re-optimized plans without sacrificing other dosimetric endpoints. In addition to its feasibility and accuracy, the proposed TPS-QC tool is also user-friendly and easy to operate, both of which are necessary characteristics for clinical use.

Background A new implementation has been made on CloudMC, a cloud-based platform presented in a previous work, in order to provide services for radiotherapy treatment verification by means of Monte Carlo in a fast, easy and economical way. A description of the architecture of the application and the new developments implemented is presented together with the results of the tests carried out to validate its performance. Methods CloudMC has been developed over Microsoft Azure cloud. It is based on a map/reduce implementation for Monte Carlo calculations distribution over a dynamic cluster of virtual machines in order to reduce calculation time. CloudMC has been updated with new methods to read and process the information related to radiotherapy treatment verification: CT image set, treatment plan, structures and dose distribution files in DICOM format. Some tests have been designed in order to determine, for the different tasks, the most suitable type of virtual machines from those available in Azure. Finally, the performance of Monte Carlo verification in CloudMC is studied through three real cases that involve different treatment techniques, linac models and Monte Carlo codes. Results Considering computational and economic factors, D1_v2 and G1 virtual machines were selected as the default type for the Worker Roles and the Reducer Role respectively. Calculation times up to 33 min and costs of 16 € were achieved for the verification cases presented when a statistical uncertainty below 2% (2σ) was required. The costs were reduced to 3–6 € when uncertainty requirements are relaxed to 4%. Conclusions Advantages like high computational power, scalability, easy access and pay-per-usage model, make Monte Carlo cloud-based solutions, like the one presented in this work, an important step forward to solve the long-lived problem of truly introducing the Monte Carlo algorithms in the daily routine of the radiotherapy planning process.

Introduction Attendance of staff and use of resources during treatment have an impact on costs. For palliative radiotherapy, no reliable data are available on the subject. Therefore, the measurement of selected variables (staff absorbance and room occupancy) based on daily palliative irradiation was the aim of our prospective study. The analysis is part of a larger study conducted by the German Society of Radiation Oncology (DEGRO). Patients, material, and methods A total of 172 palliative radiation treatments were followed up prospectively between October 2009 and March 2010. The study was performed at two experienced radiotherapy departments (Herne and Bielefeld) and evaluated the attendance of medical personnel and room occupancy related to the selected steps of the treatment procedure: treatment planning and daily application of radiation dose. Results Computed tomography for treatment planning engaged the unit for 19 min (range: 17–22 min). The localization of target volume required on average 28 min of a technician’s working time. The mean attendance of the entire staff (radiation oncologist, physicist, technician) for treatment planning was 159 min, while the total room occupancy was 140 min. Depending on the type of treatment, the overall duration of a radiotherapy session varied on average between 8 and 18 min. The staff was absorbed by the first treatment session (including portal imaging) for 8–27 min. Mean room occupancy was 18 min (range: 6–65 min). The longest medical staff attendance was observed during an initial irradiation session (mean: 11 min). Radiotherapy sessions with weekly performed field verifications occupied the rooms slightly longer (mean: 10 min, range: 4–25 min) than daily radiotherapy sessions (mean: 9 min, range: 3–29 min). We observed that the patients’ symptoms, their condition, and their social environment confounded the time schedule. Conclusions Target localization, treatment planning, and performance of palliative radiotherapy absorb resources to an extent comparable to nonpalliative treatment. Because of unexpected events, the time schedule before and during radiotherapy may reveal strong interindividual variability.

In January 2002, the departments of radiotherapy at the University Hospital of North Norway and the Norwegian Radium Hospital were connected through a 2 Mbit/s digital telecommunication line. The treatment planning systems at the two institutions were connected and videoconferencing units were installed. We explored the feasibility of remote treatment planning, supervision, second opinions and education. Tests involved two dummy cases and six patients. Remote simulation procedures were carried out for five patients. A cost-minimization analysis was performed. Treatment planning was not completely successful as the software could not handle plans including bolus or weighting between the fields. Remote supervision was possible. A common patient record and radiotherapy system, including digital imaging, digital prescription and approval forms and digital signature, were felt to be desirable. The threshold (break-even point) comparing the costs of telemedicine with those of transportation by air was 12 patients/year. Telemedicine in radiotherapy appears to be feasible, but some limitations must be overcome.

Purpose The purpose of the study was to investigate if surface guided radiotherapy (SGRT) can decrease setup deviations for tangential and locoregional breast cancer patients compared to conventional laser‐based setup (LBS). Materials and Methods Both tangential (63 patients) and locoregional (76 patients) breast cancer patients were enrolled in this study. For LBS, the patients were positioned by aligning skin markers to the room lasers. For the surface based setup (SBS), an optical surface scanning system was used for daily setup using both single and three camera systems. To compare the two setup methods, the patient position was evaluated using verification imaging (field images or orthogonal images). Results For both tangential and locoregional treatments, SBS decreased the setup deviation significantly compared to LBS (P < 0.01). For patients receiving tangential treatment, 95% of the treatment sessions were within the clinical tolerance of ≤ 4 mm in any direction (lateral, longitudinal or vertical) using SBS, compared to 84% for LBS. Corresponding values for patients receiving locoregional treatment were 70% and 54% for SBS and LBS, respectively. No significant difference was observed comparing the setup result using a single camera system or a three camera system. Conclusions Conventional laser‐based setup can with advantage be replaced by surface based setup. Daily SGRT improves patient setup without additional imaging dose to breast cancer patients regardless if a single or three camera system was used.

The Varian Ethos system allows for online adaptive treatments through the utilization of artificial intelligence (AI) and deformable image registration which automates large parts of the anatomical contouring and plan optimization process. In this study, treatments of intact prostate and prostate bed, with and without nodes, were simulated for 182 online adaptive fractions, and then a further 184 clinical fractions were delivered on the Ethos system. Frequency and magnitude of contour edits were recorded, as well as a range of plan quality metrics. From the fractions analyzed, 11% of AI generated contours, known as influencer contours, required no change, and 81% required minor edits in any given fraction. The frequency of target and noninfluencer organs at risk (OAR) contour editing varied substantially between different targets and noninfluencer OARs, although across all targets 72% of cases required no edits. The adaptive plan was the preference in 95% of fractions. The adaptive plan met more goals than the scheduled plan in 78% of fractions, while in 15% of fractions the number of goals met was the same. The online adaptive recontouring and replanning process was carried out in 19 min on average. Significant improvements in dosimetry are possible with the Ethos online adaptive system in prostate radiotherapy.

Purpose The purpose of this study was to demonstrate the potential utility of cone‐beam computed tomography (CBCT)‐guided online adaptive radiotherapy (ART) under end‐exhalation breath‐hold (EE‐BH) conditions for pancreatic cancer (PC). Methods Eleven PC patients who underwent 15‐fraction volumetric‐modulated arc therapy under EE‐BH conditions were included. Planning CT images and daily 165 CBCT images were imported into a dedicated treatment planning system. The prescription dose was set to 48 Gy in 15 fractions. The reference plan was automatically generated along with predefined clinical goals. After segmentation was completed on CBCT images, two different plans were generated: One was an adapted (ADP) plan in which re‐optimization was performed on the anatomy of the day, and the other was a scheduled (SCH) plan, which was the same as the reference plan. The dose distributions calculated using the synthetic CT created from both planning CT and CBCT were compared between the two plans. Independent calculation‐based quality assurance was also performed for the ADP plans, with a gamma passing rate of 3%/3 mm. Results All clinical goals were successfully achieved during the reference plan generation. Of the 165 sessions, gross tumor volume D98% and clinical target volume D98% were higher in 100 (60.1%) and 122 (74.0%) ADP fractions. In each fraction, the V3 Gy < 1 cm3 of the stomach and duodenum was violated in 47 (28.5%) and 48 (29.1%), respectively, of the SCH fractions, whereas no violations were observed in the ADP fractions. There were statistically significant differences in the dose–volume indices between the SCH and ADP fractions (p < 0.05). The gamma passing rates were above 95% in all ADP fractions. Conclusions The CBCT‐guided online ART under EE‐BH conditions successfully reduced the dose to the stomach and duodenum while maintaining target coverage.