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Historically, total body irradiation (TBI) has been delivered using static, parallel opposed photon beams (2D-TBI). Recently, centers have increasingly used intensity-modulated radiation therapy (IMRT) techniques for TBI. Relative to 2D-TBI, IMRT can reduce doses to critical organs (i.e., lungs and kidneys) while delivering myeloablative doses to the rest of the body, so it may decrease the risk of toxicity while maintaining oncologic outcomes. Despite these potential benefits, delivering TBI using IMRT introduces new challenges in treatment planning and delivery. We describe the extensive experience with IMRT-based TBI at Stanford University and City of Hope Cancer Center. These groups, and others, have reported favorable clinical outcomes and have developed methods to optimize treatment planning and delivery. A critical next step is to evaluate the broader adoption of this approach. Therefore, IMRT-based TBI will be incorporated into a prospective, multi-institutional Children's Oncology Group study with careful procedures and safeguards in place., (© 2024 Wiley Periodicals LLC.)

Purpose: Create a comprehensive automated solution for pediatric and adult VMAT-CSI including contouring, planning, and plan check to reduce planning time and improve plan quality., Methods: Seventy-seven previously treated CSI patients (age, 2-67 years) were used for creation of an auto-contouring model to segment 25 organs at risk (OARs). The auto-contoured OARs were evaluated using the Dice Similarity Coefficient (DSC), 95% Hausdorff Distance (HD95), and a qualitative ranking by one physician and one physicist (scale: 1-acceptable, 2-minor edits, 3-major edits). The auto-planning script was developed using the Varian Eclipse Scripting API and tested with 20 patients previously treated with either low-dose VMAT-CSI (12 Gy) or high-dose VMAT-CSI (36 Gy + 18 Gy boost). Clinically relevant metrics, planning time, and blinded physician review were used to evaluate significance of differences between the auto and manual plans. Finally, the plan preparation for treatment and plan check processes were automated to improve efficiency and safety of VMAT-CSI., Results: The auto-contours achieved an average DSC of 0.71 ± 0.15, HD95 of 4.81 ± 4.68, and reviewers' ranking of 1.22 ± 0.39, indicating close to "acceptable-as-is" contours. Compared to the manual CSI plans, the auto-plans for both dose regimens achieved statistically significant reductions in body V50% and D mean for parotids, submandibular, and thyroid glands. The variance in the dosimetric parameters decreased for the auto-plans as compared to the manual plans indicating better plan consistency. From the blinded review, the auto-plans were marked as equivalent or superior to the manual-plans 88.3% of the time. The required time for the auto-contouring and planning was consistently between 1-2 hours compared to an estimated 5-6 hours for manual contouring and planning., Conclusions: Reductions in contouring and planning time without sacrificing plan quality were obtained using the developed auto-planning process. The auto-planning scripts and documentation will be made freely available to other institutions and clinics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Simiele, Romero, Wang, Chen, Lozko, Severyn, Skinner, Yang, Xing, Gibbs, Hiniker and Kovalchuk.)

Purpose: To report adverse effects of high dose total body irradiation (TBI) delivered using a volumetric arc therapy (VMAT) technique and to assess pulmonary toxicity at dose rates of 40 and 100 monitor units per minute (MU/min)., Methods and Materials: This retrospective study included patients >18 years old who received ≥8 Gy TBI using a VMAT technique. The TBI dose was prescribed to a planning target volume consisting of a 0.5 cm retraction of the body with the lungs subtracted. The objective function specified planning target volume coverage goals of D100% ≥ 90% and Dmax <130%. A lung dose control structure consisting of a 1 cm retraction of the lung volume was limited to Dmean <75%. Treatments were initially delivered with a dose rate of 40 MU/min for the thoracic isocenters and 100 MU/min for the other isocenters. Beginning in January 2021, a dose rate of 100 MU/min was used for all isocenters. All treatments were administered in 2 Gy fractions delivered twice daily. Acute toxicity was assessed for 30 days after TBI., Results: A total of 29 patients were included in this analysis who received TBI between January 2019 and October 2021. Prescription dose ranged from 8 to 12 Gy. Mean lung dose was 7.9 Gy (SD, 1.4 Gy) for patients treated at 40 MU/min and for patients treated at 100 MU/min 7.1 Gy (SD, 1.3 Gy). Mucositis was the most common grade 3 toxicity and occurred in 10 (34%) patients. Only 1 instance of pneumonitis was observed and occurred in a patient who received a mean lung dose of 10.1 Gy delivered at 40 MU/min., Conclusions: In this cohort of patients who received high dose TBI using a VMAT technique, the composite rate of acute toxicity was not unexpectedly high. We did not observe an increase in lung toxicity after increasing the dose rate of the thoracic isocenters from 40 MU/min to 100 MU/min., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Purpose/objectives: To evaluate dosimetric differences between auto-planned volumetric modulated arc therapy (VMAT) total body irradiation (TBI) technique and two-dimensional radiotherapy using anterior-posterial/posterio-anterial beams (2D AP/PA) TBI technique., Methods: Ten pediatric patients treated with VMAT-TBI on Varian c-arm linac were included in this study. VMAT-TBI plans were generated using our in-house developed and publicly shared auto-planning scripts. For each VMAT-TBI plan, a 2D AP/PA plan was created replicating the institution's clinical setup with the patient positioned at extended source to skin distance (SSD) with a compensator to account for differences in patient thickness, 50% transmission daily lung blocks, and electron chest wall boosts prescribed to 50% of the photon prescription. Clinically relevant metrics were analyzed and compared between the VMAT and 2D plans., Results: All VMAT-TBI plans achieved planned target volume (PTV) D90% ≥ 100% of prescription. VMAT-TBI PTV D90% significantly increased (7.1% ± 2.9%, p < .001) compared to the 2D technique, whereas no differences were observed in global D max (p < .2) and PTV V110% (p < .4). Compared to the 2D plans, significant decreases in the D mean to the lungs (-25.6% ± 11.5%, p < .001) and lungs-1 cm (-34.1% ± 10.1%, p < .001) were observed with the VMAT plans. The VMAT technique also enabled decrease of dose to other organs: kidneys D mean (-32.5% ± 5.0%, p < .001) and lenses D max (-5.3% ± 8.1%, p = .03); and in addition, for 2 Gy prescription: testes/ovaries D mean (-41.5% ± 11.5%, p < .001), brain D mean (-22.6% ± 5.4%, p = .002), and thyroid D mean (-18.2% ± 16.0%, p = .03)., Conclusions: Superior lung sparing with improved target coverage and similar global D max were observed with the VMAT plans as compared to 2D plans. In addition, VMAT-TBI plans provided greater dose reductions in gonads, kidneys, brain, thyroid, and lenses., (© 2023 Wiley Periodicals LLC.)

Purpose: The aim of this study was to present the first-year experience of treating patients using intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) with a biology-guided radiation therapy machine, the RefleXion X1 system, installed in a clinical setting., Methods and Materials: A total of 78 patients were treated on the X1 system using IMRT and SBRT from May 2021 to May 2022. Clinical and technical data including treatment sites, number of pretreatment kilovoltage computed tomography (kVCT) scans, beam-on time, patient setup time, and imaging time were collected and analyzed. Machine quality assurance (QA) results, machine performance, and user satisfactory survey were also collected and reported., Results: The most commonly treated site was the head and neck (63%), followed by the pelvis (23%), abdomen (8%), and thorax (6%). Except for 5 patients (6%) who received SBRT treatments for bony metastases in the pelvis, all treatments were conventionally fractionated IMRT. The number of kVCT scans per fraction was 1.2 ± 0.5 (mean ± standard deviation). The beam-on time was 9.2 ± 3.5 minutes. The patient setup time and imaging time per kVCT was 4.8 ± 2.6 minutes and 4.6 ± 1.5 minutes, respectively. The daily machine output deviation was 0.4 ± 1.2% from the baseline. The patient QA had a passing rate of 97.4 ± 2.8% at 3%/2 mm gamma criteria. The machine uptime was 92% of the total treatment time. The daily QA and kVCT image quality received the highest level of satisfaction. The treatment workflow for therapists received the lowest level of satisfaction., Conclusions: One year after the installation, 78 patients were successfully treated with the X1 system using IMRT and/or SBRT. With the recent Food and Drug Administration clearance of biology-guided radiation therapy, our department is preparing to treat patients using positron emission tomography-guidance via a new product release, which will address deficiencies in the current image-guided radiation therapy workflow., Competing Interests: Nataliya Kovalchuk reports a relationship with RefleXion Medical that includes funding grants., (© 2023 The Authors.)

Purpose: The aim of this study was to apply the Six Sigma methodology and failure mode and effect analysis (FMEA) to mitigate errors in intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) treatment planning with the first clinical installation of RefleXion X1., Methods and Materials: The Six Sigma approach consisted of 5 phases: define, measure, analyze, improve, and control . The define, measure, and analyze phases consisted of process mapping and an FMEA of IMRT and SBRT treatment planning on the X1. The multidisciplinary team outlined the workflow process and identified and ranked the failure modes associated with the plan check items using the American Association of Physicists in Medicine Task Group 100 recommendations. Items with the highest average risk priority numbers (RPNs) and severity ≥ 7 were prioritized for automation using the Eclipse Scripting Application Programming Interface (ESAPI). The "improve" phase consisted of developing ESAPI scripts before the clinical launch of X1 to improve efficiency and safety. In the "control" phase, the FMEA ranking was re-evaluated 1 year after clinical launch., Results: Overall, 100 plan check items were identified in which the RPN values ranged from 10.2 to 429.0. Fifty of these items (50%) were suitable for automation within ESAPI. Of the 10 highest-risk items, 8 were suitable for automation. Based on the results of the FMEA, 2 scripts were developed: Planning Assistant, used by the planner during preparation for planning, and Automated Plan Check, used by the planner and the plan checker during plan preparation for treatment. After 12 months of clinical use of the X1 and developed scripts, only 3 errors were reported. The average prescript RPN was 138.0, compared with the average postscript RPN of 47.8 ( P < .05), signifying a safer process., Conclusions: Implementing new technology in the clinic can be an error-prone process in which the likelihood of errors increases with increasing pressure to implement the technology quickly. To limit errors in clinical implementation of the novel RefleXion X1 system, the Six Sigma method was used to identify failure modes, establish quality control checks, and re-evaluate these checks 1 year after clinical implementation., (© 2023 The Author(s).)

Purpose: In cervical cancer brachytherapy, adding interstitial needles to intracavitary applicators can enhance dosimetry by improving target coverage while limiting normal tissue dose. However, its use is limited to a subset of practitioners with appropriate technical skill. We designed tandem anchored radially guiding interstitial templates (TARGITs) with a 3-dimensional (3D) printing workflow to optimize needle placement and facilitate greater ease-of-use of intracavitary/interstitial (IC/IS) technique. This study compared dosimetry and procedure characteristics between tandem and ovoid (T&O) implants using TARGIT technique versus non-TARGIT technique., Methods and Materials: This single-institution retrospective cohort study included patients undergoing T&O brachytherapy as part of definitive radiation treatment for cervical cancer between February 2017 and January 2021. TARGIT technique was implemented from November 2019 onwards; all prior procedures involved non-TARGIT technique using a no needle or freehand needle approach. Target coverage, dose to organs at risk, and procedure times were evaluated and compared between TARGIT technique and non-TARGIT technique., Results: The cohort included 70 patients with cervical cancer who underwent 302 T&O procedures: 68 (23%) with TARGIT technique and 234 (77%) with non-TARGIT technique, which included 133 no needle and 101 freehand needle implants. TARGIT implants involved longer average procedure times (+6.3 minutes, P < .0001). TARGIT implants achieved a higher mean high-risk clinical target volume V100% than non-TARGIT implants (+4.4%, P = .001), including for large tumors 30 cm 3 or greater (+8.1%, P = .002). Average D90 was 4.6 Gy higher and average D98 was 3.2 Gy higher for TARGIT technique compared with non-TARGIT technique (P = .006 and P = .02). Total treatment doses to rectum, bowel, and bladder were not significantly different for TARGIT versus non-TARGIT technique., Conclusions: The 3D-printed TARGIT approach to T&O brachytherapy achieved greater tumor coverage while sparing normal tissues, particularly for large tumor volumes, with only a slight increase in average procedure time. TARGIT represents a creative technological solution for increasing accessibility of advanced IC/IS brachytherapy technique for cervical cancer definitive radiation treatment., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: The RefleXion X1 is a novel radiotherapy machine designed for image-guided radiotherapy (IGRT) and biology-guided radiotherapy (BgRT). Its treatment planning system (TPS) generates IMRT and SBRT plans for a 6MV-FFF beam delivered axially via 50 firing positions with the couch advancing every 2.1 mm. The purpose of this work is to report the TPS commissioning results for the first clinical installation of RefleXion™ X1., Methods: CT images of multiple phantoms were imported into the RefleXion TPS to evaluate the accuracy of data transfer, anatomical modeling, plan evaluation, and dose calculation. Comparisons were made between the X1, Eclipse™, and MIM™. Dosimetric parameters for open static fields were evaluated in water and heterogeneous slab phantoms. Representative clinical IMRT and SBRT cases were planned and verified with ion chamber, film, and ArcCHECK @ measurements. The agreement between TPS and measurements for various clinical plans was evaluated using Gamma analysis with a criterion of 3%/2 mm for ArcCHECK @ and film. End-to-end (E2E) testing was performed using anthropomorphic head and lung phantoms., Results: The average difference between the TPS-reported and known HU values was -1.4 ± 6.0 HU. For static fields, the agreements between the TPS-calculated and measured PDD 10 , crossline profiles, and inline profiles (FWHM) were within 1.5%, 1.3%, and 0.5 mm, respectively. Measured output factors agreed with the TPS within 1.3%. Measured and calculated dose for static fields in heterogeneous phantoms agreed within 2.5%. The ArcCHECK @ mean absolute Gamma passing rate was 96.4% ± 3.4% for TG 119 and TG 244 plans and 97.8% ± 3.6% for the 21 clinical plans. E2E film analysis showed 0.8 mm total targeting error for isocentric and 1.1 mm for off-axis treatments., Conclusions: The TPS commissioning results of the RefleXion X1 TPS were within the tolerances specified by AAPM TG 53, MPPG 5.a, TG 119, and TG 148. A subset of the commissioning tests has been identified as baseline data for an ongoing QA program., (© 2022 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)

Introduction: Total body irradiation (TBI) is an important component of many conditioning regimens for hematopoietic stem cell transplantation (HSCT), most commonly used in pediatric and adolescent/young adult (AYA) patients. We aimed to evaluate outcomes and toxicities among pediatric and AYA patients treated with TBI utilizing volumetric modulated arc therapy total body irradiation (VMAT-TBI)., Methods: We reviewed pediatric and AYA patients treated with VMAT-TBI at our institution from 2019 to 2021. Data on patient and disease characteristics, treatment details, outcomes and toxicities were collected. Overall survival (OS) and relapse-free survival (RFS) were analyzed using the Kaplan-Meier method., Results: Among 38 patients, 16 (42.1%) were treated with myeloablative regimens and 22 (57.9%) with nonmyeloablative regimens. Median age was 7.2 years (range: 1-27) and median follow-up was 8.7 months (range: 1-21). Lungs D mean was 7.3 ± 0.3 Gy for myeloablative regimens (range: 6.8-7.8). Kidneys were spared to average mean dose of 71.4 ± 4.8% of prescription dose. Gonadal sparing was achieved for patients treated for nonmalignant diseases to D mean of 0.7 ± 0.1 Gy. No patient experienced primary graft failure; one (2.6%) experienced secondary graft failure. The most common grade 1-2 acute toxicities were nausea (68.4%) and fatigue (55.3%). Mucositis was the most common grade 3-4 acute toxicity, affecting 39.5% of patients. There were no cases of pneumonitis or nephrotoxicity attributable to TBI., Conclusion: VMAT-TBI offers increased ability to spare organs at risk in pediatric and AYA patients undergoing HSCT, with a favorable acute/subacute toxicity profile and excellent disease control., (© 2022 Wiley Periodicals LLC.)

This study reports the beam commissioning results for the first clinical RefleXion Linac., Methods: The X1 produces a 6 MV photon beam and the maximum clinical field size is 40 × 2 cm 2 at source-to-axis distance of 85 cm. Treatment fields are collimated by a binary multileaf collimator (MLC) system with 64 leaves with width of 0.625 cm and y-jaw pairs to provide either a 1 or 2 cm opening. The mechanical alignment of the radiation source, the y-jaw, and MLC were checked with film and ion chambers. The beam parameters were characterized using a diode detector in a compact water tank. In-air lateral profiles and in-water percentage depth dose (PDD) were measured for beam modeling of the treatment planning system (TPS). The lateral profiles, PDDs, and output factors were acquired for field sizes from 1.25 × 1 to 40 × 2 cm 2 field to verify the beam modeling. The rotational output variation and synchronicity were tested to check the gantry angle, couch motion, and gantry rotation., Results: The source misalignments were 0.049 mm in y-direction, 0.66% out-of-focus in x-direction. The divergence of the beam axis was 0.36 mm with a y-jaw twist of 0.03°. Clinical off-axis treatment fields shared a common center in y-direction were within 0.03 mm. The MLC misalignment and twist were 0.57 mm and 0.15°. For all measured fields ranging from the size from 1.25 × 1 to 40 × 2 cm 2 , the mean difference between measured and TPS modeled PDD at 10 cm depth was -0.3%. The mean transverse profile difference in the field core was -0.3% ± 1.1%. The full-width half maximum (FWHM) modeling was within 0.5 mm. The measured output factors agreed with TPS within 0.8%., Conclusions: This study summarizes our specific experience commissioning the first novel RefleXion linac, which may assist future users of this technology when implementing it into their own clinics., (© 2022 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)

Purpose: In this article, we describe the technical aspects of the Stanford volumetric modulated arc therapy (VMAT) total body irradiation (TBI) technique, compare it with other VMAT-TBI techniques, and share our initial experience., Methods and Materials: From September 2019 to August 2021, 35 patients were treated with VMAT-TBI at our institution. Treatment planning was performed using in-house developed automated planning scripts. Organ sparing depended on the regimen: myeloablative (lungs, kidneys, and lenses) and nonmyeloablative with benign disease (lungs, kidneys, lenses, gonads, brain, and thyroid). Quality assurance was performed using electronic portal imaging device portal dosimetry and Mobius3D. Robustness was evaluated for the first 10 patients by performing local and global isocenter shifts of 5 mm. Treatment was delivered using image-guided radiation therapy for every isocenter and every fraction. In vivo measurements were performed on the match line between the VMAT and anterior-posterior/posterior-anterior fields and on the testes for the first fraction., Results: The lungs, lungs - 1 cm, and kidneys D mean were consistently spared to 57.6% ± 4.4%, 40.7% ± 5.5%, and 70.0% ± 9.9% of the prescription dose, respectively. Gonadal sparing (D mean  = 0.69 ± 0.13 Gy) was performed for all patients with benign disease. The average planning target volume (PTV) maximum dose to 1 cubic centimeter (D 1cc ) was 120.7% ± 6.4% for all patients. The average Gamma passing rate for the VMAT plans was 98.1% ± 1.6% (criterion of 3%/2 mm). Minimal differences were observed between Mobius3D- and Eclipse AAA-calculated PTV D mean (0.0% ± 0.3%) and lungs D mean (-2.5% ± 1.2%). Robustness evaluation showed that the PTV D max and lungs D mean were insensitive to small positioning deviations between the VMAT isocenters (1.1% ± 2.4% and 1.2% ± 1.0%, respectively). The average match-line dose measurement indicated patient setup was reproducible (96.1% ± 4.5% relative to prescription dose). Treatment time, including patient setup and beam-on, was 47.5 ± 9.5 min., Conclusions: The Stanford VMAT-TBI technique, from simulation to treatment delivery, was presented and compared with other VMAT-TBI techniques. Together with publicly shared autoplanning scripts, our technique may provide the gateway for wider adaptation of this technology and the possibility of multi-institutional studies in the cooperative group setting., (Copyright © 2022 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

Purpose: The first clinical biology-guided radiation therapy (BgRT) system-RefleXion TM X1-was installed and commissioned for clinical use at our institution. This study aimed at evaluating the treatment plan quality and delivery efficiency for IMRT/SBRT cases without PET guidance. Methods: A total of 42 patient plans across 6 cancer sites (conventionally fractionated lung, head, and neck, anus, prostate, brain, and lung SBRT) planned with the Eclipse TM treatment planning system (TPS) and treated with either a TrueBeam ® or Trilogy ® were selected for this retrospective study. For each Eclipse VMAT plan, 2 corresponding plans were generated on the X1 TPS with 10 mm jaws (X1-10mm) and 20 mm jaws (X1-20mm) using our institutional planning constraints. All clinically relevant metrics in this study, including PTV D95%, PTV D2%, Conformity Index (CI), R50, organs-at-risk (OAR) constraints, and beam-on time were analyzed and compared between 126 VMAT and RefleXion plans using paired t -tests. Results: All but 3 planning metrics were either equivalent or superior for the X1-10mm plans as compared to the Eclipse VMAT plans across all planning sites investigated. The Eclipse VMAT and X1-10mm plans generally achieved superior plan quality and sharper dose fall-off superior/inferior to targets as compared to the X1-20mm plans, however, the X1-20mm plans were still considered acceptable for treatment. On average, the required beam-on time increased by a factor of 1.6 across all sites for X1-10mm compared to X1-20mm plans. Conclusions: Clinically acceptable IMRT/SBRT treatment plans were generated with the X1 TPS for both the 10 mm and 20 mm jaw settings.

Conflicts of interest exist when an arrangement potentially exerts inappropriate influence on decision making or professional judgment, or is perceived to do so, and can thus damage the public trust and undermine the integrity of those decisions. Concerns regarding financial conflicts of interest in the medical arena have reached their height as of late, given that physicians now function in a milieu of complex and delicate relationships with pharmaceutical, biotechnology, and medical device industries. Even when such relationships do not correlate with actual compromise of judgment or patient care, it threatens the credibility of both the health care professional and the institution because of the social perception of the effect of these relationships. Although most institutions in the Western world set forth a code of ethics and conflict-of-interest policies to be followed under threat of termination, the Veterans Health Administration (VHA) presents itself as a unique environment in which conflicts of interest are subject to governmental laws, violation of which may not only result in employment-related discipline, but may be sanctioned by civil and criminal penalties. Moreover, these provisions are developed by a national authoritative organization rather than being institution-specific guidelines. Given that many academic physicians working within the VHA may also have a component of their practice in a University setting, it becomes important to understand the differences in policy between these contexts so as not to threaten the public trust in the veracity of decisions made and, therefore, maintain the integrity of the relationship between physician and patient. This article will review aspects of conflict-of-interest policies in the realm of research, financial relationships, foreign travel, and vendor contracting that are particular to the VHA and make it a unique environment to function in as a physician and scientist., (Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)