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Purpose: India is rapidly adopting advanced treatments like Stereotactic Radiosurgery (SRS). However, there is a paucity of data on SRS practice. The aim of study is to assess the current status of technology and practices of machine quality assurance (QA) and patient specific quality assurance for SRS in India., Materials and Methods: A survey questionnaire was designed using Google Forms and sent to chief/senior medical physicists across 220 radiotherapy centers in India on July 15, 2022. It contained questions on infrastructure availability, treatment planning, and QA., Results: SRS was found to be extensively used for the treatment of brain metastases (99.3%), followed by meningioma (50.3%), acoustic neuroma (45.5%), and pituitary tumours (33.1%). The most commonly used photon energy and treatment technique were 6MV FFF and VMAT, respectively. A prescription isodose line ranging from 70% to 100% was selected by linac users. Most linac institutes verify pretreatment doses. There was a lack of uniformity in the analysis metrics such as Low Dose Threshold, Dose Difference, and Distance to Agreement. A survey revealed that the variety of SRS QA programs being followed at Indian radiotherapy centers., Conclusion: This is the first study to report the physics practice of SRS in India. The survey shows a need to carry out a postal dose audit for small static photon fields in India., (Copyright © 2024 Copyright: © 2024 Journal of Cancer Research and Therapeutics.)

The radioluminescence (RL) emitted by LiMgPO4 detector under proton beam irradiation was investigated in real time at the radiotherapy facility in the Institute of Nuclear Physics Polish Academy of Sciences in Krakow. The facility uses protons accelerated by the AIC-144 isochronous cyclotron up to the energy of 60 MeV. The measurements of RL were carried out using a remote optical fiber device with a luminophore detector and photomultiplier located at opposite ends of the optical fiber. A thin slice of LiMgPO4 doped with Tm (1.2 mol%) crystal was exposed to the proton beam. The tested detector allowed for the measurement of proton beam current, flux fluence and determination of proton beam time structure parameters. The investigation of LiMgPO4 crystal showed its high sensitivity, fast reaction time to irradiation and possibility of application as the detector for control of proton beam parameters., (© The Author(s) 2023. Published by Oxford University Press.)

Introduction: Despite the development of DOSIRIS™, an eye lens dosimeter, the characteristics of DOSIRIS™ in the area of radiotherapy have not been investigated. The purpose of this study was to evaluate the basic characteristics of the 3-mm dose equivalent measuring instrument DOSIRIS™ in radiotherapy., Methods: Dose linearity and energy dependence were evaluated for the irradiation system based on the calibration method of the monitor dosimeter. The angle dependence was measured by irradiating from a total of 18 directions. Interdevice variation was repeated three times by simultaneously irradiating five dosimeters. The measurement accuracy was based on the absorbed dose measured by the monitor dosimeter of the radiotherapy equipment. Absorbed doses were converted to 3-mm dose equivalents and compared with DOSIRIS™ measurements., Results: Dose linearity was evaluated using the determination coefficient (R 2 ) R 2  = 0.9998 and 0.9996 at 6 and 10 MV, respectively. For energy dependence, although the therapeutic photons evaluated in this study had higher energies than in the previous studies and had a continuous spectrum, the response was equivalent to 0.2-1.25 MeV, well below the IEC 62387 limits. The maximum error at all angles was 15% (angle of 140°) and the coefficient of variation at all angles was 4.70%, which satisfies the standard of the thermoluminescent dosimeter measuring instrument. Accuracy of measurement was determined in terms of the measurement errors for DOSIRIS™ (3.2% and 4.3% at 6 and 10 MV, respectively,) using the 3-mm dose equivalent obtained from the theoretical value as a reference. The DOSIRIS™ measurements met the IEC standard which defines the measurement error of ±30% of the irradiance value in IEC 62387., Conclusions: We found that the characteristics of the 3-mm dose equivalent dosimeter in a high-energy radiation satisfy the IEC standards and have the same measurement accuracy as diagnostic areas such as Interventional Radiology., (© 2023 The Authors. Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.)

Background/aim: We investigated treatment outcomes and complications during reirradiation of patients with oral cancers., Patients and Methods: Six patients who received definitive radiotherapy for oral cancer as the initial treatment and brachytherapy for recurrence were included. Local control and overall survival rates, soft tissue and mandibular complications, and tooth extraction were investigated., Results: The five-year local control and overall survival rates were 83.3% and 100%, respectively. The occurrence rate of grade 2 soft tissue and mandible complications was 33.3%, and the primary sites were the buccal mucosa and the floor of mouth. The positions of the extracted tooth in the two cases were adjacent to the tumor, and one case developed grade 2 complication of the mandible., Conclusion: During recurrence of the buccal mucosa and the floor of mouth cancers, reirradiation should be avoided considering mandibular complications. To avoid reirradiation-related complications, tooth extraction near the radiation field should be avoided., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Topometry is an integral part of irradiation whose task is to repeat the position of the patient set by the simulator to repeat the PTV and the spatial relationship between the radiation field and the risk organs that were identified during planning. The dose distribution formulated in the plan is only an ideal model. There is some gap between the actual and planned dose distribution, especially in overweight patients., Objective: evaluate the effect of anthropometric data on the deviation between the planned dose and the results of dosimetry in vivo in patients with uterine cancer during postoperative irradiation., Materials and Methods: The authors analyzed the results of treatment of 110 patients with stage IB-II uterine can- cer who were treated at the Department of Radiation Therapy of the Institute of Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine from 2016 to 2019. The technique of classical fractionation was used with a single focal dose of 2.0 Gy 5 times a week, the total focal dose was 42.0-50.0 Gy. To assess the effect of the patient's anthropometric data on the difference between the actual and calculated dose, the authors per- formed in vivo dosimetry after the first session and in the middle of the postoperative course of external beam radi- ation therapy., Results: Рatients with BSA < 1.92 m2, had the median relative deviation at the first session -4.12 %, after 20.0 Gy - 3.61 %, patients with BSA > 1.92 m2: -2.06 % and -1.55 % respectively. After 20 Gy 34.8 % of patients with BSA < 1.92 m2 there was an increase in deviation from the planned dose, 65.2 % a decrease, while in 56.1 % of patients with BSA > 1.92 m2 there was an increase, and in 43.9 % - its reduction. With increasing BMI, the actual dose received on the rectal mucosa in the tenth session of irradiation is approaching the calculated one., Conclusions: When irradiated on the ROKUS-AM device, we did not find a probable dependence of the influence of the constitutional features of patients between the received and planned radiation dose. When treated with a Clinac 600 C, only body weight and body mass index at the tenth irradiation session have a likely effect on the dose differ- ence. Therefore, issues related to the individual approach to the treatment of uterine cancer, depending on anthro- pometric data is an urgent problem of modern radiotherapy., (O. M. Sukhina, A. S. Simbirova, V. S. Sukhin.)

Background: The dose distribution of heavy ions at the edge of the target region will have a steep decay during radiotherapy, which can better protect the surrounding organs at risk., Objective: To analyze the dose decay gradient at the back edge of the target region during heavy ion radiotherapy., Methods: Treatment planning system (TPS) was employed to analyze the dose decay at the edge of the beam under different incident modes and multiple dose segmentation conditions during fixed beam irradiation. The dose decay data of each plan was collected based on the position where the rear edge of the beam began to fall rapidly. Uniform scanning mode was selected in heavy ion TPS. Dose decay curves under different beam setup modes were drawn and compared., Results: The dose decay data analysis showed that in the case of single beam irradiation, the posterior edge of the beam was 5 mm away, and the posterior dose could drop to about 20%. While irradiation in opposite direction, the posterior edge of the beam was 5 mm away, and the dose could drop to about 50%. In orthogonal irradiation of two beams, the posterior edge of the beam could drop to about 30-38% in a distance of 5 mm. Through the data analysis in the TPS, the sharpness of the dose at the back edge of the heavy ion beam is better than that at the lateral edge, but the generated X-ray contamination cannot be ignored., Conclusions: The effect of uneven CT value on the dose decay of heavy ion beam should also be considered in clinical treatment., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © 2021 Xiaoyun Ma et al.)

Background: Patients with metastatic cancer referred to radiation oncology have diverse prognoses and there is significant interest in personalizing treatment. We hypothesized that patients selected for higher biologically equivalent doses have improved overall survival., Methods: The study population consists of 355 consecutive adult patients with distant metastases treated by a single radiation oncologist from 2014 to 2018. The validated NEAT model was used to prospectively stratify patients into four distinct cohorts. Radiation dose intensity was standardized using the equivalent dose in 2 Gy fractions (EQD2) model with an α/β of 10. Radiation dose intensity on survival was assessed via Cox regression models and propensity score match pairing with Kaplan-Meier analysis., Results: The median survival was 9.3 months and the median follow-up for surviving patients was 18.3 months. The NEAT model cohorts indicated median survivals of 29.5, 11.8, 4.9, and 1.8 months. Patients receiving an EQD2 of ≥40 Gy had a median survival of 16.0 months versus 3.8 months for patients receiving an EQD2 of <40 Gy (p < 0.001). On multivariable analysis, performance status, primary tumor site, radiation dose intensity, albumin, liver metastases, and number of active tumors were all independent predictors of survival (p < 0.05 for all). Propensity score matching was performed for performance status, albumin, number of active tumors, primary tumor site, and liver metastasis, finding higher EQD2 to remain significantly associated with improved survival within the matched cohort (p = 0.004)., Conclusion: Higher radiation dose intensity was used in patients with better prognosis and was associated with improved survival for patients with metastatic disease., (© 2021 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Introduction: We present a mathematical method to adjust the leaf end position for dose calculation correction in the carbon ion radiation therapy treatment planning system., Methods and Materials: A straggling range algorism of 400 MeV/n carbon ion beam in nine different multileaf collimator (MLC) materials was conducted to calculate the dose 50% point to derive the offset corrections in the carbon ion treatment planning system (ciPlan). The visualized light field edge position in the treatment planning system is denoted as X tang.p , and MLC position ( X mlc.p ) is defined as the source to leaf end midpoint projection on axis for monitor unit calculation. The virtual source position of energy at 400 MeV/n and straggling range in MLC at different field sizes were used to calculate the dose 50% position on axis. On-axis MLC offset (correction) could then be obtained from the position corresponding to 50% of the central axis dose minus the X mlc.p ., Results: The exact MLC position in the carbon ion treatment planning system can be used as an offset to do the correction. The offset correction of pure tungsten is the smallest among the others due to its shortest straggling range of carbon ion beam in MLC. The positions of 50% dose of all MLC materials are always located in between X tang.p and X mlc.p under the largest field of 12 cm by 12 cm., Conclusions: MLC offset should be adjusted carefully at different field sizes in the treatment planning systems especially of its small penumbra characteristic in the carbon ion beam. It is necessary to find out the dose 50% position for adjusting MLC leaf edge on-axis location in the treatment planning system to reduce dose calculation error., Competing Interests: There are no actual or potential conflicts of interest in this study., (Copyright © 2021 Yan-Shan Zhang et al.)

Objectives: Target volume delineation (TVD) has been identified as a weakness in the accuracy of radiotherapy, both within and outside of clinical trials due to the intra/interobserver variations affecting the TVD quality. Sources of variations such as poor compliance or protocol violation may have adverse effect on treatment outcomes. In this paper, we present and describe the FIELD RT software developed for the ARENA project to improve the quality of TVD through qualitative and quantitative feedbacks and individual and personalized summary of trainee"s performance., Methods: For each site-specific clinical case included in the FIELD RT software, reference volumes, minimum and maximum "acceptable" volumes and organ at risk were derived by outlines of consultants and senior trainees. The software components currently developed include: (a) user-friendly importing interface (b) analysis toolbox to compute quantitative and qualitative (c) visualiser and (d) structured report generator for personalised feedback. The FIELD RT software was validated by comparing the performance of 63 trainees and by measuring performance over time. In addition, a trainee evaluation day was held in 2019 to collect feedback on FIELD RT ., Results: Results show the trainees' improvement when reoutlining a case after reviewing the feedback generated from the FIELD RT software. Comments and feedback received after evaluation day were positive and confirmed that FIELD RT can be a useful application for training purposes., Conclusion: We presented a new open-source software to support education in TVD and ongoing continuous professional development for clinical oncology trainees and consultants. ARENA in combination with FIELD RT implements site-specific modules with reference target and organs at risk volumes and automatically evaluates individual performance using several quantitative and qualitative feedbacks. Pilot results suggests this software could be used as an education tool to reduce variation in TVD so to guarantee high quality in radiotherapy., Advances in Knowledge: FIELD RT is a new easy and free to use software aiming at supporting education in TVD and ongoing continuous professional development. The software provides quantitative/qualitative feedback and an exportable report with an individual and personalised summary of trainee's performance.

Aim: Stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) are essential tools in radiation oncology. In Spain, the use of these techniques continues to grow as older linear accelerators (linacs) are replaced with modern equipment. However, little is known about inter-centre variability in prescription and dose heterogeneity limits. Consequently, the SBRT-Spanish Task Group (SBRT-SG) of the Spanish Society of Radiation Oncology (SEOR) has undertaken an initiative to assess prescription and homogeneity in SRS/SBRT treatment. In the present study, we surveyed radiation oncology (RO) departments to obtain a realistic overview of prescription methods used for SBRT and SRS treatment in Spain., Methods: A brief survey was developed and sent to 34 RO departments in Spain, mostly those who are members of the SEOR SBRT-SG. The survey contained seven questions about the specific prescription mode, dose distribution heterogeneity limits, prescription strategies according to SRS/SBRT type, and the use of IMRT-VMAT (Intensity Modulated Radiation Therapy-Volumetric Modulated Arc Therapy)., Results: Responses were received from 29 centres. Most centres (59%) used the prescription criteria D 95%  ≥ 100%. Accepted dose heterogeneity was wide, ranging from 107 to 200%. Most centres used IMRT-VMAT (93%)., Conclusions: This survey about SRS/SBRT prescription and dose heterogeneity has evidenced substantial inter-centre variability in prescription criteria, particularly for intended and accepted dose heterogeneity. These differences could potentially influence the mean planning target volume dose and its correlation with treatment outcomes. The findings presented here will be used by the SEOR SBRT-SG to develop recommendations for SRS/SBRT dose prescription and heterogeneity., (© 2021. Federación de Sociedades Españolas de Oncología (FESEO).)

In boron neutron capture therapy, the total absorbed dose is the sum of four dose components with different relative biological effectiveness (RBE): boron dose, "nitrogen" dose, fast neutron dose and γ-ray dose. We present a new approach for measuring the first three doses. In this work, we provide the details of this method of dose measurement and results when this proposed method is employed., (©2021 by Radiation Research Society. All rights of reproduction in any form reserved.)

Background: Hepatic metastases occur frequently in the context of many tumor entities. Patients with colorectal carcinoma have already developed liver metastases in 20% at the time of diagnosis, and 25-50% develop metastases in the further course of the disease and therapy. The frequent manifestation and the variable appearance of liver metastases result in an interdisciplinary challenge, regarding treatment management. The aim of this study was to evaluate high-precision stereotactic body radiotherapy (SBRT) for liver metastases., Methods: A cohort of 115 patients with 150 irradiated liver metastases was analyzed. All metastases were treated between May 2004 and January 2020 using SBRT. A contrast-enhanced computed tomography (CT) was performed in all patients for treatment planning, followed by image-guided high-precision radiotherapy using cone-beam CT. A median cumulative dose of 35 Gy and a median single dose of 7 Gy was applied., Results: Median OS was 20.4 months and median LC was 35.1 months with a 1-year probability of local failure of 18% (95%-CI: 12.0-24.3%). In this cohort, 18 patients were still alive at the time of evaluation. The median FU-time in total was 11.4 months and for living patients 26.6 months. 70.4% of patients suffered from acute toxicities. There were several cases of grade 1 and 2 toxicities, such as constipation (13.9%), nausea (24.4%), loss of appetite (7.8%), vomiting (10.4%), diarrhea (7.8%), and abdominal pain (16.5%). 10 patients (8.7%) suffered from grade 3 toxicities. Late toxicities affected 42.6% of patients, the majority of these affected the gastrointestinal system., Conclusion: SBRT is becoming increasingly important in the field of radiation oncology. It has evolved to be a highly effective treatment for primary and metastasized tumors, and offers a semi-curative treatment option also in the case of oligometastatic patients. Overall, it represents a very effective and well-tolerated therapy option to treat hepatic metastases. Based on the results of this work and the studies already available, high-precision radiotherapy should be considered as a valid and promising treatment alternative in the interdisciplinary discussion.

Total body irradiation (TBI) is a kind of external beam radiotherapy, used in conjunction with chemotherapy with the purpose of immunosuppression. Since the target in TBI is the whole body, so achieving uniform dose distribution throughout the entire body during TBI is necessary. As recommended by AAPM dose variation must be within ±10% of the prescription dose. With the evidences from literature there is limited substantiation to consider a treatment method better than others, but with regard to the size of the treatment room, workload of the radiotherapy department and prevalent technology used within each treatment department it is recommended to make the suitable and optimum method in each department. In this work, a review study was performed on different TBI techniques with the purpose of assessment and comparison of dose distribution homogeneity in these methods., (Copyright © 2020 Société française de radiothérapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.)

Objective: Data supporting dose escalation for node-positive cervical cancer are currently limited to small retrospective studies. The goal of this study was to assess whether radiation dose was associated with lymph node control or gastrointestinal toxicity in patients with node-positive cervical cancer., Methods: A total of 390 patients with carcinoma of the uterine cervix were treated between October 1997 and October 2017. Patients included in our analysis were those with squamous cell carcinoma or adenocarcinoma who were node-positive, treated definitively, and with at least one follow-up visit and post-treatment imaging scan. We excluded those without follow-up and those treated with palliative intent. All patients were treated with external beam radiation to pelvic±para-aortic fields with concurrent weekly cisplatin. All lymph nodes present at the time of treatment were stratified by size as <2 cm or ≥2 cm. Acute and late gastrointestinal toxicity were recorded for all patients., Results: A total of 77 patients with 206 lymph nodes were identified. Median stage at presentation was FIGO IIB. Thirteen patients underwent definitive surgical resection followed by adjuvant radiation, of which 12 were treated to doses ≤5040 (range 2700-5940) cGy. Sixty-four patients were treated with definitive chemoradiation, of which 42 (66%) received ≤5040 (range 4500-5040) cGy and 22 (34%) received >5040 (range 5300-6640) cGy. Patients with pre-chemoradiation lymph nodes ≥2 cm had inferior lymph node control compared with patients with pre-chemoradiation lymph node <2 cm at 12 months (77% vs 100%, p=0.002). Radiation dose >5040 cGy was not significantly associated with improved lymph node control compared with ≤5040 cGy when analyzing all patients (12 months, 100% vs 89%, p=0.112). In patients with pre-chemoradiation lymph nodes ≥2 cm, radiation dose >5040 cGy was associated with improved lymph node control (12 months, 100% vs 60%, p=0.020). Acute grade ≥2 gastrointestinal toxicity was not associated with radiation dose >5040 cGy (20% vs 13%, p=0.424). Two patients developed grade ≥2 late gastrointestinal toxicity, both of whom were treated to ≤5040 cGy., Conclusions: This series supports the role of dose escalation for patients with lymph nodes ≥2 cm. Dose escalation is associated with improved control in patients with larger lymph nodes, and is not associated with greater gastrointestinal toxicity., Competing Interests: Competing interests: None declared., (© IGCS and ESGO 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Elderly patients are often excluded from advanced treatments owing to clinical complexity or frailty. Magnetic resonance-guided radiotherapy (MRgRT) represents a new frontier of radiotherapy delivery that can play an important role in the management of these patients., Aim: To assess MRgRT feasibility in elderly patients, describe their compliance with this treatment, and provide a scoring system for elderly patient selection., Methods: Patients aged >75 years were enrolled. No restrictions on tumor site, staging, or treatment intent were applied. Patients underwent joint radiation oncology-geriatrics visits to assess the feasibility of MRgRT and to identify the most significant items (i.e. clinical variables) for the setup of a scoring system. The proposed scoring system was then internally validated on a prospectively enrolled cohort of elderly patients who were candidates for MRgRT., Results: Thirty patients were enrolled between February and March 2018. Their mean age was 81.4 ± 3.4 years (range 75-88). Radiotherapy intent was curative in 26 patients; 14 patients were considered frail at screening tests before radiotherapy. Twelve items were identified as clinically significant for the setup of the MASTER score (MRI-Guided Radiotherapy Selection Elderly Score) score. Validation of the score showed 100% reliability, with no patient discharged after selection., Conclusions: MRgRT appears to be feasible in elderly patients and the MASTER score is proposed to support clinical decision-making in recommending elderly patients for this technology.

Aims: To evaluate how common radiation therapy techniques perform in the setting of the new European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) delineation recommendations for immediate breast reconstruction (IBR)., Materials and Methods: Seven Danish radiation therapy centres and six international European centres participated in this project. Two breast cancer cases (one left-sided and one right-sided) with a retropectoral implant were chosen for radiation therapy planning using deep-inspiration breath-hold. Target volumes were delineated according to ESTRO-ACROP delineation recommendations. The centres were asked to plan the cases using any radiation therapy technique according to the Danish Breast Cancer Group plan objectives., Results: In total, 35 treatment plans were collected. Half of the submitted plans, for both the left-sided and the right-sided case, used the field-in-field (FiF) technique (nine for each), a quarter used volumetric arc radiation therapy (VMAT; five for right-sided, four for left-sided) and the remaining quarter was a mix of inverse intensity-modulated radiation therapy (IMRT), helicoidal therapy and hybrid (combined open fields and VMAT) techniques. Mean clinical target volume doses were in the range 99-102% of the prescribed dose. The median FiF mean heart dose (MHD) for right-sided radiation therapy was 1 Gy (range 0.8-3.7) and 5.2 Gy for left-sided radiation therapy (range 2.2-6.5). For right-sided radiation therapy, the median VMAT MHD was 3.42 Gy, for IMRT was 2.3 Gy and for helicoidal therapy was 5.1 Gy. For left-sided radiation therapy, the median VMAT MHD was 6.3 Gy, for IMRT was 7.8 Gy and for helicoidal therapy was 7.3 Gy., Conclusions: Different radiation therapy techniques could be used to plan radiation therapy in the setting of IBR. FiF provided good coverage with acceptable organ at risk doses. The best dose distribution results as a trade-off between the objectives of target volume coverage and high-dose organ at risk inclusion. The radiation therapy technique affects the interplay between these objectives., (Copyright © 2020 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background: Plastic scintillator detector (PSD) Exradin W1 has shown promising performance in small field dosimetry due to its water equivalence and small sensitive volume. However, few studies reported its capability in measuring fields of conventional sizes. Therefore, the purpose of this study is to assess the performance of W1 in measuring point dose of both conventional IMRT plans and VMAT SRS plans., Methods: Forty-seven clinical plans (including 29 IMRT plans and 18 VMAT SRS plans with PTV volume less than 8 cm 3 ) from our hospital were included in this study. W1 and Farmer-Type ionization chamber Exradin A19 were used in measuring IMRT plans, and W1 and microchamber Exradin A16 were used in measuring SRS plans. The agreement between the results of different types of detectors and TPS was evaluated., Results: For IMRT plans, the average differences between measurements and TPS in high-dose regions were 0.27% ± 1.66% and 0.90% ± 1.78% ( P = 0.056), and were -0.76% ± 1.47% and 0.37% ± 1.34% in low-dose regions ( P = 0.000), for W1 and A19, respectively. For VMAT SRS plans, the average differences between measurements and TPS were -0.19% ± 0.96% and -0.59% ± 1.49% for W1 and A16 with no statistical difference ( P = 0.231)., Conclusion: W1 showed comparable performance with application-dedicated detectors in point dose measurements for both conventional IMRT and VMAT SRS techniques. It is a potential one-stop solution for general radiotherapy platforms that deliver both IMRT and SRS plans.

Differentiated thyroid cancer (DTC) is the most common endocrine malignancy with a growing incidence worldwide. The initial conventional management is surgery, followed by consideration of 131 I treatment that includes three options. These are termed remnant ablation (targeting benign thyroid remnant), adjuvant (targeting presumed microscopic DTC) and known disease (targeting macroscopic DTC) treatments. Some experts mostly rely on clinicopathologic assessment for recurrence risk to select patients for the 131 I treatment. Others, in addition, apply radioiodine imaging to guide their treatment planning, termed theranostics (aka theragnostics or radiotheragnostics). In patients with low-risk DTC, remnant ablation rather than adjuvant treatment is generally recommended and, in this setting, the ATA recommends a low 131 I activity. 131 I adjuvant treatment is universally recommended in patients with high-risk DTC (a primary tumor of any size with gross extrathyroidal extension) and is generally recommended in intermediate-risk DTC (primary tumor >4 cm in diameter, locoregional metastases, microscopic extrathyroidal extension, aggressive histology or vascular invasion). The optimal amount of 131 I activity for adjuvant treatment is controversial, but experts reached a consensus that the 131 I activity should be greater than that for remnant ablation. The main obstacles to establishing timely evidence through randomized clinical trials for 131 I therapy include years-to-decades delay in recurrence and low disease-specific mortality. This mini-review is intended to update oncologists on the most recent clinical, pathologic, laboratory and imaging variables, as well as on the current 131 I therapy-related definitions and management paradigms, which should optimally equip them for individualized patient guidance and treatment., (© 2020 UICC.)

Prescription and delivery of protons are somewhat different compared to photons and may influence outcomes (tumour control and toxicity). These differences should be taken into account to fully exploit the clinical potential of proton therapy. Innovations in proton therapy treatment are also required to widen the therapeutic window and determine appropriate populations of patients that would benefit from new treatments. Therefore, strategies are now being developed to reduce side effects to critical normal tissues using alternative treatment configurations and new spatial or temporal-driven optimisation approaches. Indeed, spatiotemporal optimisation (based on flash, proton minibeam radiation therapy or hypofractionated delivery methods) has been gaining some attention in proton therapy as a mean of improving (biological and physical) dose distribution. In this short review, the main differences in planning and delivery between protons and photons, as well as some of the latest developments and methodological issues (in silico modelling) related to providing scientific evidence for these new techniques will be discussed., (Copyright © 2020 Société française de radiothérapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.)

Background: A significant proportion of lung cancer patients suffer from malignant airway obstruction (MAO). Palliative external beam radiotherapy (EBRT) is often used to control the symptoms caused by MAO. In this study, we report the effect of palliative EBRT on lung cancer with MAO and analyze the factors that influence it., Methods: This study included 75 patients with MAO in lung cancer who underwent palliative EBRT, between 2009 and 2018 and were analyzed retrospectively. Change of dyspnea, tumor response, and overall survival (OS) were recorded. Univariate and multivariate analyses were performed to determine the prognostic factors for treatment outcomes., Results: The median follow-up duration was 2.5 months, and median OS was 2.3 months. Out of 75 patients, dyspnea was improved in 46 patients (61.3%), and tumor was partially decreased in 39 patients (52%). Symptoms improved in all tumor responding patients. The symptom improvement was significantly affected by radiation dose and time to EBRT. The tumor response was significantly affected by pathology, radiation dose, and time to EBRT., Conclusions: Palliative EBRT is an effective and safe treatment option for patients with MAO in lung cancer. In particular, high-dose irradiation and prompt treatment can improve treatment results., Key Points: SIGNIFICANT FINDINGS OF THE STUDY: In MAO patients, tumor response is an important factor for resolving dyspnea and improving survival rate. In order to increase the tumor response, high-dose irradiation and prompt treatment after symptoms occur are necessary., What This Study Adds: Our study reported the effects of EBRT and prognostic factors in MAO patients. We emphasize that palliative EBRT is a relatively safe and effective treatment in MAO patients, which is a complement to previous studies., (© 2020 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.)

Intracavitary application of brachytherapy (BT) sources followed by external beam radiation is essential for the local treatment of carcinoma of the cervix, postate, and nasopharynx. Dose distribution of external beam radiation plus BT can be challenging for the planning system because of their dose calculation by 2 different treatment planning system (TPS). The aims of this study were to introduce a novel iterative method of dose calculation preformed in the Pinnacle plan and evaluate a combined dose distribution for external beam radiation and BT.Because it is often the goal of the planner to produce plan with uniform dose throughout the target volume and normal tissue, we present an Iridium-192 calculation program using American Association of Physicists in Medicine Task Group 43 formula and export it to other commercialized TPS though the combined dose distribution of external beam radiation and BT can be shown. To illustrate such an improved procedure, we present the treatment plans of 2 patients treated with external beam radiation plus BT.Dose distribution of the single BT source were calculated with the Plato post loading TPS and the program model, and the results of 2 methods were similar. A nasopharyngeal case and a cervical case were shown in Pinnacle with this program. The total dose distribution of BT combined with EBRT was showed in compute tomography images. And the corresponding dose volume histogram figures could be displayed correctly in Pinnacle TPS.We demonstrated a novel iterative method of dose calculation preformed in the Pinnacle plan to produce a combined dose distribution for external beam radiation and BT. We used it to evaluate the dose of target volume and normal tissues in the treatment of external beam radiation plus BT.

Purpose: Our purpose was to demonstrate the use of novel planning techniques in producing high-quality stereotactic radiosurgery (SRS) plans using a standard 5 mm multileaf collimator (MLC) and multiple isocenters delivered clinically at a local institution., Methods and Materials: Novel planning techniques consisted of offset isocenter, variable asymmetrical jaws, and Digital Imagine and Communications in Medicine (DICOM) edits to reduce leaf tip transmission, all with the aim of maximizing dose conformity. A local institution clinical cohort was planned (1-4 targets), and plan conformity metrics common to SRS were compared against conformity metrics from selected previous publications comparing Gamma Knife to linear accelerator SRS using high-definition MLC (2.5 mm). Additionally, local institution plan conformity metrics for 2 benchmark SRS planning cases (3 and 7 targets) were compared with metrics from other centers treating SRS clinically in England. Pretreatment quality assurance results, both point dose measurement and film analysis, are presented to demonstrate plan deliverability., Results: Clinical conformity metrics are shown to be comparable to previously published results using either Gamma Knife or linear accelerator with high-definition MLC. Metrics from benchmark planning cases are shown to be comparable and to have better prescription dose conformity than average nationally in England. Pretreatment quality assurance results demonstrate suitable plan deliverability., Conclusions: SRS planning using standard 5 mm MLC and multiple isocenters produces high-quality treatment plans for a limited number of targets with a high degree of dose conformity and dose fall off when employing novel planning techniques to compensate for MLC leaf size and multiple isocenters., (Copyright © 2020 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

Introduction: Protocols have been developed in our department with recommended dose constraints for organs at risk (OAR) for each tumour site receiving definitive radiotherapy. We have developed a colour coding system to indicate when constraints are meeting objectives (green), have minor variation from planning objectives (yellow) and have major variation from planning objectives (red). We performed a quality audit to assess adherence to the protocol and to determine the rate of acute and subacute toxicities., Methods: All definitive radiotherapy dose-volume histogram (DVH) reports generated in the first 6 months of 2017 at Liverpool and Macarthur cancer therapy centres were collected. For each radiotherapy group, the overridden dose constraints were evaluated and categorized to red and yellow. For all patients in our data set, follow-up documents/assessments were searched for grade 3 or higher acute or subacute radiotherapy toxicity and compared with those who had overridden dose constraints., Results: There were 210 (34%) plans accepted with at least one major variation and 161 (26%) plans with minor variation. Head and neck group had the most rate of major variations (77%). The best groups in adherence to protocol were lymphoma and breast groups. In general, grade 3 toxicity was observed in 1%, 4% and 9% of patients who were in green, yellow and red categories. Overall, we noted a correlation with grade 3 toxicities between acceptable plans (green) and ones with a minor or major variation (yellow or red) (1% vs. 7% P = 0.0001)., Conclusion: In conclusion this study showed an increased risk of higher grade toxicities when DVHs were beyond our departmental constraints using a 'Traffic Light System'. With this new colour coding system, we can facilitate auditing of the dose constraints in order to improve the quality of radiotherapy plans and potentially provide benchmarking for reducing toxicities in radiotherapy treatments., (© 2020 The Royal Australian and New Zealand College of Radiologists.)

Background: The IAEA/WHO postal dose audit programme has been operating since 1969 with the aim of improving the accuracy and consistency of dosimetry in radiotherapy in low-income and middle-income countries world-wide. This study summarises the 50 years' experience of audits and explores the quality of reference dosimetry in participating radiotherapy centres throughout the years. Material and methods: During the IAEA/WHO postal audits the dose determined from the mailed dosimeter is compared with that stated by the participant. Agreement to within ±5% is regarded acceptable whilst deviations outside ±5% limits trigger follow-up actions. Of particular interest in this study was the dependence of clinical dosimetry quality on factors related to the centre infrastructure and expertise in dosimetry of its staff. Results: The IAEA/WHO dose audit programme noted great increase in the overall percentage of acceptable results from about 50% in its early years to 99% at present, although there is some variability of results amongst participating countries. Whereas results for younger radiotherapy machines show the agreement rate between the measured and the stated doses well above 90%, for those over 20 years old the rate dropped to <80%. Linac dosimetry was always better than 60 Co dosimetry and multi-machine centres generally performed better than single machine centres equipped with cobalt alone. Second and subsequent participation in audits showed higher quality dosimetry than the first participation. The implementation of modern dosimetry protocols resulted in more accurate dosimetry than the use of the older protocols. Conclusions: Over the 50 years that the IAEA has accumulated dosimetry audit data, practices in radiotherapy centres have significantly improved. Higher quality dosimetry confirmed in audits is generally associated with better infrastructure and adequate dosimetry expertise of medical physicists in participating centres.

Purpose: In a single-institution phase II study, we evaluated the safety of a 5-day dose-equivalent neoadjuvant radiotherapy (RT) regimen for high-risk primary soft tissue sarcoma., Patients and Methods: Patients received neoadjuvant RT alone (30 Gy in five fractions) to the primary tumor with standard margins. The primary endpoint was grade ≥2 late-radiation toxicity. Major wound complications, local recurrences, and distant metastases were also examined. In exploratory analysis, we evaluated germline biomarkers for wound toxicity and the effects of the study on treatment utilization., Results: Over 2 years, 52 patients were enrolled with median follow-up of 29 months. Seven of 44 evaluable patients (16%) developed grade ≥2 late toxicity. Major wound complications occurred in 16 of 50 patients (32%); a signature defined by 19 germline SNPs in miRNA-binding sites of immune and DNA damage response genes, in addition to lower extremity tumor location, demonstrated strong predictive performance for major wound complications. Compared with the preceding 2-year period, the number of patients treated with neoadjuvant RT alone at our institution increased 3-fold, with a concomitant increase in the catchment area., Conclusions: A shorter 5-day neoadjuvant RT regimen results in favorable rates of wound complications and grade ≥2 toxicity after 2-year follow-up. Five-day RT significantly increased utilization of neoadjuvant RT at our high-volume sarcoma center. With further validation, a putative germline biomarker for wound complications may guide safer RT utilization., (©2020 American Association for Cancer Research.)

The Canadian Cancer Society estimated that 220,400 new cases of cancer would be diagnosed in 2019. Of the affected patients, more than 60% will survive for 5 years or longer after their cancer diagnosis. Furthermore, nearly 40% will receive at least 1 course of radiotherapy (rt). Radiotherapy is used with both curative and palliative intent: to treat early-stage or locally advanced tumours (curative) and for symptom management in advanced disease (palliative). It can be delivered systemically (external-beam rt) or internally (brachytherapy). Although technique improvements have drastically reduced the occurrence of rt-related toxicity, most patients still experience burdensome rt side effects (seffs). Radiotherapy seffs are local or locoregional, and manifest in tissues or organs that were irradiated. Side effects manifesting within weeks after rt completion are termed "early seffs," and those occurring months or years after treatment are termed "late seffs." In addition to radiation oncologists, general practitioners in oncology and primary care providers are involved in survivorship care and management of rt seffs. Here, we present an overview of common seffs and their respective management: anxiety, depression, fatigue, and effects related to the head-and-neck, thoracic, and pelvic treatment sites., Competing Interests: CONFLICT OF INTEREST DISCLOSURES We have read and understood Current Oncology’s policy on disclosing conflicts of interest, and we declare that we have none., (2020 Multimed Inc.)

Background: In definitive chemoradiotherapy (CRTx) for esophageal cancer, a radiotherapy (RT) dose of 50.4 Gy in 28 fractions has been the standard in many countries, while 60 Gy in 30 fractions has been frequently used in Japan. To clarify the optimal RT dose in CRTx for esophageal cancer, we compared clinical outcomes with the two doses using data from the Comprehensive Registry of Esophageal Cancer in Japan by the Japan Esophageal Society (JES)., Methods: Of the patients enrolled in the registry for 2015-2017 surveys (patients treated between 2009 and 2011), 996 patients who received definitive CRTx with 50.4 Gy or 60 Gy for thoracic esophageal cancer were eligible for analysis., Results: The complete response (CR) rates in the 50.4 Gy and 60 Gy groups were 49.1% and 46.4%, respectively (p = 0.5851). The 5-year overall survival (OS) rates in the 50.4 Gy group and 60 Gy group for stages I, II/III and IV were 64.2% and 57.2%, 35.0% and 27.0%, and 18.0% and 15.3%, respectively. Since no significant difference was found between the two groups, the 50.4 Gy group was not inferior to the 60 Gy group with regard to OS., Conclusions: The analysis revealed that the 50.4 Gy group had a non-inferior outcome in comparison with the 60 Gy group for stages I, II/III and IV thoracic esophageal cancer. These results were obtained from a large database for the first time in Japan.

Purpose: Locoregionally recurrent breast cancer within a previously irradiated field requires weighing the benefits of reirradiation against the increased rates of toxicity. Here we evaluate the outcomes of patients treated with pulsed reduced dose rate (PRDR) radiation therapy with concurrent low-dose capecitabine as a method to increase the therapeutic ratio of re-treatment., Methods and Materials: Patients treated from November 2000 to June 1, 2018 with PRDR radiation therapy at University of Wisconsin were identified. Patients were re-treated to a median dose of 54 Gy (range, 37.5-66 Gy) using PRDR radiation therapy, delivering radiation at an apparent dose rate of 6.67 cGy/min to allow for increased sublethal damage repair of normal tissues. The median cumulative dose was 109.8 Gy. Twenty-two patients were treated with concurrent capecitabine, most frequently at 500 mg twice per day. The Kaplan-Meier method was used for survival analysis, and Cox regression analysis was used for univariate and multivariate analysis., Results: Forty-three patients were identified who underwent reirradiation for locoregionally recurrent invasive breast cancer, with a median follow-up of 20.5 months. Twenty-four patients had gross disease. Nineteen patients had simultaneous metastatic disease. The complete response rate was 83.3% in treated patients with gross disease. Locoregional recurrence-free survival was 81.3% and 73.8% for all patients at 1 and 2 years, respectively. Overall survival for patients with localized disease was 95.7% at 1 year and 91.1% at 2 years. The rate of acute grade 3 radiation dermatitis was 25.6% with no other acute grade 3 toxicities. Grade 3 late toxicity occurred in 18.6% of patients., Conclusions: PRDR radiation therapy with capecitabine was a well-tolerated and effective method for treating patients with recurrent breast cancer. Prospective studies are necessary to compare side effects and efficacy with conventional dose rate reirradiation and to evaluate the potential role for capecitabine in the recurrent setting., (Published by Elsevier Inc.)

Purpose: The heart has been identified as a potential significant organ at risk in patients with locally advanced non-small cell lung cancer treated with radiation. Practice patterns and radiation dose delivered to the heart in routine practice in academic and community settings are unknown., Methods and Materials: Between 2012 and 2017, 746 patients with stage III non-small cell lung cancer were treated with radiation within the statewide Michigan Radiation Oncology Quality Consortium (MROQC). Cardiac radiation dose was characterized, including mean and those exceeding historical or recently proposed Radiation Therapy Oncology Group and NRG Oncology constraints. Sites were surveyed to determine dose constraints used in practice. Patient-, anatomic-, and treatment-related associations with cardiac dose were analyzed using multivariable regression analysis and inverse probability weighting., Results: Thirty-eight percent of patients had a left-sided primary, and 80% had N2 or N3 disease. Median prescription was 60 Gy (interquartile range, 60-66 Gy). Twenty-two percent of patients were prescribed 60 Gy in 2012, which increased to 62% by 2017 (P < .001). Median mean heart dose was 12 Gy (interquartile range, 5-19 Gy). The volume receiving 30 Gy (V30 Gy) exceeded 50% in 5% of patients, and V40 Gy was >35% in 3% of cases. No heart dose constraint was uniformly applied. Intensity modulated radiation therapy (IMRT) usage increased from 33% in 2012 to 86% in 2017 (P < .001) and was significantly associated with more complex cases (larger planning target volume, higher stage, and preexisting cardiac disease). In multivariable regression analysis, IMRT was associated with a lower percent of the heart receiving V30 Gy (absolute reduction = 3.0%; 95% confidence interval, 0.5%-5.4%) and V50 Gy (absolute reduction = 3.6%; 95% confidence interval, 2.4%-4.8%) but not mean dose. In inverse probability weighting analysis, IMRT was associated with 29% to 48% relative reduction in percent of the heart receiving V40-V60 Gy without increasing lung or esophageal dose or compromising planning target volume coverage., Conclusions: Within MROQC, historical cardiac constraints were met in most cases, yet 1 in 4 patients received a mean heart dose exceeding 20 Gy. Future work is required to standardize heart dose constraints and to develop treatment approaches that allow for constraints to be met without compromising other planning goals., (Copyright © 2019 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

Background: To evaluate the patterns of failure in patients treated for head and neck carcinoma of unknown primary and to discuss treatment practices concerning radiotherapy target volumes definition and dose prescription., Methods: Eleven patients presenting a locoregional recurrence after head and neck carcinoma of unknown primary treatment with curative-intent radiochemotherapy performed between 2007 and 2017 in the departments of radiation oncology of 2 French cancer institutes. Images of the computed tomography scan or the magnetic resonance imaging performed at the time of the recurrence were fused with those of the simulation computed tomography scan to delimit a volume corresponding to the recurrence and to define the area of relapse compared to the volumes treated., Results: Irradiation was unilateral in 6 cases and bilateral in 5 cases. The median time to onset of recurrence was 7.24 months (extreme 3-67.7 months). Six patients had only a neck node recurrence, 3 had a neck node and subsequent primary recurrence, and 1 had only a median subsequent primary recurrence. Only 1 patient had synchronous distance progression to local recurrence. All neck node recurrences were solitary and ipsilateral. The subsequent primary recurrences were in the oropharynx in 3 cases and in the contralateral oral cavity in one case. All neck node recurrences were into the irradiated volume. The subsequent primary recurrences were either within or in border of the irradiated volumes. The median of the mean dose, received by neck node recurrences, was 69.9 Gy and that of the mean dose, minimum dose, maximum dose, and dose received by 95% of the volume of recurrence was 66.7 Gy. For the primary relapses, the median of the mean dose was 52.1 Gy and that of the mean dose, minimum dose, maximum dose, and dose received by 95% of the volume of recurrence was 39.9 Gy., Conclusions: All local nodal recurrences occurred at sites that received high radiotherapy doses and doses received by sites of eventual failure did not vary significantly from sites that remain in control.

The goal in external beam radiotherapy (EBRT) for cancer is to maximize damage to the tumour while limiting toxic effects on the organs-at-risk. EBRT can be delivered via different modalities such as photons, protons and neutrons. The choice of an optimal modality depends on the anatomy of the irradiated area and the relative physical and biological properties of the modalities under consideration. There is no single universally dominant modality. We present the first-ever mathematical formulation of the optimal modality selection problem. We show that this problem can be tackled by solving the Karush-Kuhn-Tucker conditions of optimality, which reduce to an analytically tractable quartic equation. We perform numerical experiments to gain insights into the effect of biological and physical properties on the choice of an optimal modality or combination of modalities., (© The Author(s) 2018. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.)

Aims: The CHHiP trial investigated the use of moderate hypofractionation for the treatment of localised prostate cancer using intensity-modulated radiotherapy (IMRT). A radiotherapy quality assurance programme was developed to assess compliance with treatment protocol and to audit treatment planning and dosimetry of IMRT. This paper considers the outcome and effectiveness of the programme., Materials and Methods: Quality assurance exercises included a pre-trial process document and planning benchmark cases, prospective case reviews and a dosimetry site visit on-trial and a post-trial feedback questionnaire., Results: In total, 41 centres completed the quality assurance programme (37 UK, four international) between 2005 and 2010. Centres used either forward-planned (field-in-field single phase) or inverse-planned IMRT (25 versus 17). For pre-trial quality assurance exercises, 7/41 (17%) centres had minor deviations in their radiotherapy processes; 45/82 (55%) benchmark plans had minor variations and 17/82 (21%) had major variations. One hundred prospective case reviews were completed for 38 centres. Seventy-one per cent required changes to clinical outlining pre-treatment (primarily prostate apex and base, seminal vesicles and penile bulb). Errors in treatment planning were reduced relative to pre-trial quality assurance results (49% minor and 6% major variations). Dosimetry audits were conducted for 32 centres. Ion chamber dose point measurements were within ±2.5% in the planning target volume and ±8% in the rectum. 28/36 films for combined fields passed gamma criterion 3%/3 mm and 11/15 of IMRT fluence film sets passed gamma criterion 4%/4 mm using a 98% tolerance. Post-trial feedback showed that trial participation was beneficial in evolving clinical practice and that the quality assurance programme helped some centres to implement and audit prostate IMRT., Conclusion: Overall, quality assurance results were satisfactory and the CHHiP quality assurance programme contributed to the success of the trial by auditing radiotherapy treatment planning and protocol compliance. Quality assurance supported the introduction of IMRT in UK centres, giving additional confidence and external review of IMRT where it was a newly adopted technique., (Copyright © 2019 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Aims: To report long-term outcomes with dose-escalated, image-guided adaptive radiotherapy (ART) for bladder preservation in muscle-invasive bladder cancer (MIBC)., Materials and Methods: All MIBC patients receiving bladder-preserving ART at our institute from 2009 to 2018 were analysed. For ART, three anisotropic planning target volumes (PTV) were concentrically grown around the simulation bladder volume. A library of intensity-modulated radiotherapy plans was created for each patient. A total dose of 64 Gy in 32 fractions to the entire bladder and 55 Gy to pelvic nodes was planned, with 68 Gy to the tumour bed (2 Gy equivalent dose = 68.7 Gy, α/β = 10) as simultaneous integrated boost for solitary tumours. The most appropriate PTV encompassing the bladder ('plan-of-the-day') was chosen daily using on-board megavoltage imaging. Neoadjuvant and concurrent chemotherapy was prescribed for medically fit patients., Results: Of a total of 106 patients, most had T2 (68%) or T3 (19%) disease. Ninety-two patients (87%) completed 64 Gy to the whole bladder. Sixty-three patients (59%) received 68 Gy as tumour bed boost. Seventy-six per cent received concurrent weekly chemotherapy. At a median follow-up of 26 months, 3-year locoregional control, disease-free survival and overall survival were 74.3, 62.9 and 67.7%, respectively. Eighty-two per cent of patients retained disease-free bladder. Radiation Therapy Oncology Group grade III/IV acute genitourinary and gastrointestinal toxicities were 7.5% and 0%, respectively, and late genitourinary/gastrointestinal toxicities were 6.5% and 3.8%, respectively. Overall survival, disease-free survival, locoregional control and grade III/IV genitourinary/gastrointestinal toxicities did not differ significantly with dose escalation., Conclusion: Plan-of-the-day ART is clinically safe and effective for bladder preservation and can be implemented in routine clinical practice. A high bladder preservation rate is achievable without compromising on survival or toxicities. Dose escalation does not seem to affect outcomes., (Copyright © 2019 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background: Human Papillomavirus oropharyngeal carcinoma (HPVOPC) has better progression free (PFS) and overall survival (OS) than non-HPVOPC. Standard-dose chemoradiotherapy (sdCRT) results in significant acute toxicity and late morbidity. We hypothesized that after induction chemotherapy (IC), reduced dose chemoradiation (rdCRT) would result in equivalent PFS and OS compared to sdCRT plus IC in HPVOPC and would reduce toxicity., Methods: Patients with p16+, previously untreated, locally advanced HPVOPC and ≤20 pack years smoking history received 3 cycles of IC with docetaxel, cisplatin and fluorouracil (TPF). Clinical responders who were HPV positive by type-specific PCR were randomized 1:2 to sdCRT (7000 cGy) or rdCRT (5600 cGy) with weekly carboplatin. The endpoints of the study were 3 year PFS and OS., Results: 23 patients were enrolled, 22 were evaluable for TPF toxicity and 20 were randomized, 8 to sdCRT and 12 to rdCRT. Sixteen (80%) were HPV 16+ and 4 (20%) were other high risk (HR) variants. Fourteen (70%) had high risk features: T4, N2c, or N3. Median follow up was 56 months (range 42-70). Three-year PFS/OS for sdCRT and rdCRT are 87.5% vs 83.3% (log-rank test p = 0.85), respectively. All 3 failures are locoregional within 4 months of completion of CRT; 2 were in HR variants (50%)., Conclusions: rdCRT after IC resulted in similar PFS/OS compared sdCRT. These data support Phase 3 clinical trials of radiation dose reduction after IC as a treatment strategy in HPVOPC. Molecular HPV with variant testing and smoking history are necessary for de-escalation trials., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose: Tumor motion plays a key role in the safe delivery of stereotactic body radiation therapy (SBRT) for pancreatic cancer. The purpose of this study was to use tumor motion measured in patients to establish limits on motion magnitude for safe delivery of pancreatic SBRT and to help guide motion-management decisions in potential dose-escalation scenarios., Methods and Materials: Using 91 sets of pancreatic tumor motion data, we calculated the motion-convolved dose of the gross tumor volume, duodenum, and stomach for 25 patients with pancreatic cancer. We derived simple linear or quadratic models relating motion to changes in dose and used these models to establish the maximum amount of motion allowable while satisfying error thresholds on key dose metrics. In the same way, we studied the effects of dose escalation and tumor volume on allowable motion., Results: In our patient cohort, the mean (range) allowable motion for 33, 40, and 50 Gy to the planning target volume was 11.9 (6.3-22.4), 10.4 (5.2-19.1), and 9.0 (4.2-16.0) mm, respectively. The maximum allowable motion decreased as the dose was escalated and was smaller in patients with larger tumors. We found significant differences in allowable motion between the different plans, suggesting a patient-specific approach to motion management is possible., Conclusions: The effects of motion on pancreatic SBRT are highly variable among patients, and there is potential to allow more motion in certain patients, even in dose-escalated scenarios. In our dataset, a conservative limit of 6.3 mm would ensure safe treatment of all patients treated to 33 Gy in 5 fractions., (Copyright © 2019 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

FLASH radiotherapy (FLASH-RT) is a technology that could modify the way radiotherapy is delivered in the future. This technique involves the ultra-fast delivery of radiotherapy at dose rates several orders of magnitude higher than those currently used in routine clinical practice. This very short time of exposure leads to the striking observation of relative protection of normal tissues that are exposed to FLASH-RT as compared with conventional dose rate radiotherapy. Here we summarise the current knowledge about the FLASH effect and provide a synthesis of the observations that have been reported on various experimental animal models (mice, zebrafish, pig, cats), various organs (lung, gut, brain, skin) and by various groups across 40 years of research. We also propose possible mechanisms for the FLASH effect, as well as possible paths for clinical application., (Copyright © 2019 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Purpose: With external beam radiation therapy, uncertainties in treatment planning and delivery can result in an undesirable dose distribution delivered to the patient that can compromise the benefit of treatment. Techniques including geometric margins and probabilistic optimization have been used effectively to mitigate the effects of uncertainties. However, their broad application is inconsistent and can compromise the conclusions derived from cross-technique and cross-modality comparisons., Methods and Materials: Conventional methods to deal with treatment planning and delivery uncertainties are described, and robustness analysis is presented as a framework that is applicable across treatment techniques and modalities., Results: This report identifies elements that are imperative to include when conducting a robustness analysis and describing uncertainties and their dosimetric effects., Conclusion: The robustness analysis approach described here is presented to promote reliable plan evaluation and dose reporting, particularly during clinical trials conducted across institutions and treatment modalities., (Published by Elsevier Inc.)

Purpose of Review: The purpose of this study is to provide an overview on the methodologies, outcomes and clinical implications of studies that have investigated swallowing outcomes after head and neck cancer (HNC) treatment when reducing radiotherapy dose to specific dysphagia/aspiration-related structures (DARS)., Recent Findings: Overall, there is limited recent evidence, with a lack of high-quality studies, which examine the outcomes of DARS-optimized radiotherapy treatment. Large variations exist in the methodology of these studies in regards to which DARS are delineated and how swallowing outcomes are measured. Consequently, there is a wide range of dose limits recommended to a variety of DARS structures. Despite these limitations, there appears to be a general consensus that optimizing dose to the DARS will result in some reduction of dysphagia after radiotherapy without compromising on treatment to the tumour., Summary: More rigorous study must be completed to determine the true extent of clinical benefit from this practice. Institutions must take into consideration the limitations of the evidence as well as logistical costs of implementing this technique into practice. However, optimizing dose to the DARS appears to be a well-tolerated practice that may have substantial positive benefits for patients' swallowing function and quality of life after HNC treatment.

Purpose: The aim of this retrospective study was to evaluate the clinical outcome of a previously defined low-risk patient population with completely resected (R0) squamous cell carcinoma of the oral cavity, oropharynx, larynx (pT1-3, pN0-pN2b), hypopharynx (pT1-2, pN0-pN1), and the indication for postoperative radio(chemo)therapy., Patients and Methods: According to predefined criteria, 99 patients with head and neck squamous cell carcinoma (SCC) who were treated at our institution from January 1, 2005 to December 31, 2014, were available for analysis. The Kaplan-Meier method was used for calculating survival and incidence rates. For univariate comparative analysis, the log-rank test was used for analyzing prognostic clinicopathologic parameters., Results: Median follow-up was 67 months. Cumulative overall (OS) and disease-free survival (DFS) were 97.9%/94.7%/88.0% and 96.9%/92.6%/84.7% after 1, 2, and 5 years, respectively. Cumulative incidence of loco-regional recurrence (LRR), distant metastases (DM), and second cancer (SC) were 1.0%/1.0%/4.9%, 0.0%/3.4%/5.8%, and 2.1%/4.2%/13.1%, respectively. In univariate comparative analysis, location of the primary tumor in the oropharynx was a significant predictor for increased OS (p = 0.043) and DFS (p = 0.048)., Conclusion: Considering the low disease relapse rates and high rates of therapy-induced late side effects, as well as the increased risk of developing SC, a prospective multicentric trial investigating de-escalation of radiotherapy in this clearly defined low-risk patient population was started and is still recruiting patients (DIREKHT-Trial, NCT02528955).

Institutions' adherence to protocol, quality assurance, and radiation parameter reporting are key to adequately interpret and compare treatment outcomes in radiation oncology. In 2017, the editorial board for Veterinary Radiology & Ultrasound adapted author guidelines on "technical information for radiation therapy (RT)". These guidelines provide a framework to report the RT treatment process in manuscripts resulting from veterinary clinical trials. In spite of this framework, however, in implementing IMRT, we have identified different "interpretations" of the extended prescription and reporting recommendations of the International Commission on Radiation Units and Measurements (ICRU 83), even within our small team. In the following commentary review, we provide a short summary of various detailed aspects of the ICRU 83 recommended (IMRT) prescription and reporting, including (a) absorbed target dose specification and prescription, (b) homogeneity and conformity, and (c) reporting of absorbed dose in organs at risk. In particular, we want to share our thoughts on possible dangers of noncompliance in adhering to protocol, prescription, and reporting. As veterinary IMRT publications still sparsely adhere to the recommendations of the ICRU, we were motivated to summarize the recommendations to facilitate appropriate reporting for IMRT in future veterinary studies., (© 2019 American College of Veterinary Radiology.)

Background: Patients with multiple myeloma (MM) are living longer than ever before thanks to new therapies. As a consequence, radiation therapy (RT) is increasingly important in the management of bone lesions from MM. Current American Society for Radiation Oncology guidelines recommend greater usage of 8 Gy in 1 fraction for treatment of these lesions. The objective of this study is to analyze utilization of 8 Gy in 1 fraction for treatment of MM bone lesions in the United States utilizing the National Cancer Data Base (NCDB)., Materials and Methods: The NCDB was used to identify patients with MM treated with palliative RT for painful bony lesions in the period between 2004 and 2014. Utilization rate of RT in this patient population as well as single-fraction (SFRT) versus multiple-fraction RT (MFRT) was compared according to demographic, socioeconomic, and logistic details., Results: A total of 95,190 patients met our inclusion criteria. Of these, 10,261 (10.8%) patients received RT, and a total of 243 (2.4%) of these patients received SFRT over the 10-year period. There was an 11.73% annual increase (P = .0001) in SFRT utilization from 2004 to 2014. Older age, black race, longer distance from the treatment facility, lower degree of education, treatment at an academic or integrated healthcare network, worse comorbidities, and more recent diagnoses were all associated with increased usage of SFRT., Conclusion: SFRT for the management of MM painful bony metastases remains underutilized. Trends show that radiation oncologists do not appear to be changing their approach to treating this disease., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Inhomogeneities in radiotherapy dose distributions covering the vertebrae in children can produce long-term spinal problems, including kyphosis, lordosis, scoliosis, and hypoplasia. In the published literature, many often interrelated variables have been reported to affect the extent of potential radiotherapy damage to the spine. Articles published in the 2D and 3D radiotherapy era instructed radiation oncologists to avoid dose inhomogeneity over growing vertebrae. However, in the present era of highly conformal radiotherapy, steep dose gradients over at-risk structures can be generated and thus less harm is caused to patients. In this report, paediatric radiation oncologists from leading centres in 11 European countries have produced recommendations on how to approach dose coverage for target volumes that are adjacent to vertebrae to minimise the risk of long-term spinal problems. Based on available information, it is advised that homogeneous vertebral radiotherapy doses should be delivered in children who have not yet finished the pubertal growth spurt. If dose fall-off within vertebrae cannot be avoided, acceptable dose gradients for different age groups are detailed here. Vertebral delineation should include all primary ossification centres and growth plates, and therefore include at least the vertebral body and arch. For partial spinal radiotherapy, the number of irradiated vertebrae should be restricted as much as achievable, particularly at the thoracic level in young children (<6 years old). There is a need for multicentre research on vertebral radiotherapy dose distributions for children, but until more valid data become available, these recommendations can provide a basis for daily practice for radiation oncologists who have patients that require vertebral radiotherapy., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Data on the biology and radiosensitivity of human papillomavirus-related cancers have led many expert radiation oncologists to decrease the radiation dose to target areas in selected situations. At Memorial Sloan Kettering Cancer Center, we have altered our radiation guidelines to allow substantial dose reduction to elective treatment regions and to omit radiation completely in other regions that have historically been included in the elective treatment volume. Here we summarize our current dose prescriptions and briefly explain the rationale behind these choices, which we anticipate will change when additional data mature. These recommendations are based on the American Joint Committee on Cancer seventh edition TNM Staging System and applicable only to patients who receive concurrent platinum-based chemotherapy and in whom both p16 immunohistochemistry and human papillomavirus RNA in situ hybridization tests are positive., (Copyright © 2018 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

Aim: By necessity of dosimeters calibration for evaluating delivered dose accuracy to organs out of the radiation field in patients undergoing gamma knife radiosurgery, we calibrated thermoluminescence dosimeters in gamma knife and 60 Co instruments, and then, compared both results to investigate when one of these devices was out of reach, can we use one of this instruments instead of the ther., Materials and Methods: To individual calibration by 60 Co, thermoluminescent dosimeters (TLDs) were placed in a Perspex sheet with conditions of source-skin distance = 80 cm, field size = 10 cm × 10 cm, and dose = 100 cGy. For individual calibration by Gamma knife, TLDs placed in flat Perspex were located in a special sphere and were exposed with conditions of source to axis distance = 40 cm, field size = 18 mm, and dose = 100 cGy, and for group calibration, TLDs were divided into six groups and were exposed with doses of 0-1000 cGy in both devices., Results: According to Fisher's exact test, calculated P = 0.27, so the difference is not significant., Conclusions: The result showed despite differences in calibration conditions, 60 Co unit can be used to calibrate TLD dosimeter for estimating the accuracy of measurement of delivered dose to organs of patients undergoing Gamma Knife 4C radiosurgery treatment., Competing Interests: None

Purpose: The delineation of volumes of interest can be a source of significant interobserver variability. The purpose of this study was to improve the homogeneity of delineation between oncologist-radiotherapists in the territorial departments of Nord and Pas-de-Calais (France) through discussions of clinical cases and the adoption of common published reference documents., Materials and Methods: All eleven radiotherapy centres in the Nord and Pas-de-Calais departments of France participated. The localizations assessed to date included prostate, head and neck, breast and brain cancers. For each localization, the junior or senior physician(s) in charge of pathology delineated the volumes of interest according to their usual practices. Validated indices, including the Dice similarity coefficient, were used to quantify the delineation differences. The anonymized results were presented at two to three annual meetings. A second delineation of the clinical cases was then carried out to quantify homogenization. An evaluation of dosimetry practices was also conducted for prostate cancer. Wilcoxon assay matched data were used., Results: Our work showed either satisfactory delineation concordance after the initial assessment or improved delineation concordance. For prostate cancer, the Dice similarity coefficient values were greater than 0.6 initially in two of the three clinical cases. For head and neck cancers, a statistically significant improvement was observed for only one of the clinical target volumes. More than half of the Dice similarity coefficient values were greater than 0.6 in the first comparison. The study of clinical cases of breast cancer allowed a homogenization of the delineation of five of the six lymph node clinical target volumes. The dosimetry study of prostate cancer allowed for a homogenization of practices., Conclusion: This work makes it possible to harmonize the delineation practices around validated standards. An extension to the entire Hauts-de-France region is planned., (Copyright © 2018 Société française de radiothérapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.)

Aim: The purpose of this study is to measure radiation leakage of Siemens Primus Plus and Siemens Artiste linear accelerators in electron mode and to compare the leakage level with that recommended by the International Electrotechnical Commission (IEC) standard., Materials and Methods: In this assessment, Siemens Primus Plus linear accelerator with 10 cm × 10 cm, 15 cm × 15 cm, and 25 cm × 25 cm applicators was used. The radiation leakage in lateral and vertical directions was measured for Siemens Primus Plus and Siemens Artiste linear accelerators., Results: Data derived from radiation leakage measurement for Siemens Primus Plus and Siemens Artiste linear accelerators in lateral direction from the field edge and in vertical direction from the applicator were reported. The radiation leakage data were then compared with the IEC standard to evaluate in-air field leakage., Conclusion: Comparing the radiation leakage level from fields with the IEC standard for two applicators, the maximum that was occurred for 12 MeV electron beam and applicator size of 10 cm × 10 cm in Siemens Artiste linear accelerator was 2.3%, which is less than the IEC's recommended limit of 10%. It is concluded that the leakage amount is much less than the specified limit and that both of the linear accelerators have high level of safety. Considering the measurement stage, it also needs to be noted that the beam angle affected the radiation leakage level from field edge, and in 25° angle, it is higher than in 0° angle. Comparing radiation leakage from the right side of the field for the two linear accelerators, the amount of leakage for Siemens Primus Plus linear accelerator is more than Siemens Artiste linear accelerator., Competing Interests: None

Purpose: This article compares the dosimetric differences between jaw tracking and no jaw tracking technique in static intensity-modulated radiation therapy plans of large and small tumors., Methods: Eight plans with large tumor (nasopharyngeal carcinoma, volume range: 510.9 to 768.0 cm 3 ) and 8 plans with small tumor (single brain metastasis, volume range: 5.3 to 9.9 cm 3 ) treated with jaw tracking on Varian EDGE LINAC were chosen and recalculated with no jaw tracking to study the dosimetric differences. We compared the differences of organ-at-risk doses (Dmax, Dmean), monitor units, and γ passing rate of plan verification (3mm/3%, threshold 10%; 2mm/2%, threshold 10%) between the 2 techniques., Results: The organ-at-risk doses of nasopharyngeal carcinoma cases having jaw tracking are all less than those with no jaw tracking. The Dmax and Dmean of organ-at-risks reduced 0.61% to 17.65% and 2.17% to 19.32%, P < .05, respectively. In cases with single brain metastasis, the organ-at-risk doses with jaw tracking were also lower than no jaw tracking. The Dmax and Dmean of organ-at-risk doses reduced 0.84% to 1.52% and 0.90% to 1.86%, P < .05, respectively. The monitor units for the large tumor and small tumor were increased by 2.41% and 1.1%, respectively. The γ passing rates (3mm/3%, th10%; 2mm/2%, th10%) of nasopharyngeal carcinoma plans are 99.89% ± 0.06% (jaw tracking) versus 99.56% ± 0.19% (no jaw tracking; P = .127); 97.15% ± 0.98% (jaw tracking) versus 91.90% ± 1.40% (no jaw tracking; P = .000), and the γ passing rates (3mm/3%, th10%; 2mm/2%, th10%) of brain metastasis plans are 99.97% ± 0.05% (jaw tracking) versus 99.44% ± 1.24% (no jaw tracking; P = .251), 98.65% ± 1.27% (jaw tracking) versus 93.35% ± 2.72% (no jaw tracking; P = .000)., Conclusion: Jaw tracking can reduce the dose of organ-at-risks compared to no jaw tracking, and the effect is more significant for plans with large tumor. The γ passing rate of plans with jaw tracking is also higher than the plans with no jaw tracking. Although the monitor units in plans of jaw tracking will increase slightly, it is recommended to use jaw tracking in static intensity-modulated radiation therapy both in large and in small tumors.