BACKGROUND: Evidence suggests the bladder trigone to be a potential organ at risk (OAR) in predicting acute and late genitourinary (GU) side effects when treating prostate cancer with radiotherapy.
METHODS: A search of MEDLINE, Cinahl, EMBASE, PubMed, the Cochrane Database of Systematic Reviews and OpenGrey was conducted and no current or underway systematic reviews or scoping reviews on the topic were identified. A systematic literature review was carried out assessing the quality of this evidence. All evidence that prospectively or retrospectively reviewed radiotherapy or modelled radiotherapy dose to the bladder trigone were included. The search was conducted on the 8th July 2021 with 32 studies included in this review. This was repeated 10th June 2023 and two additional studies were identified. Any evidence published since this date have not been included and are a limitation of this review.
RESULTS: MRI imaging is recommended to assist in delineating the trigone which has been shown to have a high amount of inter-observer variability and the use of specific training may reduce this. Across all radiotherapy treatment modalities, trigone dose contributed to GU acute and late toxicity symptoms. Trigone motion is relative to prostate motion but further research is required to confirm if the prostate can be used as a reliable surrogate for trigone position. The dose tolerance given for specific trigone related toxicities is debated within the literature, and on analysis the authors of this review suggest bladder trigone dose limits: Dmean < 45.8 Gy, V61.0Gy < 40%, V59.8Gy < 25%, V42.5Gy-V41.0Gy < 91% and V47.4Gy-V43.2Gy < 91% with α/β of 3 Gy to reduce acute and late GU toxicities.
CONCLUSIONS: There is evidence to support further research into bladder trigone sparing radiotherapy to improve patient outcomes.
CONCLUSIONS: Using the bladder trigone as an organ at risk is possible and the authors are currently seeking funding for a feasibility trial to further investigate this.

OBJECTIVE: In radiotherapy it is often necessary to transfer a patient\'s DICOM (Digital Imaging and COmmunications in Medicine) dataset from one system to another for re-treatment, plan-summation or registration purposes. The aim of the study is to evaluate effects of dataset transfer between treatment planning systems.
METHODS: Twenty-five patients treated in a 0.35T MR-Linac (MRidian, ViewRay) for locally-advanced pancreatic cancer were enrolled. For each patient, a nominal dose distribution was optimized on the planning MRI. Each plan was daily re-optimized if needed to match the anatomy and exported from MRIdian-TPS (ViewRay Inc.) to Eclipse-TPS (Siemens-Varian). A comparison between the two TPSs was performed considering the PTV and OARs volumes (cc), as well as dose coverages and clinical constraints.
RESULTS: From the twenty-five enrolled patients, 139 plans were included in the data comparison. The median values of percentage PTV volume variation are 10.8 % for each fraction, while percentage differences of PTV coverage have a mean value of -1.4 %. The median values of the percentage OARs volume variation are 16.0 %, 7.0 %, 10.4 % and 8.5 % for duodenum, stomach, small and large bowel, respectively. The percentage variations of the dose constraints are 41.0 %, 52.7 % and 49.8 % for duodenum, stomach and small bowel, respectively.
CONCLUSIONS: This study has demonstrated a non-negligible variation in size and dosimetric parameters when datasets are transferred between TPSs. Such variations should be clinically considered. Investigations are focused on DICOM structure algorithm employed by the TPSs during the transfer to understand the cause of such variations.

BACKGROUND: Radiation therapy plays a pivotal role as the primary adjuvant treatment for esophageal cancer (EPC), emphasizing the critical importance of carefully balancing radiation doses to the target area and organs at risk in the radiotherapeutic management of esophageal cancer.
OBJECTIVE: This study aimed to explore the correlation between morphological parameters and dosimetric parameters of the heart and spinal cord in intermediate- and advanced-stage esophagus cancer to provide a reference for clinical treatment.
RESULTS: A total of 105 patients with intermediate- and advanced-stage EPC, who received treatment in our hospital from 2019 to 2021, were included. The morphological parameters were calculated by imaging. Intensity-modulated radiation therapy plan was executed at Raystation4.7. The PTV-G stood for the externally expanded planning target volume (PTV) of the gross tumor volume (GTV) and PTV-C for the externally expanded volume of the clinical target volume (CTV). The prescription dose of PTV-G and PTV-C was set as 60Gy/30F and 54Gy/30F, respectively. The linear regression model was used to analyze the correlation between morphologic parameters of EPC and dosimetric parameters of the heart and spinal cord. In 105 cases, the total lung length was correlated with the spinal cord maximum dose (D2 ). The heart mean doses (Dmean ) and heart V40 (the relative volume that receives 40 Gy or more) was correlated with PTV-G volume, PTV-G length; In middle- and upper-segment EPC cases, only the total lung volume was correlated with the spinal cord Dmean , spinal cord D2 , heart Dmean , and heart V40 ; In middle-stage EPC cases, the heart Dmean was correlated with the PTV-G volume, PTV-G length. The total lung length was correlated with the spinal cord D2 ; In middle- and lower-segment EPC, only the PTV-G volume and PTV-G length were correlated with the heart Dmean . All the aforementioned values were statistically significant.
CONCLUSIONS: Combined with the unsegmented tumor and different locations, the organ at risk dose was comprehensively considered.

MR-linac devices offer the potential for advancements in radiotherapy (RT) treatment of head and neck cancer (HNC) by using daily MR imaging performed at the time and setup of treatment delivery. This article aims to present a review of current adaptive RT (ART) methods on MR-Linac devices directed towards the sparing of organs at risk (OAR) and a view of future adaptive techniques seeking to improve the therapeutic ratio. This ratio expresses the relationship between the probability of tumor control and the probability of normal tissue damage and is thus an important conceptual metric of success in the sparing of OARs. Increasing spatial conformity of dose distributions to target volume and OARs is an initial step in achieving therapeutic improvements, followed by the use of imaging and clinical biomarkers to inform the clinical decision-making process in an ART paradigm. Pre-clinical and clinical findings support the incorporation of biomarkers into ART protocols and investment into further research to explore imaging biomarkers by taking advantage of the daily MR imaging workflow. A coherent understanding of this road map for RT in HNC is critical for directing future research efforts related to sparing OARs using image-guided radiotherapy (IGRT).

The use of stereotactic ablative radiotherapy (SABR) in the UK has expanded over the past decade, in part as the result of several UK clinical trials and a recent NHS England Commissioning through Evaluation programme. A UK SABR Consortium consensus for normal tissue constraints for SABR was published in 2017, based on the existing literature at the time. The published literature regarding SABR has increased in volume over the past 5 years and multiple UK centres are currently working to develop new SABR services. A review and update of the previous consensus is therefore appropriate and timely. It is hoped that this document will provide a useful resource to facilitate safe and consistent SABR practice.

Background Geometrical and anatomical variations occur during the brachytherapy of carcinoma cervix and dose optimization is necessary for every fraction of high‑dose rate intracavitary brachytherapy (HDR-ICBT) for carcinoma of the cervix. A single planned treatment is usually delivered for multiple fractions without consideration of inter-fractional applicator positioning variations and organ motion, which may lead to substantial differences between the planned and delivered doses. Aim and objectives This study was aimed at evaluating the inter-fractional variation in volume and radiation dose to organs at risk during ICBT for cervical cancer. Furthermore, the doses to high-risk clinical target volume (HRCTV) and the role of adaptive planning in ICBT were assessed. Materials and methods Twenty-two patients with carcinoma of the cervix Stage IB2-IVA receiving ICBT were enrolled in the study. All the patients were treated with ICBT four fractions in two applications. For the first application, magnetic resonance imaging-based planning was done, and for the next three fractions, computed tomography (CT) scans were done before every treatment fraction. The CT images were contoured and replanned by keeping the First (I) fraction of each application as the reference. Dose-volume histograms (DVH) were generated, and details of D2cc (DVH on a volume of 2cc) of bladder, rectum, and sigmoid colon (organs at risk-OAR) and D90 HRCTV (dose covering 90%) were documented. Results In patients receiving ICBT, variations in OAR D2cc ranged from 1.5 to 2.5Gy for the bladder (p- 0.001), from 2.0 to 3.2Gy (p-0.005) for the rectum and from 1.5 to 3.5Gy for the sigmoid colon (p 0.103). The p-value was significant for D2cc when compared with the OAR volume for the bladder and rectum in both applications, whereas it was not significant for the sigmoid colon. The percentage change in HRCTV coverage was 7% in the first application and by 16% in the second application because of adaptive planning. Conclusion Significant variations in doses received by D2cc of the bladder and rectum as well as significant improvement in HRCTV coverage between the fractions were observed because of replanning. Hence, image-guided HDR-ICBT should be incorporated with adaptive planning when delivering in multiple fractions.

Historically, respiratory induced motion has made renal radiotherapy difficult due to the potential risk of additional toxicities to the patient due to tumor movement. The use of deep inspiration breath holds (DIBH) in congruence with magnetic resonance guided radiotherapy (MRgRT) may be an effective method to manage tumor and organ at risk (OAR) motion and deliver radiation safer and more effectively. The purpose of this case study was to evaluate the effectiveness of DIBH in sparing radiation dose to colon and small bowel during MRgRT of right sided renal cell carcinoma (RCC). The goals were to reduce radiation dose to colon and small bowel during RCC treatment with these motion management techniques. A retrospective case study of a patient with oligoprogression in the postoperative renal fossa was found to be a candidate for DIBH using MRgRT. Treatment planning called for motion management and real-time imaging in order to safely treat the tumor volume. Results were evaluated by the achievement of specific dosimetric criteria and tolerances and the regression of disease in the renal fossa. The use of real-time imaging and simultaneous motion management proved to be effective tools for the treatment of RCC. This radiation therapy treatment resulted in the elimination of malignancy at the primary site of disease.

UNASSIGNED: Endovascular aortic repair (EVAR) is obviously less invasive than open aortic repair (OAR) for the treatment of infra-renal abdominal aortic aneurysm (AAA). However, it is not free of complications which can potentially result in severe morbidity or even mortality. The purpose of this study was to share our single-center experience with stent-graft related and systemic complications associated with EVAR.
UNASSIGNED: Patients with infra-renal AAA treated by elective and emergency EVAR between March 2014 and November 2020 were retrospectively identified. Demographic data, risk factors, American Society of Anesthesiologists (ASA) score, systemic complications, stent-graft related complications, surgical site complications, 30-day mortality, late EVAR related mortality, estimated blood loss, intensive care unit (ICU) length of stay (LOS), hospital LOS and follow-up durations were collected and analyzed.
UNASSIGNED: A total of 43 patients underwent EVAR during the period of study. There were 42 males (97.7%) and 1 female (2.3%). The mean age was 68.8 ± 6.2 years. Elective EVAR was performed in 36 (83.7%) and emergency EVAR in 7 (16.3%). Technical success was achieved in 42 patients (100%) with no conversion to OAR. Stent-graft related complications were (21.0%) endoleaks, (2.3%) graft limb occlusion, (0%) graft infection, and (2.3%) rupture-EVAR. Systemic complications were (2.3%) myocardial infarction (MI), (2.3%) stroke, (2.3%) spinal cord injury (SCI), (2.3%) respiratory failure, (19.0%) wound complications, and (2.3%) acute lower limb ischemia (ALI). The 30-day mortality was (2.3%) due to perioperative MI and the late graft related mortality was (2.3%) due to rupture-EVAR.
UNASSIGNED: EVAR showed a high technical success rate with no conversion to OAR. The most common complications were type II and type I endoleaks followed by graft limb occlusion. The 30-day mortality was 2.3% due to perioperative MI. Only one late stent-graft related mortality was registered due to rupture-EVAR.

UNASSIGNED: A better understanding of the organs-at-risk (OAR) dose metrics and the related toxicity induced by radiotherapy (RT) for left breast cancer (BC) will improve the quality of life. This study addressed the issue for left-BC patients treated with intensity-modulated radiotherapy (IMRT) compared to three-dimensional conformal radiotherapy (3D-CRT).
UNASSIGNED: Between 2012 and 2018, 308 left-BC patients underwent adjuvant RT at our hospital. Before June 2015, 134 patients were treated with 3D-CRT. Thereafter, 174 patients underwent IMRT. The patient\'s characteristics in the IMRT group did not significantly different compared to those in the 3D-CRT group.
UNASSIGNED: Among the total study population, the incidence of ≥grade 2 radiation dermatitis (RID) was 17.3%. Higher volumes receiving 105% (≥5.7%) and 107% (≥1%) of prescribed dose and 3D-CRT technique were associated with a higher risk of RID. Regarding lung toxicity, the mean lung dose (≥10.2Gy) and V20 (≥20%) of ipsilateral lung were significantly associated with the incidence of RT-induced pulmonary changes. By dosimetry analysis, IMRT achieved better dose conformity and delivered lower mean doses to heart and ipsilateral lung compared to 3D-CRT. Furthermore, propensity sore and multivariate analysis showed that IMRT technique helped to reduce RT-induced dermatitis and lung toxicity.
UNASSIGNED: Our data suggest that the volume of OAR exposed to higher doses is a predictor of RT-induced toxicity. Adjuvant RT with IMRT technique offered better dose conformity and spared high-dose levels to OARs to reduce radiation-related morbidity for BC patients.

Manual delineation of clinical target volumes (CTVs) and organs at risk (OARs) is time-consuming, and automatic contouring tools lack clinical validation. We aimed to construct and validate the use of convolutional neural networks (CNNs) to set better contouring standards for rectal cancer radiotherapy.
We retrospectively collected and evaluated computed tomography (CT) scans of 199 rectal cancer patients treated at our hospital from February 2018 to April 2019. Two CNNs-DeepLabv3+ for extracting high-level semantic information and ResUNet for extracting low-level visual features-were used for the CTV and small intestine contouring, and bladder and femoral head contouring, respectively. Contouring quality was compared using the paired t test. Five-point objective grading was performed independently by two experienced radiation oncologists and verified by a third. The CNN manual correction time was recorded.
CTVs calculated using DeepLabv3+ (CTVDeepLabv3+) had significant quantitative parameter advantages over CTVResUNet (volumetric Dice coefficient, 0.88 vs 0.87, P = 0.0005; surface Dice coefficient, 0.79 vs 0.78, P = 0.008). Among 315 graded cases, DeepLabv3+ obtained the highest scores with 284 cases, consistent with the objective criteria, whereas CTVResUNet had the minimum mean manual correction time (7.29 min). DeepLabv3+ performed better than ResUNet for small intestine contouring and ResUNet performed better for bladder and femoral head contouring. The manual correction time for OARs was <4 min for both models.
CNNs at various feature resolution levels well delineate rectal cancer CTVs and OARs, displaying high quality and requiring shorter computation and manual correction time.