MATERIALS/METHODS: A total of 10 patients with synchronous bilateral breast cancer who were treated with VMAT at our institution were retrospectively analyzed. Clinical target volume (CTV) included chest wall and regional nodes (supraclavicular fossa and internal mammary chain) and prescription dose was 40.05 Gy in 15 daily fractions. HT and IMPT plans were generated for each patient. Dose-volume statistics, including planning target volume (PTV) coverage and dose to OAR: lungs, heart, thyroid, spinal cord, brachial plexus and esophagus, were compared between modalities using a paired T-test.
RESULTS: Mean age of patients was 61 years (43-84). Majority of the patients (80%) were ER+ PR+ and HER2-. 40% of patients underwent breast reconstruction following surgery. All 3 techniques provided adequate target volume distribution and OAR sparing. Compared to VMAT and HT plans, IMPT had better heart and lung sparing effects, resulting in lower mean and V25 Gy heart dose; mean, V20 Gy and V5 Gy lung dose (p<0.0001). There was no significant difference in VMAT and HT plans for mean heart and lung dose. VMAT plans showed significantly lower V25 Gy heart dose on average (p = 0.04). V5 Gy lung dose was slightly lower in HT compared to VMAT plans, approaching statistical significance (p = 0.08). PTV coverage was adequate for all 3 techniques. All techniques fulfilled cord, esophagus, thyroid and brachial plexus constraints.
CONCLUSION: IMPT plans showed significantly better OAR sparing compared to photon techniques. All 3 techniques met OAR constraints, and resulted in adequate target volume coverage. As IMPT is significantly more costly than VMAT or HT techniques, appropriate patient selection is important to deliver treatment in the most resource-effective manner for patients who would derive the most benefit, for example those with young age or existing heart or lung comorbidities.
MATERIALS AND METHODS: Ninety-seven ROs were randomly assigned to either manual or AI-assisted contouring of eight OARs for two head-and-neck cancer cases with an in-between teaching session on contouring guidelines. Thereby, the effect of teaching (yes/no) and AI-assisted contouring (yes/no) was quantified. Second, ROs completed short-term and long-term follow-up cases all using AI assistance. Contour quality was quantified with Dice Similarity Coefficient (DSC) between ROs' contours and expert consensus contours. Groups were compared using absolute differences in medians with 95% CIs.
RESULTS: AI-assisted contouring without previous teaching increased absolute DSC for optic nerve (by 0.05 [0.01; 0.10]), oral cavity (0.10 [0.06; 0.13]), parotid (0.07 [0.05; 0.12]), spinal cord (0.04 [0.01; 0.06]), and mandible (0.02 [0.01; 0.03]). Contouring time decreased for brain stem (-1.41 [-2.44; -0.25]), mandible (-6.60 [-8.09; -3.35]), optic nerve (-0.19 [-0.47; -0.02]), parotid (-1.80 [-2.66; -0.32]), and thyroid (-1.03 [-2.18; -0.05]). Without AI-assisted contouring, teaching increased DSC for oral cavity (0.05 [0.01; 0.09]) and thyroid (0.04 [0.02; 0.07]), and contouring time increased for mandible (2.36 [-0.51; 5.14]), oral cavity (1.42 [-0.08; 4.14]), and thyroid (1.60 [-0.04; 2.22]).
CONCLUSION: The study suggested that AI-assisted contouring is safe and beneficial to ROs working in LMICs. Prospective clinical trials on AI-assisted contouring should, however, be conducted upon clinical implementation to confirm the effects.
METHODS: The agreement indices (or pass rates) for global and local gamma evaluation, maximum allowed dose difference (MADD) and divide and conquer (D&C) techniques were calculated using a selection of acceptance criteria for 429 patient-specific pretreatment quality assurance measurements. Regression analysis was used to quantify the similarity of behavior of each technique, to determine whether possible variations in sensitivity might be present.
RESULTS: The results demonstrated that the behavior of D&C gamma analysis and MADD box analysis differs from any other dose comparison techniques, whereas MADD gamma analysis exhibits similar performance to the standard global gamma analysis. Local gamma analysis had the least variation in behavior with criteria selection. Agreement indices calculated for 2%/2 mm and 2%/3 mm, and 3%/2 mm and 3%/3 mm were correlated for most comparison techniques.
CONCLUSION: Radiation oncology treatment centers looking to compare between different dose comparison techniques, criteria or lower dose thresholds may apply the results of this study to estimate the expected change in calculated agreement indices and possible variation in sensitivity to delivery dose errors.
METHODS: Dose measurement of a standard pear-shaped plan carried out in phantom to verify the MOSkin dose measurement accuracy. With MOSkin attached to the third diode, RP3 of the PTW 9112, both detectors were inserted into patients' rectum. The RP3 and MOSkin measured doses in 18 sessions as well as the maximum measured doses from PTW 9112, RPmax in 48 sessions were compared to the planned doses.
RESULTS: Percentage dose differences ΔD (%) in phantom study for two MOSkin found to be 2.22 ± 0.07% and 2.5 ± 0.07%. IVD of 18 sessions resulted in ΔD(%) of -16.3% to 14.9% with MOSkin and ΔD(%) of -35.7% to -2.1% with RP3. In 48 sessions, RPmax recorded ΔD(%) of -37.1% to 11.0%. MOSkin_measured doses were higher in 44.4% (8/18) sessions, while RP3_measured were lower than planned doses in all sessions. RPmax_measured were lower in 87.5% of applications (42/47).
CONCLUSIONS: The delivered doses proven to deviate from planned doses due to unavoidable shift between imaging and treatment as measured with MOSkin and PTW 9112 detectors. The integration of MOSkin on commercial PTW 9112 surface found to be feasible for rectal dose IVD during cervical HDR ICBT.
RESULTS: The PTV, hippocampus and hippocampal avoidance volumes ranges between 1.00 - 39.00 cc., 2.50 - 5.30 cc and 26.47 - 36.30 cc respectively. The mean hippocampus dose for the HSWBRT and HSWBRT and SIB plans was 8.06 Gy and 12.47 respectively. The max dose of optic nerve, optic chiasm and brainstem were kept below acceptable range of 37.5 Gy.
CONCLUSIONS: The findings from this dosimetric study demonstrated the feasibility and safety of treating limited brain metastases with HSWBRT and SIB. It is possible to achieve the best of both worlds by combining HSWBRT and SIB to achieve maximal local intracranial control while maintaining as low a dose as possible to the hippocampus thereby preserving memory and quality of life.
MATERIALS/METHODS: Multivariable models developed to predict atomised and generalised urinary symptoms, both acute and late, were considered for validation using a dataset representing 754 participants from the TROG 03.04-RADAR trial. Endpoints and features were harmonised to match the predictive models. The overall performance, calibration and discrimination were assessed.
RESULTS: 14 models from four publications were validated. The discrimination of the predictive models in an independent external validation cohort, measured using the area under the receiver operating characteristic (ROC) curve, ranged from 0.473 to 0.695, generally lower than in internal validation. 4 models had ROC >0.6. Shrinkage was required for all predictive models' coefficients ranging from -0.309 (prediction probability was inverse to observed proportion) to 0.823. Predictive models which include baseline symptoms as a feature produced the highest discrimination. Two models produced a predicted probability of 0 and 1 for all patients.
CONCLUSIONS: Predictive models vary in performance and transferability illustrating the need for improvements in model development and reporting. Several models showed reasonable potential but efforts should be increased to improve performance. Baseline symptoms should always be considered as potential features for predictive models.