PURPOSE:Swallowing dysfunction after radiotherapy (RT) is often linked to pharyngeal mucosal damage. This study aimed to develop a dysphagia-optimized knowledge-based planning (DO-KBP) model by incorporating individual pharyngeal constrictors (DO-KBP) into an existing model, which was based on a conventional approach of including pharynx as a single structure during treatment planning (P-KBP). MATERIALS AND METHODS:The P-KBP model was trained on 175 head and neck cases with the pharynx contoured as a single organ. The DO-KBP model included 36 additional oropharynx cases (∼20% increase) with individual pharyngeal constrictors delineated. Both models were evaluated on 25 test patients. Treatment plans generated by each model were normalized to planning-target-volume (PTV) coverage (D95%), and dosimetric parameters were compared using two-tailed paired t-tests. A blind physician review assessed clinical preference. RESULTS:The DO-KBP model was able to significantly reduce the mean dose to the inferior constrictor (36.52 ± 9.87 Gy to 19.52 ± 6.23 Gy) and superior/middle constrictors (51.89 ± 6.31 Gy to 47.46 ± 6.12 Gy) (p < 0.05) with the addition of 36 high-quality treatment plans. Though statistically significant increases in mean dose were observed for the spinal cord PRV (D0.03cc), cochlea, mandible, and left brachial plexus with the DO-KBP model, these differences were small in magnitude and remained within clinical goals. However, these differences were small in magnitude and remained within clinical goals. Plan homogeneity was equivalent (HI = 0.09). The DO-KBP plans were preferred in blinded review. CONCLUSION:Targeted addition of a small number of cases with individually contoured constrictors to an existing model significantly improved sparing of swallowing structures, without compromising overall plan quality or increasing organs-at-risk (OAR) doses beyond clinical thresholds, highlighting that modest, focused data augmentation can yield clinically meaningful gains.

BACKGROUND:Volumetric modulated arc therapy (VMAT) is increasingly used for breast and chest wall (CW) treatment with regional nodal irradiation (RNI) because of its ability to sculpt dose around complex target volumes. However, VMAT can increase low-dose radiation to surrounding normal tissues and particularly increase cardiac dose. PURPOSE:To evaluate the dosimetric impact of a strategic aperture-restricted beam geometry, compared with traditional open-field geometry in VMAT planning for comprehensive left-sided breast/CW irradiation with RNI across three linac platforms. The impact of convergence mode settings was also investigated. METHODS:Fourteen patients with left-sided breast/CW irradiation including comprehensive RNI were retrospectively included. For each patient, a patient-specific optimization template with a prescription of 40.05 Gy in 15 fractions was applied across three linac platforms (Varian TrueBeam, Varian Halcyon, and Elekta Versa HD), using two beam geometries: an open-field approach, in which field sizes fully encompassed the targets, and an aperture-restricted approach, in which the deep field border was limited to reduce beam entry to the heart and ipsilateral lung. Jaw tracking was enabled on the TrueBeam and Versa HD linacs. Each plan was also evaluated across three convergence modes ("Off," "On," and "Extended"), resulting in 18 plans per patient. All plans were normalized such that 95% of the breast/CW planning target volume received 95% of the prescription dose. Dosimetric endpoints include mean heart dose, ipsilateral lung V17Gy, contralateral lung V4Gy, and contralateral breast/CW V5Gy. Total monitor units (MUs) were evaluated, and patient-specific quality assurance (PSQA) was performed for the three highest-MU plans on each linac platform. Paired tests were used to compare across plans. RESULTS:Target coverage was maintained after plan normalization. Aperture-restricted VMAT significantly reduced mean heart dose compared with open-field geometry across all linac platforms and convergence modes. The proportion of plans exceeding mean heart dose of 4 Gy was substantially lower with aperture-restricted geometry compared to open-field plans (2.4% vs 26.2%). The largest reduction in mean heart dose was observed with the "Off" convergence mode, decreasing from 4.20 to 2.71 Gy on TrueBeam, 3.32 to 2.58 Gy on Halcyon, and 3.97 to 2.84 Gy on Versa HD. Ipsilateral lung V17Gy was also significantly reduced with aperture-restricted beam geometry, with only one exception on Halcyon using the "Extended" mode. No significant differences were observed in contralateral lung V4Gy, although contralateral breast/CW V5Gy increased significantly, representing a dosimetric tradeoff associated with the aperture-restricted geometry. Aperture-restricted beam geometry significantly increased MUs; however, PSQA passed for the three highest-MU plans on each linac platform according to our clinical criteria. Additionally, more extensive convergence modes were associated with improved plan quality, particularly in reducing hotspot dose (D0.1cc) and enhancing cardiac and ipsilateral lung sparing. CONCLUSIONS:Aperture-restricted beam geometry significantly reduced mean heart dose and ipsilateral lung dose while maintaining target coverage across all three linac platforms, supporting its potential clinical value in VMAT planning for comprehensive left-sided breast/CW irradiation with RNI, albeit with increased contralateral breast/CW dose. When combined with a more extensive convergence mode, overall plan quality was further improved.

Purpose: We evaluated changes in radiation therapy target volume and acute toxicity using Ga-68-prostate specific membrane antigen (PSMA) versus F-18-fluciclovine positron emission tomography (PET)/computed tomography in postprostatectomy patients with biochemical recurrence. We hypothesized that both fluciclovine and PSMA-guided radiation therapy would (1) significantly change pre-PET radiation therapy volumes and (2) show similar toxicity. Methods and Materials: We performed an institutional review board-approved, randomized trial comparing fluciclovine (Arm 1) and PSMA (Arm 2)-guided postprostatectomy radiation therapy in patients with detectable prostate-specific antigen after prostatectomy. Treatment volumes were rigidly defined based on PET, and simultaneous integrated boosts to PET uptake in the prostate bed (70.2-76.0 Gy) or pelvis (54.0-56.0 Gy) were allowed. Clinical target volumes (CTVs) included: prostate bed (CTVPB); pelvic lymph nodes (CTVPLV); and volumetric constraints for bladder(-CTV) and rectum. Acute genitourinary and gastrointestinal (GI) toxicity (per Common Terminology Criteria for Adverse Events v5.0) was assessed <90 days from treatment. Results: In total, 140 patients were enrolled with 70 randomized to each arm; 11 Arm 1 and 10 Arm 2 patients did not receive radiation on study and were excluded. Fluciclovine and PSMA incorporation increased both CTVPB and CTVPLV (P < .01). More fluciclovine patients received prostate bed boosts (45 of 59 patients vs 26 of 60 patients; P < .01), but there was no difference in proportion receiving pelvic nodal boosts (10 of 15 patients vs 9of 16 patients, fluciclovine vs PSMA; P = .97). Dose constraints were met for most patients. Rates of grade 2 genitourinary (17.0% vs 6.7%, fluciclovine vs PSMA; P = .15) and GI (5.1% vs 1.7%, fluciclovine vs PSMA; P = .47) toxicity were low, with no grade 3+ events. Higher rectal and bladder dose metrics correlated with GI toxicity (P < .05), but use of simultaneous integrated boosts was not associated with acute toxicity. Conclusions: Although both PSMA and fluciclovine use modestly increased target volumes, significantly more fluciclovine patients received prostate bed boosts. Planning directives were met for most patients, and acute toxicity was mild in both Arms. Analysis of biochemical control, late toxicity, and patient-reported outcomes are forthcoming.

Background PET with gallium 68 (68Ga) prostate-specific membrane antigen (PSMA)-11 and fluorine 18 (18F) fluciclovine has influenced salvage radiation therapy (sRT) planning in postprostatectomy biochemical recurrence. Purpose To assess the comparative impact of 18F-fluciclovine and 68Ga-PSMA-11 PET/CT on sRT changes in postprostatectomy biochemical recurrence. Materials and Methods In this secondary analysis of a prospective randomized controlled trial, men with detectable prostate-specific antigen (PSA) levels after prostatectomy were randomly assigned to undergo 18F-fluciclovine PET/CT (arm A) or 68Ga-PSMA-11 PET/CT (arm B) between May 2019 and May 2023. The Clopper-Pearson binomial method was used to evaluate decision changes on whether to offer radiation therapy (RT) and to which field (with or without boost) between the pre- and post-PET time points in each arm, and to compare decision changes between the arms. Results A total of 140 eligible participants (age range, 47-83 years) were randomly assigned 1:1 to arm A (mean age, 63 years ± 8 [SD]; median pre-RT PSA level, 0.27 ng/mL) or to arm B (mean age, 65 years ± 8; median pre-RT PSA, 0.35 ng/mL). Six participants (five in the 18F-fluciclovine group and one in the 68Ga-PSMA-11 group) withdrew from the trial before undergoing PET/CT. Overall sRT decision changes occurred in 19 of 65 participants (29%) in arm A (P < .001) and 29 of 69 participants (42%) in arm B (P < .001), but there was no evidence of a difference between arms (P = .12). Among participants for whom the final decision was to offer them sRT, treatment field (and/or boost) changes occurred in 43 of 60 participants (72%) in arm A (P < .001) and 33 of 61 participants (54%) in arm B (P < .001) and were more likely with 18F-fluciclovine PET/CT than with 68Ga-PSMA-11 PET/CT (P = .046). Conclusion In postprostatectomy biochemical recurrence, the use of 18F-fluciclovine and 68Ga-PSMA-11 for PET/CT-guided sRT planning resulted in substantial treatment decision changes, but there was no difference in the likelihood of a decision change between the two radiotracers. Treatment field (and/or boost) changes were more likely with 18F-fluciclovine PET/CT than with 68Ga-PSMA-11 PET/CT. Clinical trial registration no. NCT03762759 © RSNA, 2026 Supplemental material is available for this article. See also the editorial by Iravani in this issue.

Molecular imaging with 18 F-fluciclovine or 68 Ga–prostate-specific membrane antigen–11 had a substantial effect on PET/CT-guided salvage radiotherapy planning in participants with prostate cancer recurrence after prostatectomy.

Purpose We evaluated changes in radiation therapy target volume and acute toxicity using 68Ga-prostate specific membrane antigen (PSMA) versus 18F-fluciclovine positron emission tomography (PET)/computed tomography in postprostatectomy patients with biochemical recurrence. We hypothesized that both fluciclovine and PSMA-guided radiation therapy would (1) significantly change pre-PET radiation therapy volumes and (2) show similar toxicity. Methods and Materials We performed an institutional review board-approved, randomized trial comparing fluciclovine (Arm 1) and PSMA (Arm 2)-guided postprostatectomy radiation therapy in patients with detectable prostate-specific antigen after prostatectomy. Treatment volumes were rigidly defined based on PET, and simultaneous integrated boosts to PET uptake in the prostate bed (70.2-76.0 Gy) or pelvis (54.0-56.0 Gy) were allowed. Clinical target volumes (CTVs) included: prostate bed (CTVPB); pelvic lymph nodes (CTVPLV); and volumetric constraints for bladder(-CTV) and rectum. Acute genitourinary and gastrointestinal (GI) toxicity (per Common Terminology Criteria for Adverse Events v5.0) was assessed <90 days from treatment. Results In total, 140 patients were enrolled with 70 randomized to each arm; 11 Arm 1 and 10 Arm 2 patients did not receive radiation on study and were excluded. Fluciclovine and PSMA incorporation increased both CTVPB and CTVPLV (P < .01). More fluciclovine patients received prostate bed boosts (45 of 59 patients vs 26 of 60 patients; P < .01), but there was no difference in proportion receiving pelvic nodal boosts (10 of 15 patients vs 9of 16 patients, fluciclovine vs PSMA; P = .97). Dose constraints were met for most patients. Rates of grade 2 genitourinary (17.0% vs 6.7%, fluciclovine vs PSMA; P = .15) and GI (5.1% vs 1.7%, fluciclovine vs PSMA; P = .47) toxicity were low, with no grade 3+ events. Higher rectal and bladder dose metrics correlated with GI toxicity (P < .05), but use of simultaneous integrated boosts was not associated with acute toxicity. Conclusions Although both PSMA and fluciclovine use modestly increased target volumes, significantly more fluciclovine patients received prostate bed boosts. Planning directives were met for most patients, and acute toxicity was mild in both Arms. Analysis of biochemical control, late toxicity, and patient-reported outcomes are forthcoming.

This study characterizes lung stereotactic body radiation therapy (SBRT) dose conformity for a noncoplanar volumetric modulated arc therapy (VMAT) technique. Retrospectively, 288 previously treated lung SBRT cases were replanned using a VMAT technique of 2 ipsilateral 180° arcs separated by 30° couch angles. Two objectives were used for optimization: a lower objective to achieve planning target volume (PTV) coverage and a custom normal tissue objective to steepen the dose gradient. The dose was calculated using Acuros. PTV coverage was 95%. Doses to the spinal cord, chest wall, esophagus, great vessels, heart, lungs, and trachea were evaluated. Conformity index (CI, isodose volume/PTV) values were recorded at the 10% to 100% isodose levels. CI50% results were benchmarked against the corresponding clinical plans and evaluated using the Wilcoxon signed-rank test. Linear regression was performed to characterize the relationship between dose conformity and the following PTV features: Hounsfield Units, volume, surface area, surface-to-volume ratio, and compactness. Compared with the clinical plans, the 2-objective VMAT plans demonstrated comparable or superior sparing of organs at risk with improvements in CI at the 10% to 100% isodose levels, all of which were statistically significant (P < .001). The average reductions in CI30% and CI50% were 3.5 and 0.63, respectively. Compared with the clinical plans, cases exceeding Radiation Therapy Oncology Group CI50% limits were reduced from n = 10 to 0 unacceptable and n = 78 to 20 acceptable variations. At CI30% to CI60%, regression showed that PTV Hounsfield Units and surface-to-volume ratio were significant (P < .001) predictors of dose conformity. An easily implementable VMAT technique achieved improved conformity across a broad range of lung SBRT cases and is now the standard at our institution. Further, dose conformity was characterized at different isodose levels with consideration of PTV features. Results from this study supplement historic clinical trial guidelines by providing more comprehensive and patient-specific goals for lung SBRT dose conformity.

326 Background: Fluciclovine PET-guided prostate cancer (PCa) radiotherapy (XRT) improves failure-free survival (FFS) over conventional imaging (CI) alone in post-prostatectomy (RRP) recurrence (EMPIRE-1, PMID: 33971152). In this randomized trial we explored dose-escalation (DE) to sites of PET uptake (not done in EMPIRE-1) using either fluciclovine or 68 GaPSMA PET/CT-guided XRT and compared cancer control to the fluciclovine PET arm of EMPIRE-1 2Y failure free survival (FFS) of 79.6%. Methods: From 2019-2023, 140 pts w/ PCa with detectable PSA post-RRP & negative CI were stratified by: (a) PSA (<1.0 v ≥ 1.0 ng/mL), (b) adverse path [+ECE, +SV, +margin, +node] (0 v any) & (c) ADT (Y v N) & randomized to XRT directed by fluciclovine (Arm 1) v 68 GaPSMA (Arm 2). In both Arms, XRT decisions were PET determined: (A) extrapelvic (EP) uptake (no XRT); (B) pelvic uptake (XRT to pelvis + prostate bed [PB]); (C) PB only uptake (XRT to PB); & (D) no uptake (XRT to PB). Pelvic dose: 45.0-50.4/1.8 Gy (with optional DE {to PET uptake} up to 56 Gy); PB dose: 64.8-70.2 Gy (with optional DE up to 76 Gy). Failure was defined as in EMPIRE-1. Primary endpoint, declared a priori, was 2Y FFS comparing entire cohort [Arms (1+2)] to the 79.6% 2Y FFS of the fluciclovine PET arm of EMPIRE-1 using Z-test. KM curves for Arms 1 & 2 were compared using log-rank test. Univariate (UV) & multivariable (MV) analyses were performed by Cox proportional hazards model on demographic, disease, & treatment factors. Provider-reported [acute & late, GI & GU] toxicities were compared using χ 2 test. Results: 140 pts were enrolled (Arm 1: 70; Arm 2: 70). Arms were balanced on age, race, PSA, GG, ECE, SV, margin, node, & ADT use. 5 pts in Arm 1 and 1 pt in Arm 2 withdrew before PET. For pts completing XRT (Arm 1: 59; Arm 2: 60), median FU was 2.00 years. For primary endpoint, 2Y FFS for Arm (1+2) 87.4 v 79.6% target from EMPIRE-1 (p=0.018). There were no significant differences in 2Y FFS between Arm 1 v Arm 2 (88.2% v 86.9%, p=0.604). PET uptake in Arms 1 v 2 were: EP: 5 v 8; pelvic+/-PB: 10 v 10; PB only: 47 v 24; none: 3 v 27. Typical PB DE (n=74) was 74 Gy & pelvis DE (n= 16) was 55 Gy. For Arm 1 v Arm 2, covariates reaching p <0.10 on UV analysis were: +SV (p=0.010), +margin (p=0.039), PB uptake (p=0.068), & PB boost (p=0.085), and on MV analyses were: +SV (p=0.004), ADT (p=0.067), +margin (p=0.069), & PB boost (p=0.096). Toxicity was similar & low in both Arms 1 & 2. Conclusions: Although fluciclovine had higher diagnostic yield in the PB & 68 GaPSMA had higher yield for EP disease, both radiotracers had similar yield in the pelvic LN, & both radiotracers had similar impact on FFS in this setting. Integrating either fluciclovine or 68 GaPSMA into post-RRP XRT planning for DE to sites of PET uptake in PB or pelvis resulted in improved FFS over a prior trial in which no DE was performed; other factors may also have contributed to this observed difference. Clinical trial information: NCT03762759 .

This study investigated a straightforward treatment planning technique for definitive stereotactic body radiation therapy (SBRT) for patients with early-stage lung cancer aimed at increasing dose to gross disease by strategically penalizing the normal tissue objective (NTO) in the EclipseTM treatment planning system. Twenty-five SBRT cases were replanned to 50 Gy in 5 fractions using static and dynamic NTO methods (50 plans total). The NTO had a start dose of 100% at the target border, end dose of 20%, fall-off rate of 0.4/mm, and a priority of 150. For the static NTO plans, a lower planning target volume (PTV) objective was placed at 52 Gy with a priority of 100. Maximum dose was not penalized. Optimization was performed without user interaction. In contrast, the planner incrementally increased the priority of the NTO on the dynamic NTO plans until 95% of the target volume was covered by the prescription dose. Further, the dynamic NTO plans used both PTV lower and upper objectives at 63-64 Gy with priorities of 50. Maximum dose was penalized to ensure that the hot spot was within ± 2% of the static NTO global maximum dose. Following optimization, all plans were normalized so that the prescription dose covered 95% of the PTV. Plans were scored based on RTOG 0813 criteria, and dose to the internal target volume (ITV) and PTV was evaluated. The Wilcoxon signed-rank test (threshold = 0.05) was used to evaluate differences between the static and dynamic NTO plans. All plans met RTOG 0813 planning guidelines. In comparison to the static NTO plans, the dynamic NTO plans exhibited statistically significant increases in PTV mean dose, ITV mean dose, and PTV-ITV mean dose. Notably, the dynamic NTO plans more effectively concentrated the high dose on gross disease at the center of the PTV. As compared to the static NTO plans, the mean dose was 4.6 Gy higher in the ITV while only 1.3 Gy higher in the PTV-ITV rind of the dynamic NTO plans. Global maximum doses were similar. There were some small yet statistically significant differences in dose conformity between plan types. Furthermore, the dynamic NTO plans demonstrated a significant reduction in total monitor units (MU). This study demonstrated an efficient optimization strategy for lung SBRT plans that concentrates the highest dose in the gross disease, which may improve local control.

This study investigated optimization settings that steepen the dose gradient as a function of target size for lung stereotactic body radiation therapy (SBRT). Sixty-eight lung SBRT patients with planning target volumes (PTVs) ranging from 2-203 cc were categorized into small (< 20 cc), medium (20-50 cc), and large (> 50 cc) groups. VMAT plans were generated using the normal tissue objective (NTO) to penalize the dose gradient at progressively steeper NTO fall-off values (0.1, 0.2, 0.3, 0.4, 0.5 mm(-1)). Dose was calculated using the AcurosXB algorithm and was normalized so the prescription dose covered 95% of the PTV. Mann-Whitney, Kruskal-Wallis and ANOVA tests were used to assess for statistical differences in the Conformity Index at the 50% isodose level (CI50%), global maximum dose (D-max), and monitor units (MU) across the various NTO settings. All plans adhered to institutional criteria and met the guidelines of the Radiation Therapy Oncology Group 0813. Steeper NTO fall-off values significantly increased Dmax and MUs across all groups ( p < 0.05). CI50% significantly differed with fall-off values in small (0.3 mm(-1)) and medium (0.2 mm(-1)) targets, indicating steeper NTO fall-off values improve CI50% for small and medium targets (p < 0.05). Large targets showed no significant CI50% difference across these fall-off values. As target size increases, the importance of fall-off values in achieving an acceptable CI50% diminishes. Smaller targets benefit from steeper fall-off values despite increased D-max and MUs. Consideration of fall-off value relative to target size is crucial to limit dose spillage outside the target. (c) 2024 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Background: Pediatric high-grade glioma (pHGG) is a highly aggressive cancer with unique biology distinct from adult high-grade glioma, limiting the effectiveness of standard treatment protocols derived from adult research. Objective: The purpose of this report is to present preliminary results from an ongoing pilot study integrating spectroscopic magnetic resonance imaging (sMRI) to guide proton beam therapy and longitudinal imaging analysis in pediatric patients with high-grade glioma (pHGG). Methods: Thirteen pediatric patients under 21 years old with supratentorial WHO grade III-IV glioma underwent baseline and serial whole-brain spectroscopic MRI alongside standard structural MRIs. Radiation targets were defined using T1-weighted contrast enhanced, T2-FLAIR, and Cho/NAA ≥ 2X maps. Longitudinal analyses included voxel-level metabolic change maps and spatial overlap metrics comparing pre-proton therapy and post-. Results: Six patients had sufficient longitudinal data; five received sMRI-guided PBT. Significant positive correlation (R2 = 0.89, p < 0.0001) was observed between T2-FLAIR and Cho/NAA ≥ 2X volumes. Voxel-level difference maps of Cho/NAA and Choline revealed dynamic metabolic changes across follow-up scans. Analyzing Cho/NAA and Cho changes over time allowed differentiation between true progression and pseudoprogression, which conventional MRI alone struggles to achieve. Conclusions: Longitudinal sMRI enhanced metabolic tracking in pHGG, detects early tumor changes, and refines RT targeting beyond structural imaging. This first in-kind study highlights the potential of sMRI biomarkers in tracking treatment effects and emphasizes the complementary roles of metabolic and radiographic metrics in evaluating therapy response in pHGG.

BACKGROUND AND OBJECTIVE:In EMPIRE-1, [18F]-fluciclovine positron emission tomography (PET) imaging to guide salvage radiotherapy (RT) for prostate cancer recurrence after prostatectomy resulted in an improvement in event-free survival (EFS) over conventional imaging alone. The aim of EMPIRE-2 was to explore the impact of RT dose escalation to sites of uptake on PET in comparison to EMPIRE-1. METHODS:EMPIRE-2 was a randomized trial of [18F]-fluciclovine versus [68Ga]-PSMA-11 in a cohort of men with biochemical progression after prostatectomy and negative conventional imaging findings. After stratification, patients were randomized to RT guided by [18F]-fluciclovine PET (arm 1) or [68Ga]-PSMA-11 PET (arm 2). PET findings were used for treatment decisions and for RT dose escalation (≤76.0 Gy to the prostate bed and ≤56.0 Gy to the pelvis). The primary endpoint was 2-yr EFS in comparison to the [18F]-fluciclovine RT arm in EMPIRE-1. The secondary endpoint was a planned EFS comparison for [18F]-fluciclovine versus [68Ga]-PSMA-11 in EMPIRE-2. KEY FINDINGS AND LIMITATIONS:In the cohort of 140 patients, 59 randomized to arm 1 patients and 60 randomized to arm 2 completed RT. Median follow-up was 2.6 yr (interquartile range 1.8-4.0). The 2-yr EFS rates were 87% for the overall EMPIRE-2 cohort versus 80% for the EMPIRE-1 comparison cohort (difference 7.7%, 95% confidence interval [CI] 4.7-12%; p = 0.01). After propensity score weighting, the corresponding 2-yr EFS rates were 84% versus 73% (difference 11%, 95% CI 3.6-24%; p = 0.01). The 2-yr EFS rates in the EMPIRE-2 study arms were 87% for [18F]-fluciclovine versus 88% for [68Ga]-PSMA-11 (difference 0.7%, 95% CI 0.3-1.3%; p > 0.9). CONCLUSIONS AND CLINICAL IMPLICATIONS:Use of either [18F]-fluciclovine or [68Ga]-PSMA-11 imaging to guide RT dose escalation to sites of PET uptake in the prostate bed and/or pelvis was associated with an improvement in EFS in comparison to a prior trial without dose escalation.

Background: Recent patient studies have linked higher immune cell doses with worse quality of life and survival. For thoracic radiotherapy, heart dose is a major contributor to the effective dose to immune cells (EDIC). Purpose: This study investigates heart and immune cell doses for plans optimized using a cardiac-sparing knowledge-based planning (KBP) model and the impact of carefully crafted beam geometry. Methods: Sixteen stage III NSCLC patients previously treated to 60 Gy in 30 fractions using coplanar VMAT arcs were replanned using a cardiac-sparing KBP model with either the clinical field arrangement or noncoplanar oblique arcs that prioritize heart sparing. The cardiac-sparing KBP model consisted of fifteen substructures, all of which were used during optimization. All plans were normalized to 95% PTV coverage at 60 Gy. Statistical significance was assessed for EDIC (Jin Model), along with mean doses to the heart, lungs, body, and both the mean dose and D0.03 cc values for cardiac substructures, using the Wilcoxon signed-rank test. Results: Compared to the clinically treated plans with the same beam geometry, cardiac-sparing KBP reduced mean heart dose from 8.50 Gy to 4.09 Gy and EDIC from 4.27 Gy to 3.81 Gy (p < 0.001). For the novel arcs, the mean heart dose was reduced to 3.70 Gy, significantly lower than KBP with clinical beam geometry (p = 0.001). EDIC, however, was equivalent. No statistically meaningful differences were observed for the remaining organs at risk, and all plans met institutional planning goals. Conclusion: Cardiac-sparing RapidPlan is a valuable tool for reducing heart dose and lowering EDIC in NSCLC patients. Additional heart sparing is possible by strategically crafting noncoplanar oblique beams to minimize heart dose.

Current diagnostic and therapeutic approaches for gliomas have limitations hindering survival outcomes. We propose spectroscopic magnetic resonance imaging as an adjunct to standard MRI to bridge these gaps. Spectroscopic MRI is a volumetric MRI technique capable of identifying tumor infiltration based on its elevated choline (Cho) and decreased N-acetylaspartate (NAA). We present the clinical translatability of spectroscopic imaging with a Cho/NAA ≥ 5x threshold for delineating a biopsy target in a patient diagnosed with non-enhancing glioma. Then, we describe the relationship between the undertreated tumor detected with metabolite imaging and overall survival (OS) from a pilot study of newly diagnosed GBM patients treated with belinostat and chemoradiation. Each cohort (control and belinostat) were split into subgroups using the median difference between pre-radiotherapy Cho/NAA ≥ 2x and the treated T1-weighted contrast-enhanced (T1w-CE) volume. We used the Kaplan–Meier estimator to calculate median OS for each subgroup. The median OS was 14.4 months when the difference between Cho/NAA ≥ 2x and T1w-CE volumes was higher than the median compared with 34.3 months when this difference was lower than the median. The T1w-CE volumes were similar in both subgroups. We find that patients who had lower volumes of undertreated tumors detected via spectroscopy had better survival outcomes.

Purpose/Objective(s) There are few patient reported outcomes (PROs) data following brain reRT. We hypothesized that the short-term toxicity profile of proton-based brain reRT is modest. Materials/Methods We examined patients with prior brain-directed RT who received overlapping brain reRT with pencil beam proton therapy and completed pretreatment and 3-month post-radiation (postRT) PROs as part of a prospective outcomes registry which included PROMIS Fatigue (PF, a 4-point change is the median estimate of a clinically meaningful difference) and Cognitive (PC) instruments and the MD Anderson Symptom Inventory for Brain Tumors (MDASI-BT). Changes in PRO scores over time were analyzed with a Wilcoxon signed rank test for paired data and Mann-Whitney U test to assess correlations with clinical variables. Results 26 patients were evaluable with a median age of 54 years (20-75). The most common indications for reRT were progressive or recurrent meningioma (n = 10) or glioma (n = 7). None received craniospinal re-RT; 7 received concurrent systemic therapy. The prior overlapping RT was fractionated in 19 and SRS in 9, with 4 having multiple prior courses. For reRT, 19 received conventional fractionation (range = 45 – 60 Gy), 6 moderate hypofractionation (range = 35 – 50 Gy), and 1 proton-based SBRT (30 Gy, 5 fxs). The median nominal cumulative dose was 102 Gy. The median interval from prior RT was 40 months (9-240). There was no statistically significant difference between baseline and 3-month postRT scores for the PF, PC, or mean MDASI-BT Symptom or Interference scores. 11 patients had a 4-point worsening in PF scores at 3 months post-RT: 7 newly entering the moderate severity range and none newly entering severe. For PC, no patient newly reported moderate or worse cognitive impairment at 3 months postRT. Comparing the (baseline, 3-month postRT) median MDASI-BT scores, there was a statistically significant higher (worse) median score for drowsiness (3, 4.5), dry mouth (0, 2), difficulty understanding (1, 2) and appearance (0, 0.5) though the median scores remained low, below a moderate level of severity on the 0-10 MDASI-BT scale. At baseline and 3 months postRT, those with an ECOG performance status (PS) of 1+ (n = 13) reported a statistically significant worse PF and MDASI-BT Interference scores compared to those with a baseline ECOG PS = 0 (n = 12). At 3 months postRT, the four patients requiring steroids reported statistically worse MDASI-BT Interference scores, particularly in relationships and enjoyment of life. Conclusion CNS-directed proton reRT was associated with modest changes in patient reported outcomes with ∼27% reporting a new moderate level of fatigue at 3 months postRT. Those with a worse baseline ECOG PS and those requiring steroids reported a greater detriment on quality of life. These data are helpful in counseling on short term side effects and shared decision making when considering CNS proton reRT.

Purpose To investigate bolus design and VMAT optimization settings for total scalp irradiation.Methods Three silicone bolus designs (flat, hat, and custom) from .decimal were evaluated for adherence to five anthropomorphic head phantoms. Flat bolus was cut from a silicone sheet. Generic hat bolus resembles an elongated swim cap while custom bolus is manufactured by injecting silicone into a 3D printed mold. Bolus placement time was recorded. Air gaps between bolus and scalp were quantified on CT images. The dosimetric effect of air gaps on target coverage was evaluated in a treatment planning study where the scalp was planned to 60 Gy in 30 fractions. A noncoplanar VMAT technique based on gEUD penalties was investigated that explored the full range of gEUD alpha values to determine which settings achieve sufficient target coverage while minimizing brain dose. ANOVA and the t-test were used to evaluate statistically significant differences (threshold = 0.05).Results The flat bolus took 32 +/- 5.9 min to construct and place, which was significantly longer (p < 0.001) compared with 0.67 +/- 0.2 min for the generic hat bolus or 0.53 +/- 0.10 min for the custom bolus. The air gap volumes were 38 +/- 9.3 cc, 32 +/- 14 cc, and 17 +/- 7.0 cc for the flat, hat, and custom boluses, respectively. While the air gap differences between the flat and custom boluses were significant (p = 0.011), there were no significant dosimetric differences in PTV coverage at V57Gy or V60Gy. In the VMAT optimization study, a gEUD alpha of 2 was found to minimize the mean brain dose.Conclusions Two challenging aspects of total scalp irradiation were investigated: bolus design and plan optimization. Results from this study show opportunities to shorten bolus fabrication time during simulation and create high quality treatment plans using a straightforward VMAT template with simple optimization settings.

Purpose: Peer review in the form of chart rounds is a critical component of quality assurance and safety in radiation therapy treatments. Radiation therapy departments have undergone significant changes that impose challenges to meaningful review, including institutional growth and increasing use of virtual environment. We discuss the implementation of a novel chart rounds (NCR) format and application adapted to modern peer review needs at a single high-volume multisite National Cancer Institute designated cancer Methods and Materials: A working group was created to improve upon the prior institutional chart rounds format (standard chart rounds or SCR). Using a novel in-house application and format redesign, an NCR was created and implemented to accomplish stated goals. Data regarding the SCR and NCR system were then extracted for review. Results: SCR consisted of 2- 90-minute weekly sessions held to review plans across all disease sites, review of 49 plans per hour on average. NCR uses 1-hour long sessions divided by disease site, enabling additional time to be spent per patient (11 plans per hour on average) and more robust discussion. The NCR application is able to automate a list of plans requiring peer review from the institutional treatment planning system. The novel application incorporates features that enable efficient and accurate review of plans in the virtual setting across multiple sites. A systematic scoring system is integrated into the application to record feedback. Over 5 months of use of the NCR, 1160 plans have been reviewed with 143 scored as requiring minor changes, 32 requiring major changes and 307 with comments. Major changes triggered treatment replan. Feedback from scoring is incorporated into physician workflow to ensure changes are addressed. Conclusion: The presented NCR format and application enables standardized and highly reliable peer review of radiation therapy plans that is robust across a variety of complex planning scenarios and could be implemented globally. (c) 2023 The Authors. Published by Elsevier Inc. on behalf of American Society for Radiation Oncology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).