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Purpose/Objective(s) A United States (US) radiation oncology (RO) curriculum, developed by key stakeholders using best practices for curriculum inquiry, is needed to guide residency education and qualifying examinations. Competency-based training, including entrustable professional activities (EPAs), provides an outcomes-based approach to modern graduate medical education. This study developed the first list of US RO EPAs and curricular content domains (CDs) to guide resident training and assessment in the modern era. Materials/Methods The Radiation Oncology Education Collaborative Study Group (ROECSG) Core Curriculum Project Leadership Committee (LC) developed initial EPAs and CDs. Following recruitment of stakeholders, a Delphi process was used for consensus. In the first Delphi, EPAs and CDs were reviewed for inclusion/exclusion, clarity, level of training (EPAs only), and time allocation (CDs only). Participants submitted additional EPAs/CDs for consideration. Any EPA or CD one standard deviation below the median underwent LC review. All participants completing the first Delphi were invited to the second. New EPAs or EPAs undergoing major revisions were re-reviewed. Percent allocated curriculum time was finalized for CDs and for a single subdomain (SD). Results 186 participants representing diverse RO stakeholder groups volunteered to participate. 114 completed the first Delphi (61.3%): 6/9 CDs met consensus, 1 CD was removed, 2 CDs were combined (Table 1). Of 114 invited, 77 participants completed the second Delphi (67.5%). Of 55 initial EPAs, 52 final EPAs met consensus. 4 SDs of a single CD (Applied Sciences) were reviewed and met consensus. Consensus on percent time allocated per CD and SD was reached (Table 1). Conclusion Deliberative curriculum inquiry was successfully used to develop a consensus on US RO CDs/SDs and EPAs. These data can guide educational time in training programs and help inform weighting for qualifying examinations. CDs are not exclusive; educators must ensure all CDs are considered when delivering curriculum content, regardless of the primary CD. RO-specific EPAs can guide clinical training and resident assessment. The Delphi should be used to reach consensus recommendations for SD content breakdown. Given the evolving nature of RO and the need for curriculum renewal, the Delphi process will be repeated on an interval basis.

Introduction Historical reservations regarding radiosurgery (SRS) for small-cell-lung-cancer (SCLC) brain metastases (BrM) include concerns for short-interval/diffuse CNS-progression, poor prognoses, and increased neurological mortality specific to SCLC histology. We compared SRS outcomes for SCLC and non-small-cell-lung-cancer (NSCLC) where SRS is well established. Methods Multicenter first-line SRS outcomes for SCLC and NSCLC from 2000-2022 were retrospectively collected (N=892-SCLC/N=4,785-NSCLC). Data from the prospective JLGK0901 SRS trial were analyzed as a comparison cohort (N=98-SCLC/N=794-NSCLC). OS and CNS-progression were analyzed using Cox-Proportional-Hazard and Fine-Gray models, respectively, with multivariable (MV) adjustment (including age/sex/performance-status/year/extracranial disease/BrM-number/BrM-volume). Mutation-stratified analyses were performed in propensity score-matched (PSM) retrospective cohorts of EGFR/ALK-positive-NSCLC, mutation-negative-NSCLC, and SCLC. Results OS was superior with NSCLC over SCLC in the retrospective dataset (median-OS, 10.5 vs 8.6 months, MV-p Conclusion After SRS, SCLC was associated with shorter OS compared to NSCLC. CNS progression occurred earlier in SCLC overall but was similar in patients matched on baseline characteristics. Neurological mortality, lesions at CNS-progression, and leptomeningeal-progression were comparable. These findings may better inform clinical decision-making for SCLC patients.

PURPOSE: Radiation pneumonitis remains a major limitation in the radiation therapy treatment of patients with lung cancer. Functional avoidance radiation therapy uses functional imaging to reduce pulmonary toxic effects by designing radiation therapy plans that reduce doses to functional regions of the lung. Lung functional imaging has been developed that uses 4-dimensional computed tomography (4DCT) imaging to calculate 4DCT-based lung ventilation (4DCT-ventilation). A phase 2 multicenter study was initiated to evaluate 4DCT-ventilation functional avoidance radiation therapy. The study hypothesis was that functional avoidance radiation therapy could reduce the rate of grade ≥2 radiation pneumonitis to 12% compared with a 25% historical rate, with the trial being positive if ≤16.4% of patients experienced grade ≥2 pneumonitis. METHODS AND MATERIALS: Lung cancer patients receiving curative-intent radiation therapy (prescription doses of 45–75 Gy) and chemotherapy were accrued. Patient 4DCT scans were used to generate 4DCT-ventilation images. The 4DCT-ventilation images were used to generate functional avoidance plans that reduced doses to functional portions of the lung while delivering the prescribed tumor dose. Pneumonitis was evaluated by a clinician at 3, 6, and 12 months after radiation therapy. RESULTS: Sixty-seven evaluable patients were accrued between April 2015 and December 2019. The median prescription dose was 60 Gy (range, 45–66 Gy) delivered in 30 fractions (range, 15–33 fractions). The average reduction in the functional volume of lung receiving ≥20 Gy with functional avoidance was 3.5% (range, 0%–12.8%). The median follow-up was 312 days. The rate of grade ≥2 radiation pneumonitis was 10 of 67 patients (14.9%; 95% upper CI, 24.0%), meeting the phase 2 criteria. CONCLUSIONS: 4DCT-ventilation offers an imaging modality that is convenient and provides functional imaging without an extra procedure necessary. This first report of a multicenter study of 4DCT-ventilation functional avoidance radiation therapy provided data showing that the trial met phase 2 criteria and that evaluation in a phase 3 study is warranted.

Purpose:Patients with human EGFR2-positive (HER2+) breast cancer have a high incidence of brain metastases, and trastuzumab emtansine (T-DM1) is often employed. Stereotactic radiosurgery (SRS) is frequently utilized, and case series report increased toxicity with combination SRS and T-DM1. We provide an update of our experience of T-DM1 and SRS evaluating risk of clinically significant radionecrosis (CSRN) and propose a mechanism for this toxicity.Experimental Design:Patients with breast cancer who were ≤45 years regardless of HER2 status or had HER2+ disease regardless of age and underwent SRS for brain metastases were included. Rates of CSRN, SRS data, and details of T-DM1 administration were recorded. Proliferation and astrocytic swelling studies were performed to elucidate mechanisms of toxicity.Results:A total of 45 patients were identified; 66.7% were HER2+, and 60.0% were ≤ 45 years old. Of the entire cohort, 10 patients (22.2%) developed CSRN, 9 of whom received T-DM1. CSRN was observed in 39.1% of patients who received T-DM1 versus 4.5% of patients who did not. Receipt of T-DM1 was associated with a 13.5-fold (P = 0.02) increase in CSRN. Mechanistically, T-DM1 targeted reactive astrocytes and increased radiation-induced cytotoxicity and astrocytic swelling via upregulation of Aquaporin-4 (Aqp4).Conclusions:The strong correlation between development of CSRN after SRS and T-DM1 warrants prospective studies controlling for variations in timing of T-DM1 and radiation dosing to further stratify risk of CSRN and mitigate toxicity. Until such studies are completed, we advise caution in the combination of SRS and T-DM1.

Chemotherapy effects on astrocytes

Clinical Practice Points • Selpercatinib and pralsetinib both have high extracranial efficacy in RET fusion-positive non-small cell lung cancer (NSCLC). • We present a case of a patient with RET fusion-positive NSCLC who had a durable extracranial response to pralsetinib, but had leptomeningeal progression. She subsequently had both a clinical and radiographic CNS response to selpercatinib. • Future studies should compare the intracranial efficacy with these 2 RET inhibitors, with implications on choice and sequence of their use.

In its current form, the Radiation Oncology Model (RO Model) prioritizes payment cuts over true value-based payment transformation. With significant modifications to the payment methodology, the reporting requirements, and recognition of the unique challenges faced by disadvantaged populations, the RO Model can protect patient access to care, preserve the physician-patient decision-making process, and ensure the delivery of high-quality, efficient radiation therapy treatment. The American Society for Radiation Oncology has spent several years advocating for a meaningful alternative payment model for radiation oncology and continues to push The Center for Medicare and Medicaid Innovation for changes to the RO Model that will recognize these key outcomes.

Purpose Twitter is an increasingly popular social media platform within the health care community. The objective of this analysis is to characterize the profile of radiation oncology–related tweets and Twitter users over the past 6 years. Methods and Materials Using the web-based social media analytics platform Symplur Signals, we filtered tweets containing at least 1 of the following hashtags or key words: #radonc, #radiationoncology, "rad onc," or "radiation oncology." We evaluated radiation oncology–related Twitter activity between October 2014 and March 2020 for tweet frequency, tweet content, and individuals or groups posting tweets. We identified the most influential Twitter users contributing to radiation oncology–related tweets. Results From 2014 to 2020, the quarterly volume of radiation oncology–related tweets increased from 5027 to 29,763. Physicians contributed the largest growth in tweet volume. Academic radiation oncologists comprise 60% of the most influential Twitter accounts responsible for radiation oncology–related content. The number of radiation-oncology resident physicians on Twitter increased from 25 to 328 over the past 6 years, and 20% of radiation-oncology residency programs have a Twitter account. Seventy-one percent of radiation oncology–related tweets generated direct communication via mentions, and 59% of tweets contain links to external sources, including scientific articles. Conclusions The number of physicians contributing radiation oncology–related Twitter content has increased significantly in recent years. Academic radiation oncologists are the primary influencers of radiation oncology–related Twitter activity. Twitter is used by radiation oncologists to both professionally network and discuss findings related to the field. There remains the opportunity for radiation oncologists to broaden their audience on Twitter to encompass a more diverse community, including patients.

Stereotactic body radiation therapy (SBRT) has emerged as an effective, noninvasive treatment option for primary liver cancer and metastatic disease occurring in the liver. Although SBRT can be highly effective for establishing local control in hepatic malignancies, a tradeoff exists between tumor control and normal tissue complications. The objective of the present study was to review the normal tissue dose-volume effects for SBRT-induced liver and gastrointestinal toxicities and derive normal tissue complication probability models.

Purpose To identify causes of error, and present the concept of an automated technique that improves efficiency and helps to reduce transcription and manual data entry errors in the treatment planning of total body irradiation (TBI). Methods Analysis of incidents submitted to incident learning system (ILS) was performed to identify potential avenues for improvement by implementation of automation of the manual treatment planning process for total body irradiation (TBI). Following this analysis, it became obvious that while the individual components of the TBI treatment planning process were well implemented, the manual ‘bridging’ of the components (transcribing data, manual data entry etc.) were leading to high potential for error. A C#‐based plug‐in treatment planning script was developed to remove the manual parts of the treatment planning workflow that were contributing to increased risk. Results Here we present an example of the implementation of “Glue” programming, combining treatment planning C# scripts with existing spreadsheet calculation worksheets. Prior to the implementation of automation, 35 incident reports related to the TBI treatment process were submitted to the ILS over a 6‐year period, with an average of 1.4 ± 1.7 reports submitted per quarter. While no incidents reached patients, reports ranged from minor documentation issues to potential for mistreatment if not caught before delivery. Since the implementation of automated treatment planning and documentation, treatment planning time per patient, including documentation, has been reduced; from an average of 45 min pre‐automation to

Purpose Studies have noted a link between radiation dose to the heart and overall survival (OS) for patients with lung cancer treated with chemoradiation. The purpose of this study was to characterize pre- to posttreatment cardiac metabolic changes using fluorodeoxyglucose/positron emission tomography (FDG-PET) images and to evaluate whether changes in cardiac metabolism predict for OS. Methods and Materials Thirty-nine patients enrolled in a functional avoidance prospective study who had undergone pre- and postchemoradiation FDG-PET imaging were evaluated. For each patient, the pretreatment and posttreatment PET/CTs were rigidly registered to the planning CT, dose, and structure set. PET-based metabolic dose-response was assessed by comparing pretreatment to posttreatment mean standardized uptake values (SUVmean) in the heart as a function of dose-bin. OS analysis was performed by comparing SUVmean changes for patients who were alive or had died at last follow-up and by using a multivariate model to assess whether pre- to posttreatment SUVmean changes were a predictor of OS. Results The dose-response curve revealed increasing changes in SUV as a function of cardiac dose with an average SUVmean increase of 1.7% per 10 Gy. Patients were followed for a median of 437 days (range, 201-1131 days). SUVmean change was significantly predictive of OS on multivariate analysis with a hazard ratio of 0.541 (95% confidence intervals, 0.312-0.937). Patients alive at follow-up had an average increase of 17.2% in cardiac SUVmean while patients that died had an average decrease in SUVmean decrease of 13.5% (P = .048). Conclusions Our data demonstrated that posttreatment SUV changes in the heart were significant indicators of dose-response and predictors of OS. The present work is hypothesis generating and must be validated in an independent cohort. If validated, our data show the potential for cardiac metabolic changes to be an early predictor for clinical outcomes.

OBJECTIVEStereotactic radiosurgery (SRS) is increasingly used for the treatment of brain metastasis. To date, most studies have focused on survival, radiological response, or surrogate quality endpoints such as Karnofsky Performance Scale status or neurocognitive indices. The current study prospectively evaluated pre-procedural factors impacting quality of life in brain metastasis patients undergoing SRS.METHODSUsing a national, cloud-based platform, patients undergoing SRS for brain metastasis were accrued to the registry. Quality of life prior to SRS was assessed using the 5-level EQ-5D (EQ5D-L) validated tool; additionally, patient and treatment attributes were collected. Patient quality of life was assessed as part of routine follow-up after SRS. Factors predicting a difference in the aggregate EQ5D-L score or the subscores were evaluated. Pre-SRS covariates impacting changes in EQ5D-L were statistically evaluated. Statistical analyses were conducted using multivariate linear regression models.RESULTSEQ5D-L results were available for 116 patients. EQ5D-L improvement (average of 0.387) was noted in patients treated with earlier SRS (p = 0.000175). Worsening overall EQ5D-L (average of 0.052 per lesion) was associated with an increased number of brain metastases at the time of initial presentation (p = 0.0399). Male sex predicted a risk of worsening (average of 0.347) of the pain and discomfort subscore at last follow-up (p = 0.004205). Baseline subscores of pain/discomfort were not correlated with pain/discomfort subscores at follow-up (p = 0.604), whereas baseline subscores of anxiety/depression were strongly positively correlated with the anxiety/depression follow-up subscores (p = 0.0039).CONCLUSIONSAfter SRS, quality of life was likely to improve in patients treated early with SRS and worsen in those with a greater number of brain metastases. Sex differences appear to exist regarding pain and discomfort worsening after SRS. Those with high levels of anxiety and depression at SRS may benefit from medical treatment as this particular quality of life factor generally remains unchanged after SRS.

Purpose The pulse line ion accelerator (PLIA) is a low-cost accelerator concept originally designed to accelerate heavy ions. Our group has been investigating the use of PLIA to accelerate light ions and believe a multi-stage PLIA could be useful for short half-life PET isotope production. The goal of this work was to develop a single prototype fast PLIA structure and demonstrate electromagnetic wave propagation using a high-voltage pulser. Materials and methods A 1.6 m fast PLIA structure (wave speed > 107 m/s) was constructed along with a high-voltage, sinusoidal pulse generator. The latter uses capacitive voltage doubling and spark gap switching. A step-up transformer couples voltage from the pulser to the PLIA coil. Voltage measurements on the coil were made in air using a high-voltage resistive probe, while capacitive probes placed along the length of the PLIA were used to measure wave propagation with the PLIA structure filled with transformer oil. Results Voltage measurements acquired on the primary and secondary coils of the transformer coupler in air demonstrated a peak-to-peak voltage step-up of 4.2 relative to the pulser DC charging voltage. The maximum voltage time-rate-of-change on the PLIA coil was 0.76 × 1013 V/s. Capacitive probe measurements indicated voltage oscillations on the PLIA coil with half-period equal to 43 ± 0.9 ns and wave speed (with oil) of 1.2 × 107 m/s. Average and peak accelerating gradients were conservatively estimated to be 0.44 and 0.60 MV/m, respectively, with a charging voltage of 55 kV. Wave propagation was demonstrated at these gradients without flashover at a vacuum pressure of 9 × 10-6 Torr. Submerging the pulser in oil would allow for charging voltages up to 150 kV and produce accelerating gradients >1.2 MV/m. Conclusions Use of a multi-stage, fast PLIA for light ion acceleration could provide a low-cost complement to cyclotrons for the production of short half-life isotopes used for PET imaging, including carbon-11, nitrogen-13, oxygen-15, and fluorine-18.

Purpose Two-dimensional antiscatter grids (2DASG) for cone beam computed tomography (CBCT) is a new area of research to reduce scatter intensity, and consequently improve CBCT image quality. One of the challenges in implementation of 2DASGs is their septa shadows that are impinged on the projections. If these artifacts are not corrected, they may lead to ring artifacts in CBCT images. In this work, we present a novel method to suppress ring artifacts in FPD-based CBCT images. Methods Briefly, our method first detects the locations of 2DASG's septa shadows in projections and then, reduces projection pixel values in septa shadows iteratively until a residual-based convergence criterion is met. To suppress the 2DASG's septa shadows, we developed a total variation minimization (TVM) formulation, referred to as adaptive-diffusive total variation minimization (adTVM), where the diffusivity regularization parameter was adaptively adjusted during each iteration based on the magnitude of the local pixel gradients. To test our method, we have acquired CBCT scans of phantoms using three 2DASG prototypes with different grid geometries. Projections were acquired with a linac mounted CBCT system, operated in offset detector geometry. These projections were then corrected in the following steps: first, projections were corrected using a gantry angle-specific gain correction map; next, projections were corrected by applying our adTVM method. CBCT images were reconstructed using FDK filtered backprojection algorithm. To evaluate adTVM's performance, pixel value statistics and contrast-to-noise ratio (CNR) were compared in CBCT images corrected with and without our adTVM method. Results Without our adTVM method, all three 2DASG prototypes introduced ring artifacts with varying intensities in CBCT images. With our method, significant reduction in ring artifacts was observed in all test cases. Standard deviation of CT numbers was reduced by 7-74% in uniform density phantom CBCT images, CNR was increased by 8-67%, and CT number accuracy of contrast objects embedded in the phantom was preserved. Conclusion We propose a new method to suppress ring artifacts caused by the 2DASG's septa shadows in CBCT images. Our initial investigations indicated that adTVM method could substantially reduce such ring artifacts while preserving CT number accuracy and maintaining good spatial resolution. Therefore, our method may potentially play an important role in enabling the implementation of 2DASGs in flat panel detector based CBCT systems.

OBJECTIVE Stereotactic radiosurgery (SRS) has been increasingly employed in recent years to treat intracranial metastatic lesions. However, there is still a need for optimization of treatment paradigms to provide better local control and prevent progressive intracranial disease. In the current study, the authors utilized a national collaborative registry to investigate the outcomes of patients with intracranial metastatic disease who underwent SRS and to determine factors associated with lesion treatment response, overall progression, and mortality. METHODS The NeuroPoint Alliance SRS registry was queried for all patients with intracranial metastatic lesions undergoing single- or multifraction SRS at participating institutions between 2016 and 2020. The main outcomes of interest included lesion response (lesion-level analysis), progression using Response Assessment for Neuro-Oncology criteria, and mortality (patient-level analysis). Kaplan-Meier analysis was used to report time to progression and overall survival, and multivariable Cox proportional hazards analysis was used to investigate factors associated with lesion response, progression, and mortality. RESULTS A total of 501 patients (1447 intracranial metastatic lesions) who underwent SRS and had available follow-up were included in the current analyses. The most common primary tumor was lung cancer (49.5%, n = 248), followed by breast (15.4%, n = 77) and melanoma (12.2%, n = 61). Most patients had a single lesion (44.9%, n = 225), 29.3% (n = 147) had 2 or 3 lesions, and 25.7% (n = 129) had > 3 lesions. The mean sum of baseline measurements of the lesions according to Response Evaluation Criteria in Solid Tumors (RECIST) was 35.54 mm (SD 25.94). At follow-up, 671 lesions (46.4%) had a complete response, 631 (43.6%) had a partial response (≥ 30% decrease in longest diameter) or were stable (< 30% decrease but < 20% increase), and 145 (10%) showed progression (> 20% increase in longest diameter). On multivariable Cox proportional hazards analysis, melanoma-associated lesions (HR 0.48, 95% CI 0.34–0.67; p < 0.001) and larger lesion size (HR 0.94, 95% CI 0.93–0.96; p < 0.001) showed lower odds of lesion regression, while a higher biologically effective dose was associated with higher odds (HR 1.001, 95% CI 1.0001–1.00023; p < 0.001). A total of 237 patients (47.3%) had overall progression (local failure or intracranial progressive disease), with a median time to progression of 10.03 months after the index SRS. Factors found to be associated with increased hazards of progression included male sex (HR 1.48, 95% CI 1.108–1.99; p = 0.008), while administration of immunotherapy (before or after SRS) was found to be associated with lower hazards of overall progression (HR 0.62, 95% CI 0.460–0.85; p = 0.003). A total of 121 patients (23.95%) died during the follow-up period, with a median survival of 19.4 months from the time of initial SRS. A higher recursive partitioning analysis score (HR 21.3485, 95% CI 1.53202–3.6285; p < 0.001) was found to be associated with higher hazards of mortality, while single-fraction treatment compared with hypofractionated treatment (HR 0.082, 95% CI 0.011–0.61; p = 0.015), administration of immunotherapy (HR 0.385, 95% CI 0.233–0.64; p < 0.001), and presence of single compared with > 3 lesions (HR 0.427, 95% CI 0.187–0.98; p = 0.044) were found to be associated with lower risk of mortality. CONCLUSIONS The comparability of results between this study and those of previously published clinical trials affirms the value of multicenter databases with real-world data collected without predetermined research purpose.

To report trends in the number and types of applicants and matched trainees to radiation oncology in comparison to other specialties participating in the National Resident Matching Program (NRMP) between 2010 and 2020.Data from the NRMP and Electronic Residency Application System (ERAS) were obtained for 18 medical specialties between 2010 and 2020. We assessed the numbers and types of applicants and matched trainees relative to available positions in the NRMP and Supplemental Offer and Acceptance Program (SOAP).In the 2020 NRMP, 122 US MD senior graduates preferentially ranked radiation oncology, a significant decrease from a median of 187 between 2010 to 2019 (interquartile range [IQR], 170-192; P.001). Across all 18 specialties, radiation oncology experienced the greatest declines in the 2020 NRMP cycle relative to 2010 to 2019, in both the number of ERAS applicants from the United States and Canada (-31%) and the percentage of positions filled by US MD or DO senior graduates (-28%). Of 189 available positions, 81% (n = 154) filled in the NRMP prior to the SOAP, of which 65% (n = 122) were "matched" by US MD senior graduates who preferentially ranked radiation oncology as their top choice of specialty, representing a significant decrease from a median of 92% between 2010 to 2019 (IQR, 88%-94%; P = .002). The percentages of radiation oncology programs and positions unfilled in the NRMP prior to the SOAP were significantly increased in 2020 compared with 2010 to 2019 (programs: 29% vs 8% [IQR, 5%-8%; P.001]; positions: 19% vs 4% [IQR, 2%-4%; P.001]). Despite99% (n = 127 of 128) of US MD or DO senior applicants preferring radiation oncology successfully matching to a radiation oncology position in the 2020 NRMP, 16 of 35 remaining unfilled positions were filled via the SOAP. Radiation oncology was the top user of the SOAP across all specialties participating in the 2020 NRMP, filling 15% of total positions versus a median of 0.9% (IQR, 0.3%-2.3%; P.001).The supply of radiation oncology residency positions now far exceeds demand by graduating US medical students. Efforts to nullify a market correction revealed by medical student behavior via continued reliance on the SOAP to fill historical levels of training positions may not be in the best of interest of trainees, individual programs, or the specialty as a whole.

Professionalism in a healthcare environment involves not only the skills for job performance but also expectations of compliance with ethical guidelines for interactions with patients, colleagues, and society at large. Special expertise can be helpful in supporting physicians whose actions negatively impact the work environment to identify underlying drivers of problematic behaviors. It has been recognized that “hidden curricula” in the educational setting can sometimes provide favorable role models but at other times enable microaggressions that can be discriminatory and lead to larger structural inequities. Physicians should be aware that they will be judged by patient and peers on the persona projected publicly on various social media platforms.

Principles of strategic planning borrowed from the literature of business administration can be applied in the field of radiation oncology at the level of the professional society, academic department, and individual career development. Successful implementation of a strategic plan within an organization calls for awareness of the culture and working environment of the organization. The development of novel technologies can occasionally disrupt the direction of an entire industry. Mentors and sponsors who advise and promote junior faculty members’ interests can be vitally important for mapping our individual academic career success.

Highlights • Recommendations for risk-mitigation pandemic scenario: • Do not to compromise the prognosis of lung cancer patients by departing from guideline-recommended radiotherapy practice. • Postponement or interruption of radiotherapy of COVID-19 positive patients is generally recommended Severe pandemic scenario characterized by reduced resources: • Factors for patient triage include potential for cure, relative benefit of radiation, life expectancy, and performance status., Background The COVID-19 pandemic has caused radiotherapy resource pressures and led to increased risks for lung cancer patients and healthcare staff. An international group of experts in lung cancer radiotherapy established this practice recommendation pertaining to whether and how to adapt radiotherapy for lung cancer in the COVID-19 pandemic. Methods For this ESTRO & ASTRO endorsed project, 32 experts in lung cancer radiotherapy contributed to a modified Delphi consensus process. We assessed potential adaptations of radiotherapy in two pandemic scenarios. The first, an early pandemic scenario of risk mitigation, is characterized by an altered risk–benefit ratio of radiotherapy for lung cancer patients due to their increased susceptibility for severe COVID-19 infection, and minimization of patient travelling and exposure of radiotherapy staff. The second, a later pandemic scenario, is characterized by reduced radiotherapy resources requiring patient triage. Six common lung cancer cases were assessed for both scenarios: peripherally located stage I NSCLC, locally advanced NSCLC, postoperative radiotherapy after resection of pN2 NSCLC, thoracic radiotherapy and prophylactic cranial irradiation for limited stage SCLC and palliative thoracic radiotherapy for stage IV NSCLC. Results In a risk-mitigation pandemic scenario, efforts should be made not to compromise the prognosis of lung cancer patients by departing from guideline-recommended radiotherapy practice. In that same scenario, postponement or interruption of radiotherapy treatment of COVID-19 positive patients is generally recommended to avoid exposure of cancer patients and staff to an increased risk of COVID-19 infection. In a severe pandemic scenario characterized by reduced resources, if patients must be triaged, important factors for triage include potential for cure, relative benefit of radiation, life expectancy, and performance status. Case-specific consensus recommendations regarding multimodality treatment strategies and fractionation of radiotherapy are provided. Conclusion This joint ESTRO-ASTRO practice recommendation established pragmatic and balanced consensus recommendations in common clinical scenarios of radiotherapy for lung cancer in order to address the challenges of the COVID-19 pandemic.

IMPORTANCE: Although stereotactic radiosurgery (SRS) is preferred for limited brain metastases from most histologies, whole-brain radiotherapy (WBRT) has remained the standard of care for patients with small cell lung cancer. Data on SRS are limited. OBJECTIVE: To characterize and compare first-line SRS outcomes (without prior WBRT or prophylactic cranial irradiation) with those of first-line WBRT. DESIGN, SETTING, AND PARTICIPANTS: FIRE-SCLC (First-line Radiosurgery for Small-Cell Lung Cancer) was a multicenter cohort study that analyzed SRS outcomes from 28 centers and a single-arm trial and compared these data with outcomes from a first-line WBRT cohort. Data were collected from October 26, 2017, to August 15, 2019, and analyzed from August 16, 2019, to November 6, 2019. INTERVENTIONS: SRS and WBRT for small cell lung cancer brain metastases. MAIN OUTCOMES AND MEASURES: Overall survival, time to central nervous system progression (TTCP), and central nervous system (CNS) progression-free survival (PFS) after SRS were evaluated and compared with WBRT outcomes, with adjustment for performance status, number of brain metastases, synchronicity, age, sex, and treatment year in multivariable and propensity score–matched analyses. RESULTS: In total, 710 patients (median [interquartile range] age, 68.5 [62-74] years; 531 men [74.8%]) who received SRS between 1994 and 2018 were analyzed. The median overall survival was 8.5 months, the median TTCP was 8.1 months, and the median CNS PFS was 5.0 months. When stratified by the number of brain metastases treated, the median overall survival was 11.0 months (95% CI, 8.9-13.4) for 1 lesion, 8.7 months (95% CI, 7.7-10.4) for 2 to 4 lesions, 8.0 months (95% CI, 6.4-9.6) for 5 to 10 lesions, and 5.5 months (95% CI, 4.3-7.6) for 11 or more lesions. Competing risk estimates were 7.0% (95% CI, 4.9%-9.2%) for local failures at 12 months and 41.6% (95% CI, 37.6%-45.7%) for distant CNS failures at 12 months. Leptomeningeal progression (46 of 425 patients [10.8%] with available data) and neurological mortality (80 of 647 patients [12.4%] with available data) were uncommon. On propensity score–matched analyses comparing SRS with WBRT, WBRT was associated with improved TTCP (hazard ratio, 0.38; 95% CI, 0.26-0.55; P

Importance Central Nervous System (CNS) metastasis from prostate cancer (PCA) is a rare event, but one with significant prognostic impact for those affected. There are limited data on its impact in contemporary cohorts treated with modern agents. Design A retrospective institutional review was performed to characterize the occurrence/outcome of PCA CNS metastasis on all cases of PCA from 2011-2017. A manual chart review was performed to confirm PCA CNS metastases in all cases identified through a diagnostic code screening of the health data. Results 6,596 cases of PCA were identified, with 29 (20 dural and 9 intraparenchymal) confirmed cases of CNS metastases from prostate cancer. The median survival from the time of diagnosis of CNS metastasis was 2.6 (95%CI: 2.04 – 10.78) months and 5.41 (95% CI: 3.03 – not reached) months for dural and parenchymal metastases respectively. Among those who developed CNS metastases, approximately 79% of patients had prior exposure to abiraterone and/or enzalutamide, of whom 50% had ≥6 months of exposure. Four of the 5841 (0.07%) patients developed CNS metastases prior to the initiation of therapy or on androgen deprivation therapy (ADT) alone. In contrast, 24 of the 279 (8.6%) patients with 2 or more lines of medical therapy developed CNS metastases. Conclusions and Relevance: Our analysis highlights the continued poor prognosis of parenchymal and dural CNS metastases from PCA. CNS metastases in prostate cancer remain a rare event with a 0.4% incidence in this series, but this incidence is considerably increased in patients who receive medical therapy beyond first line ADT.

Purpose Positron emission tomography (PET) imaging remains limited due to the cost associated with on-site production of short half-life, positron-emitting isotopes. In this work, we examine the use of a pulse line ion accelerator (PLIA) to accelerate protons for single-dose PET isotope production. Methods Time-domain electromagnetic field and particle-in-cell (PIC) simulations were performed for a 1.5-m PLIA structure modeled in CST Microwave Studio and Particle Studio software. Scaled measurements from a kV ramp-pulse generator were incorporated into the simulations to accelerate a 1 A, 50 ns proton beam injected with initial kinetic energy of 100 keV. A uniform, 3 T, solenoidal magnetic field was used to provide external beam focusing. Electromagnetic fields and particle phase space were recorded with ns resolution for subsequent analysis. Results Applying a scaled 100 kV, 20 ns ramped voltage pulse to the PLIA input resulted in a travelling electric field wave inside the structure with accelerating gradient of 2.4 MV/m. The observed wave speed was 1.2 × 107 m/s and is in good agreement with theoretical predictions. Phase space monitors showed both acceleration and bunching of the proton beam, with a maximum kinetic energy of 2.5 MeV, observed at the exit of the single PLIA stage. Evaluation of beam position monitors at different locations in the accelerator showed bunch compression and minimal beam divergence, illustrating that the 3 T field is adequate to contain the beam over the length of the PLIA structure. Conclusion Simulations performed in this work demonstrate the feasibility of using a PLIA structure to accelerate protons with MV/m level gradients. Combining several PLIA stages in series could allow for a low-cost accelerator suitable for dose-on-demand PET isotope production.

INTRODUCTION: Brain metastases are common in metastatic melanoma and radiosurgery is often utilized for local control. Immune checkpoint inhibitors (CPIs) play a central role in contemporary melanoma management; however, there is limited data exploring outcomes and potential toxicities for patients treated with CPIs and radiosurgery. METHODS: We retrospectively identified all consecutive cases of newly diagnosed melanoma brain metastases (MBM) treated with Gamma Knife radiosurgery at a single institution between 2012 and 2017, and included only patients that initiated CPIs within 8 weeks before or after radiosurgery. RESULTS: Thirty-eight patients were included with a median follow-up of 31.6 months. Two-year local control was 92%. Median time to out-of-field CNS and extra-CNS progression were 8.4 and 7.9 months, respectively. Median progression-free survival (PFS) was 3.4 months and median overall survival (OS) was not reached (NR). Twenty-five patients (66%) received anti-CTLA4 and 13 patients (34%) received anti-PD-1+/−anti-CTLA4. Compared with anti-CTLA4, patients that received anti-PD-1+/−anti-CTLA4 had significant improvements in time to out-of-field CNS progression (p = 0.049), extra- CNS progression (p = 0.015), and PFS (p = 0.043), with median time to out-of-field CNS progression of NR vs. 3.1 months, median time to extra-CNS progression of NR vs. 4.4 months, and median PFS of 20.3 vs. 2.4 months. Six patients (16%) developed grade ≥ 2 CNS toxicities (grade 2: 3, grade 3: 3, grade 4/5: 0). CONCLUSIONS: Excellent outcomes were observed in patients that initiated CPIs within 8 weeks of undergoing radiosurgery for newly diagnosed MBM. There appears to be an advantage to anti-PD-1 or combination therapy compared to anti-CTLA4.

Purpose/Objective(s) Cancer patients often struggle to understand their own disease, symptoms, therapy and treatment-related toxicities with current educational methods. Virtual reality (VR) has the potential to intuitively convey abstract, complex information. Patients’ review and interaction of their own imaging in 3D may improve comprehension. This study aimed to assess the impact of using VR with cancer patients and their caregivers. Materials/Methods In a single arm prospectively accrued mixed-method study during clinical visits in radiation oncology, 38 cancer patients and caregivers were shown their own 2D planer medical imaging on a computer screen followed by a 3D VR volumetric review of diagnostic imaging and radiation targets. Participants completed pre- and post-VR Likert scale questionnaires and interviews. Survey analysis utilized Wilcoxon signed-rank test. Interview data was analyzed qualitatively. Results Patient ages ranged from 11-95 years old with a median of 5 months from diagnosis to VR. Participants typically noted poor comprehension using standard educational tools in clinical visits. 2D imaging review was reported as challenging to interpret, confusing and nonintuitive. Quantitatively, patient and caregiver understanding of their own disease/tumor improved significantly from pre-VR (mean 5.6) to post-VR (mean 9.2; P Conclusion Current educational strategies for cancer patients need improvement. In this prospective study, 3D VR imaging review was shown to be more effective in conveying and contextualizing complex information regarding tumor anatomical spatial relationships by substantially improving understanding over currently utilized methods. VR was patients’ most preferred and top-rated educational tool. These findings warrant evaluation of VR as a next generation educational tool in cancer patient consultations.

PURPOSE Scattered radiation remains to be a major cause of image quality degradation in Flat Panel Detector (FPD)-based Cone-beam computed tomography (CBCT). We have been investigating a novel two-dimensional antiscatter grid (2D-ASG) concept to reduce scatter intensity, and hence improve CBCT image quality. We present the first CBCT imaging experiments performed with the 2D-ASG prototype, and demonstrate its efficacy in improving CBCT image quality. METHODS A 2D-ASG prototype with septa focused to x-ray source was additively manufactured from tungsten and mounted on a Varian TrueBeam CBCT system. CBCT projections of phantoms were acquired with an offset detector geometry using TrueBeam's "developer" mode. To minimize the effect of gantry flex, projections were gain corrected on angle-specific bases. CBCT images were reconstructed using a filtered backprojection algorithm and image quality improvement was quantified by measuring contrast-to-noise ratio (CNR) and CT number accuracy in images acquired with no antiscatter grid (NO-ASG), conventional one dimensional antiscatter grid (1D-ASG), and the 2D-ASG prototype. RESULTS A significant improvement in contrast resolution was achieved using our 2D-ASG prototype compared to results of 1D-ASG and NO-ASG acquisitions. Compared to NO-ASG and 1D-ASG experiments, the CNR of material inserts improved by as much as 86% and 54% respectively. Using 2D-ASG, CT number underestimation in water equivalent material section of the phantom was reduced by up to 325 HU when compared to NO-ASG and up to 179 HU when compared to 1D-ASG. CONCLUSION We successfully performed the first CBCT imaging experiments with a 2D-ASG prototype. 2D-ASG provided significantly higher CT number accuracy, higher CNR, and diminished scatter-induced image artifacts in qualitative evaluations. We strongly believe that utilization of a 2D-ASG may potentially lead to better soft tissue visualization in CBCT and may enable novel clinical applications that require high CT number accuracy.

Objective Stereotactic radiosurgery (SRS) represents an expanding approach for neurosurgeons and radiation oncologists. We evaluate educational gaps of senior residents drawn from each specialty as part of a focused SRS course. We also evaluate the strengths and limitations of SRS training in current residency programs of the course residents and faculty. Methods The American Association of Neurological Surgeons and American Society of Radiation Oncology jointly held a senior resident course in SRS. Residents were nominated by program directors from across the United States. Thirty residents were chosen to participate in the course. The residents were surveyed before and after the course. Faculty (n = 14) were also surveyed to ascertain their perspectives on current training in SRS. Results Most (96.7%) of the residents planned to perform SRS when finished, and 94% anticipated SRS indications to expand. Regarding SRS technique, 47% reported average/above average understanding of intracranial SRS; only 17% expressed similar understanding of spinal SRS. Before the course, 76.6% noted below average/average ability to recognize and manage SRS complications. Twenty-three percent of the faculty indicated that graduating residents from their programs were unprepared to perform radiosurgery. Residents' self-assessed understanding of brain SRS indication (P = 0.000693), SRS techniques (P = 0.000021), spinal SRS indications (P = 0.000050), spinal SRS techniques (P = 0.000019), and complication recognition and management (P = 0.00033) significantly improved following the course. Conclusions Knowledge and training gaps in SRS appear evident to the senior residents and faculty of both specialties. We believe that other educational opportunities for SRS experience are necessary to optimize clinical competency, as well as meet future clinical staffing needs for this expanding, multidisciplinary approach. Further evaluation of gaps in SRS is necessary through a larger, nationwide survey of U.S. neurosurgeons, program directors, and residents.

Prophylactic cranial irradiation (PCI) for SCLC offers a consistent reduction in the incidence of brain metastases at the cost of measurable toxicity to neurocognitive function and quality of life, in the setting of characteristic pathologic changes to the brain. The sequelae of PCI have historically been justified by the perception of an overall survival advantage specific to SCLC. This rationale has now been challenged by a randomized trial in extensive-stage SCLC demonstrating equivalent progression-free survival and a trend toward improved overall survival with PCI omission in the context of modern magnetic resonance imaging (MRI) staging and surveillance. In this article, we critically examine the randomized trials of PCI in extensive-stage SCLC and discuss their implications on the historical data supporting PCI for limited-stage SCLC from the pre-MRI era. Further, we review the toxicity of moderate doses of radiation to the entire brain that underlie the growing interest in active MRI surveillance and PCI omission. Finally, the evidence supporting prospective investigation of radiosurgery for limited brain metastases in SCLC is reviewed. Overall, our aim is to provide an evidence-based assessment of the debate over PCI versus active MRI surveillance and to highlight the need for contemporary trials evaluating optimal central nervous system management in SCLC.

To analyze the national trends of patients treated radiotherapy for brain metastases from non-small cell lung cancer (NSCLC) that were found at diagnosis.The National Cancer Database was queried for patients with NSCLC diagnosed from 2004 to 2013 that received brain irradiation for metastases and patients grouped into having had received fractionated brain radiotherapy (5-15 fractions with or without radiosurgery) or intracranial radiosurgery alone (1-5 fractions). Univariable and multivariable (MVA) analyses were performed to investigate factors associated with the receipt of SRS alone, and temporal/regional trends.47,746 patients met inclusion criteria, of which 42,148 received fractionated brain irradiation (88%) and 5,598 received radiosurgery (12%). 345 patients received fractioned brain irradiation with a radiosurgical boost (0.8%). The utilization of radiosurgery-alone increased over time owing to increases in each radiosurgery modality. On MVA, several factors were associated with increased odds of receiving intracranial radiosurgery-alone over fractionated brain radiotherapy including more recent year of diagnosis, increased median income, eastern U.S. regions, further distance to the hospital, and the receipt of chemotherapy (each p0.001). Patients of Asian descent were less likely to receive radiosurgery alone (p=0.044).In the management of brain metastases from NSCLC, overall utilization of an intracranial radiosurgery alone treatment strategy has increased over the past decade. Despite this, there appear to be significant geographic variations and disparities remain based on patient income level and race. Further study is needed to define the reasons for these disparities and appropriate actions to mitigate them.

Objective To compare alternative strategies for specifying cancer-free control cohorts for estimating cancer-attributable costs of care. Data Source, Study Design, Data Extraction Secondary data analysis of Surveillance, Epidemiology, and End Results data linked to Medicare claims among patients diagnosed with colorectal, lung, breast, and prostate cancers, 2007–2011. We estimated cancer-attributable costs using three alternative reference cohorts: (1) noncancer Medicare patients individually matched by demographic characteristics, (2) noncancer patients individually matched on demographic factors and comorbidity score, (3) cancer patients as their own control, using prediagnosis costs. Principal Findings Among 44,266 colorectal, 61,584 lung, 55,921 breast, and 67,733 prostate patients, mean total Medicare spending in the first year of diagnosis was $59,496, $54,261, $31,895, and $26,305, respectively. Estimates of cancer-attributable costs ranged from 79 percent to 82 percent of spending for colorectal, 76 percent–79 percent for lung, 65 percent–74 percent for breast, and 60 percent–75 percent for prostate cancers, depending on the reference cohort used. For all cancers, estimates were higher when patients were used as their own control, compared to demographic and comorbidity-matched controls. Conclusions Choice of reference group can have a substantial impact on proportion of total costs attributed to cancer and should be clearly defined in analyses of the costs of cancer care.

Background Gold nanoparticles treated with near infrared (NIR) light can be heated preferentially, allowing for thermal ablation of targeted cells. The use of novel intravesical nanoparticle-directed therapy in conjunction with laser irradiation via a fiber optic cystoscope, represents a potential ablative treatment approach in patients with superficial bladder cancer. Objective To examine the thermal ablative effect of epidermal growth factor receptor (EGFR)-directed gold nanorods irradiated with NIR light in an orthotopic urinary bladder cancer model. Methods Gold nanorods linked to an anti-EGFR antibody (Conjugated gold NanoRods - CNR) were instilled into the bladder cavity of an orthotopic murine xenograft model with T24 bladder cancer cells expressing luciferase. NIR light was externally administered via an 808 nm diode laser. This treatment was repeated weekly for 4 weeks. The anti-cancer effect was monitored by an in vivo imaging system in a non-invasive manner, which was the primary outcome of our study. Results The optimal approach for an individual treatment was 2.1 W/cm2 laser power for 30 seconds. Using this in vivo model, NIR light combined with CNR demonstrated a statistically significant reduction in tumor-associated bioluminescent activity (n = 16) compared to mice treated with laser alone (n = 14) at the end of the study (p = 0.035). Furthermore, the CNR+NIR light treatment significantly abrogated bioluminescence signals over a 6-week observation period, compared to pre-treatment levels (p = 0.045). Conclusions Photothermal tumor ablation with EGFR-directed gold nanorods and NIR light proved effective and well tolerated in a murine in vivo model of urinary bladder cancer.

Preclinical and clinical research over the past several decades suggests that hypofractionated (HFxn) radiation therapy schedules produce similar treatment outcomes compared with conventionally fractionated (CFxn) radiation therapy for definitive treatment of localized prostate cancer (PCa). We sought to evaluate national trends and identify factors associated with HFxn utilization using the US National Cancer Database.We queried the National Cancer Database for men diagnosed with localized (N0,M0) PCa from 2004 through 2013 treated with external beam radiation therapy. Patients were grouped by dose per fraction (DpF) in Gray: CFxn was defined as DpF ≤2.0, moderate HFxn as DpF2.0 but5.0, and extreme HFxn as DpF ≥5.0. Men receiving DpF1.5 or15.0 were excluded, as were those receiving25 or90 Gy total dose. Multiple logistic regression was performed to identify demographic, clinical, and treatment factor associations.A total of 132,403 men were identified, with 120,055 receiving CFxn, 7264 moderate HFxn, and 5084 extreme HFxn. Although CFxn was by far the most common approach over the analysis period, HFxn use increased from 6.2% in 2004 to 14.2% in 2013 (P.01). Extreme HFxn use increased the most (from 0.3% to 8.5%), whereas moderate HFxn utilization was unchanged (from 5.9% to 5.7%). HFxn use was independently associated with younger age, later year of diagnosis, non-black race, non-Medicaid insurance, non-Western residence, higher income, academic treatment facility, greater distance from treatment facility, low-risk disease group (by National Comprehensive Cancer Network criteria), and nonreceipt of hormone therapy.Although CFxn remains the most common radiation therapy schedule for localized PCa, use of HFxn appears to be increasing in the United States as a result of increased extreme HFxn use. Financial and logistical factors may accelerate adoption of shorter schedules. Considering the multiple demographic and prognostic differences identified between these groups, randomized outcome data comparing extreme HFxn to alternatives are desirable.

Conventional prostate cancer risk stratification results in considerable heterogeneity within each prognostic group. Men with pathologic grade Group 4 (Gleason score 8) but otherwise low-risk features have been identified as a favorable subset of high-risk prostate cancer. Given recent randomized data supporting improved cancer outcome with brachytherapy in intermediate- and high-risk prostate cancer, we sought to evaluate brachytherapy utilization and overall survival (OS) for these patients.We queried the National Cancer Database for clinical T1c-T2a N0 M0 prostate cancer with prostate-specific antigen10 ng/mL and Gleason score 8 adenocarcinoma on biopsy. All patients received androgen deprivation therapy and either external beam radiation therapy (EBRT) alone, brachytherapy alone, or a combination of EBRT with brachytherapy boost (brachytherapy + EBRT). Kaplan-Meier OS estimates as well as univariate and multivariate Cox proportional hazards regression analyses were performed. Propensity score-matched analyses were performed to further control for baseline confounders.Four thousand four hundred ninety-six patients were identified with a median followup of 62.5 months (range, 2.3-119.8). Median age was 72 years (range, 41-90+). Utilization of brachytherapy decreased from 2004 to 2009. The odds ratio for brachytherapy by year (continuous variable) was 0.86 (p 0.001). Five-year OS was 84%, 88%, and 89% for the EBRT alone, brachytherapy alone, and brachytherapy + EBRT groups, respectively. On multivariate analysis, higher median income, low comorbidity score, and treatment with brachytherapy alone (hazard ratio, 0.66; p = 0.005) or brachytherapy + EBRT (hazard ratio, 0.70; p = 0.001) remained associated with longer OS. Propensity score matching confirmed longer OS associated with either brachytherapy regimen.Of those men with World Health Organization pathologic grade Group 4 (Gleason score 8) prostate cancer and otherwise favorable prognostic features treated with androgen deprivation therapy and radiation therapy, longer OS was achieved when prostate brachytherapy was included, whether used alone or in combination with supplemental EBRT. In spite of these excellent outcomes, prostate brachytherapy utilization is declining in the United States.

Aim High fraction of scattered radiation in cone-beam CT (CBCT) imaging degrades CT number accuracy and visualization of low contrast objects. To suppress scatter in CBCT projections, we developed a focused, two-dimensional antiscatter grid (2DASG) prototype. In this work, we report on the primary and scatter transmission characteristics of the 2DASG prototype aimed for linac mounted, offset detector geometry CBCT systems in radiation therapy, and compared its performance to a conventional one-dimensional ASG (1DASG). Methods The 2DASG is an array through-holes separated by 0.1 mm septa that was fabricated from tungsten using additive manufacturing techniques. Through-holes’ focusing geometry was designed for offset detector CBCT in Varian TrueBeam system. Two types of ASGs were evaluated: a) a conventional 1DASG with a grid ratio of 10, b) the 2DASG prototype with a grid ratio of 8.2. To assess the scatter suppression performance of both ASGs, Scatter-to-primary ratio (SPR) and scatter transmission fraction (Ts) were measured using the beam stop method. Scatter and primary intensities were modulated by varying the phantom thickness between 10 and 40 cm. Additionally, the effect of air gap and bow tie (BT) filter on SPR and Ts were evaluated. Average primary transmission fraction (TP) and pixel specific primary transmission were also measured for both ASGs. To assess the effect of transmission characteristics on projection image signal-to-noise ratio (SNR) improvement factor was calculated. Improvement in contrast to noise ratio (CNR) was demonstrated using a low contrast object. Results In comparison to 1DASG, 2DASG reduced SPRs by a factor of 3 to 6 across the range of phantom setups investigated. Ts values for 1D and 2DASGs were in the range of 21 to 29%, and 5 to 14%, respectively. 2DASG continued to provide lower SPR and Ts at increased air gap and with BT filter. Tp of 1D and 2DASGs were 70.6% and 84.7%, respectively. Due to the septal shadow of the 2DASG, its pixel specific primary transmission values varied between 32.5% and 99.1%. With respect to 1DASG, 2DASG provided up to factor of 1.7 more improvement in SNR across the SPR range investigated. Moreover, 2DASG provided improved visualization of low contrast objects with respect to 1DASG and NOASG setups. Conclusions When compared to a conventional 1DASG, 2DASG prototype provided noticeably lower SPR and Ts values, indicating its superior scatter suppression performance. 2DASG also provided 19% higher average primary transmission that was attributed to the absence of interseptal spacers and optimized grid geometry. Our results indicate that the combined effect of lower scatter and higher primary transmission provided by 2DASG may potentially translate into more accurate CT numbers and improved contrast resolution in CBCT images. This article is protected by copyright. All rights reserved.

Purpose Stereotactic radiosurgery (SRS), whole-brain radiotherapy (WBRT), and epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are treatment options for brain metastases in patients with EGFR-mutant non–small-cell lung cancer (NSCLC). This multi-institutional analysis sought to determine the optimal management of patients with EGFR-mutant NSCLC who develop brain metastases and have not received EGFR-TKI. Materials and Methods A total of 351 patients from six institutions with EGFR-mutant NSCLC developed brain metastases and met inclusion criteria for the study. Exclusion criteria included prior EGFR-TKI use, EGFR-TKI resistance mutation, failure to receive EGFR-TKI after WBRT/SRS, or insufficient follow-up. Patients were treated with SRS followed by EGFR-TKI, WBRT followed by EGFR-TKI, or EGFR-TKI followed by SRS or WBRT at intracranial progression. Overall survival (OS) and intracranial progression-free survival were measured from the date of brain metastases. Results The median OS for the SRS (n = 100), WBRT (n = 120), and EGFR-TKI (n = 131) cohorts was 46, 30, and 25 months, respectively ( P < .001). On multivariable analysis, SRS versus EGFR-TKI, WBRT versus EGFR-TKI, age, performance status, EGFR exon 19 mutation, and absence of extracranial metastases were associated with improved OS. Although the SRS and EGFR-TKI cohorts shared similar prognostic features, the WBRT cohort was more likely to have a less favorable prognosis ( P = .001). Conclusion This multi-institutional analysis demonstrated that the use of upfront EGFR-TKI, and deferral of radiotherapy, is associated with inferior OS in patients with EGFR-mutant NSCLC who develop brain metastases. SRS followed by EGFR-TKI resulted in the longest OS and allowed patients to avoid the potential neurocognitive sequelae of WBRT. A prospective, multi-institutional randomized trial of SRS followed by EGFR-TKI versus EGFR-TKI followed by SRS at intracranial progression is urgently needed.

Purpose Automatic detection and identification of setup devices, using a deep convolutional neural network (CNN) for real time multi-class object detection, has the potential to reduce errors in the treatment delivery process by avoiding documentation errors. Methods A database of the setup device photos from the most recent 1200 patients treated at our institution was downloaded from the record and verify system (R&V) along with the corresponding set-up notes. Images were manually labelled with bounding boxes of each device. A real time object detection CNN using the 'you only look once' (YOLOv2) architecture was trained using transfer learning of a pre-trained CNN (ResNet50). The CNN was trained to detect and identify 11 of the most common treatment accessories used at our institution. Results Using transfer learning of a CNN for multi-class object detection, we are able to automatically detect and identify set-up devices in photographs with an accuracy of 96%. Conclusions Automation in radiation oncology has the potential to reduce risk. Automatic detection of setup devices is possible using a CNN and transfer learning. This work shows both the value of incident learning systems (ILS) in practice knowledge dissemination, and shows how automation of clinical processes and less reliance on manual documentation has the potential for risk reduction in radiation oncology treatments.