Prospective Evaluation of the Clinical Benefits of a Novel Tattoo-less Workflow for Nonspine Bone Stereotactic Body Radiation Therapy: Integrating Surface-Guidance With Triggered Imaging Reduces Treatment Time and Eliminates the Need for Tattoos.

PURPOSE: Oligometastatic disease has expanded the indications for nonspine bone stereotactic body radiation therapy (NSB SBRT). We investigated whether optical surface monitoring systems (OSMS) could enable tattoo-less setup and substitute for 2-dimensional/3-dimensional or cone beam computed tomography (CBCT)-based mid-imaging in NSB SBRT. METHODS AND MATERIALS: OSMS was incorporated in parallel with an existing workflow using pretreatment CBCT and 2-dimensional/3-dimensional kV/kV mid-imaging beginning November 2019. The ability of OSMS to detect out-of-tolerance (>2 mm/>2°) and commanded couch shifts was analyzed. A workflow incorporating OSMS reference captures, CBCT for pretreatment verification, and OSMS/triggered imaging (TI) for intrafraction monitoring was developed for rib/sternum SBRT beginning November 2021 and all NSB SBRT beginning February 2022. Treatment time and CBCT-related radiation dose between the OSMS and the non-OSMS intrafraction monitoring group was analyzed pre- and post-OSMS/TI workflow adoption. All fractions were analyzed through statistical process control with use of an XmR chart of treatment time per quarter from February 2019 to February 2023. Special cause rules were based on Institute for Healthcare Improvement criteria. RESULTS: From February 2019 to February 2023, 1993 NSB SBRT fractions were delivered, including 234 rib, 109 sternum, 214 ilium, and 682 multisite. Over 20 commanded shifts, OSMS could detect 2-mm shifts to within 0.4 mm 67% of the time and 0.8 mm 95% of the time. All NSB SBRT sites showed significant reductions in treatment time, including the greatest improvement in rib total treatment (21.6-13.4 minutes; P = 1.16 × 10-17) and beam time (7.9-3.2 minutes; P = 7.32 × 10-27). Significant reductions in CBCT-related radiation were also observed for several NSB sites. These process improvements were associated with OSMS adoption. CONCLUSIONS: Adoption of a novel NSB SBRT workflow incorporating OSMS/TI for bone intrafraction motion monitoring reduced treatment time and CBCT-related radiation exposure while also allowing for more continuous intrafraction motion monitoring for NSB SBRT. OSMS/TI enabled the transition to a tattoo-less workflow.

Feasibility of the Audio-Visual Assisted Therapeutic Ambience in Radiotherapy (AVATAR) System for Anesthesia Avoidance in Pediatric Patients: A Multicenter Trial.

PURPOSE: The Audio-Visual Assisted Therapeutic Ambience in Radiotherapy (AVATAR) system was the first published radiation therapy (RT)-compatible system to reduce the need for pediatric anesthesia through video-based distraction. We evaluated the feasibility of AVATAR implementation and effects on anesthesia use, quality of life, and anxiety in a multicenter pediatric trial. METHODS AND MATERIALS: Pediatric patients 3 to 10 years of age preparing to undergo RT at 10 institutions were prospectively enrolled. Children able to undergo at least 1 fraction of RT using AVATAR without anesthesia were considered successful (S). Patients requiring anesthesia for their entire treatment course were nonsuccessful (NS). The PedsQL3.0 Cancer Module (PedsQL) survey assessed quality of life and was administered to the patient and guardian at RT simulation, midway through RT, and at final treatment. The modified Yale Preoperative Anxiety Scale (mYPAS) assessed anxiety and was performed at the same 3 time points. Success was evaluated using the χ2 test. PedsQL and mYPAS scores were assessed using mixed effects models with time points evaluated as fixed effects and a random intercept on the subject. RESULTS: Eighty-one children were included; median age was 7 years. AVATAR was successful at all 10 institutions and with photon and proton RT. There were 63 (78%) S patients; anesthesia was avoided for a median of 20 fractions per patient. Success differed by age (P = .04) and private versus public insurance (P < .001). Both patient (P = .008) and parent (P = .006) PedsQL scores significantly improved over the course of RT for patients aged 5 to 7. Anxiety in the treatment room decreased for both S and NS patients over RT course (P < .001), by age (P < .001), and by S versus NS patients (P < .001). CONCLUSIONS: In this 10-center prospective trial, anesthesia avoidance with AVATAR was 78% in children aged 3 to 10 years, higher than among age-matched historical controls (49%; P < .001). AVATAR implementation is feasible across multiple institutions and should be further studied and made available to patients who may benefit from video-based distraction.

Prospective deployment of an automated implementation solution for artificial intelligence translation to clinical radiation oncology.

Introduction: Artificial intelligence (AI)-based technologies embody countless solutions in radiation oncology, yet translation of AI-assisted software tools to actual clinical environments remains unrealized. We present the Deep Learning On-Demand Assistant (DL-ODA), a fully automated, end-to-end clinical platform that enables AI interventions for any disease site featuring an automated model-training pipeline, auto-segmentations, and QA reporting. Materials and methods: We developed, tested, and prospectively deployed the DL-ODA system at a large university affiliated hospital center. Medical professionals activate the DL-ODA via two pathways (1): On-Demand, used for immediate AI decision support for a patient-specific treatment plan, and (2) Ambient, in which QA is provided for all daily radiotherapy (RT) plans by comparing DL segmentations with manual delineations and calculating the dosimetric impact. To demonstrate the implementation of a new anatomy segmentation, we used the model-training pipeline to generate a breast segmentation model based on a large clinical dataset. Additionally, the contour QA functionality of existing models was assessed using a retrospective cohort of 3,399 lung and 885 spine RT cases. Ambient QA was performed for various disease sites including spine RT and heart for dosimetric sparing. Results: Successful training of the breast model was completed in less than a day and resulted in clinically viable whole breast contours. For the retrospective analysis, we evaluated manual-versus-AI similarity for the ten most common structures. The DL-ODA detected high similarities in heart, lung, liver, and kidney delineations but lower for esophagus, trachea, stomach, and small bowel due largely to incomplete manual contouring. The deployed Ambient QAs for heart and spine sites have prospectively processed over 2,500 cases and 230 cases over 9 months and 5 months, respectively, automatically alerting the RT personnel. Discussion: The DL-ODA capabilities in providing universal AI interventions were demonstrated for On-Demand contour QA, DL segmentations, and automated model training, and confirmed successful integration of the system into a large academic radiotherapy department. The novelty of deploying the DL-ODA as a multi-modal, fully automated end-to-end AI clinical implementation solution marks a significant step towards a generalizable framework that leverages AI to improve the efficiency and reliability of RT systems.

Less Time Is Less Motion: Analysis of Practical Efficiencies Gained With a Modified Workflow Integrating Planar kV Midimaging With CBCT for Spine Stereotactic Body Radiation Therapy.

Purpose: Our purpose was to optimize an image guided radiation therapy (IGRT) workflow to achieve practical setup accuracy in spine stereotactic body radiation therapy (SBRT). We assessed the time-saving efficiencies gained from incorporating planar kV midimaging as a surrogate for cone beam computed tomography (CBCT) for intrafraction motion monitoring. Methods and Materials: We selected 5 thoracic spine SBRT patients treated in 5 fractions and analyzed patient shifts captured by a modified IGRT workflow using planar kV midimaging integrated with CBCT to maintain a tolerance of 1 mm and 1°. We determined the frequency at which kV midimaging captured intrafraction motion as validated on repeat CBCT and assessed the potential time and dosimetric advantages of our modified IGRT workflow. Results: Patient motion, detected as out-of-tolerance shifts on planar kV midimaging, occurred during 6 of 25 fractions (24%) and were validated on repeat CBCT 100% of the time. Observed intrafraction absolute shifts (mean ± standard deviation) for the 25 fractions were 0.39 ± 0.21, 0.56 ± 0.22, and 0.45 ± 0.21 mm for lateral-longitude-vertical translations and 0.38 ± 0.12°, 0.32 ± 0.09°, and 0.47 ± 0.14° for pitch-roll-yaw rotation, which if uncorrected, could have significantly affected target coverage and increased spinal cord dose. The average times for pretreatment imaging, midtreatment verification, and total treatment time were 8.94, 2.81, and 16.21 minutes. Our modified IGRT workflow reduced the total number of CBCTs required from 120 to 35 (70%) and imaging dose from 126.2 to 43.4 cGy (65.6%) while maintaining high fidelity for our patient population. Conclusions: Accurate patient positioning was effectively achieved with use of multiple 2-dimensional-3-dimensional kV images and an average of 1 verification CBCT scan per fraction. Integration of planar kV midimaging can effectively reduce treatment time associated with spine SBRT delivery and minimize the potential dosimetric effect of intrafraction motion on target coverage and spinal cord dose.

Cost of cardiac stereotactic body radioablation therapy versus catheter ablation for treatment of ventricular tachycardia.

AIMS: To compare the cost of cardiac stereotactic body radioablation therapy (SBRT) versus catheter ablation for treating ventricular tachycardia (VT). BACKGROUND: Cardiac SBRT is a novel way of treating refractory VT that may be less costly than catheter ablation, owing to its noninvasive, outpatient nature. However, the true costs of either procedure are not well described, which could help inform a more appropriate reimbursement for cardiac SBRT than simply cross-indexing existing procedural rates. METHODS: Process maps were derived for the full patient care cycle of both procedures using time-driven activity-based costing. Step-by-step timestamps were collected prospectively from a 10-patient SBRT cohort and retrospectively from a 59-patient catheter ablation cohort. Individual costs were estimated by multiplying timestamps with capacity cost rates (CCRs) for personnel, space, equipment, consumable, and indirect resources. These were summed into total cost, which for cardiac SBRT was compared with current catheter ablation and single-fraction lung SBRT reimbursements, both potential reference rates for cardiac SBRT. RESULTS: The direct and total procedural costs of cardiac SBRT ($7549 and $10,621) were 49% and 54% less than those of VT ablation ($14,707 and $23,225). These costs were significantly different from current reimbursement for catheter ablation ($22,692) and lung SBRT ($6329). After including hospitalization expenses (≥$15,000), VT ablation costs at least $27,604 more to furnish than cardiac SBRT. CONCLUSIONS: Time-driven activity-based costing (TDABC) can be a helpful tool for assessing healthcare costs, including novel treatment approaches. In addition to its clinical benefits, cardiac SBRT may provide significant cost reduction opportunities for treatment of VT.

Patient specific distortion detection and mitigation in MR images used for stereotactic radiosurgery.

Objective.In MRI-based radiation therapy planning, mitigating patient-specific distortion with standard high bandwidth scans can result in unnecessary sacrifices of signal to noise ratio. This study investigates a technique for distortion detection and mitigation on a patient specific basis.Approach.Fast B0 mapping was performed using a previously developed technique for high-resolution, large dynamic range field mapping without the need for phase unwrapping algorithms. A phantom study was performed to validate the method. Distortion mitigation was validated by reducing geometric distortion with increased acquisition bandwidth and confirmed by both the B0 mapping technique and manual measurements. Images and contours from 25 brain stereotactic radiosurgery patients and 95 targets were analyzed to estimate the range of geometric distortions expected in the brain and to estimate bandwidth required to keep all treatment targets within the ±0.5 mm iso-distortion contour.Main Results.The phantom study showed, at 3 T, the technique can measure distortions with a mean absolute error of 0.12 mm (0.18 ppm), and a maximum error of 0.37 mm (0.6 ppm). For image acquisition at 3 T and 1.0 mm resolution, mean absolute distortion under 0.5 mm in patients required bandwidths from 109 to 200 Hz px-1for patients with the least and most distortion, respectively. Maximum absolute distortion under 0.5 mm required bandwidths from 120 to 390 Hz px-1.Significance.The method for B0 mapping was shown to be valid and may be applied to assess distortion clinically. Future work will adapt the readout bandwidth to prospectively mitigate distortion with the goal to improve radiosurgery treatment outcomes by reducing healthy tissue exposure.

Substrate Modification Using Stereotactic Radioablation to Treat Refractory Ventricular Tachycardia in Patients With Ischemic Cardiomyopathy.

OBJECTIVES: This study aimed to determine the feasibility of using radioablation for arrhythmogenic a substrate modification. BACKGROUND: Stereotactic body radiation therapy (SBRT) is a promising therapy for ventricular tachycardia (VT) refractory to catheter ablation. METHODS: A total of 6 male patients (median age 72 years) with ischemic cardiomyopathy (left ventricular ejection fraction 20% [interquartile range (IQR): 16%-25%]) and VT refractory to antiarrhythmic medications and catheter ablations underwent SBRT to extensive scar substrate. In addition to electroanatomical mapping, 5 of 6 patients had computed tomography segmentation using MUSIC (IHU Liryc, Univ. Bordeaux and Inria Sophia Antipolis, France). Regions of wall thinning <5 mm, calcification, and intramyocardial fat were targeted for radioablation at 25 Gy. RESULTS: The median planning target volume was 319 (IQR: 280-330) mL. Device-treated or sustained VT episodes were not significantly reduced by radioablation (median 42 [IQR: 19-269] to 29 [IQR: 0-81]; P = 0.438). However, a reduction in device shocks was observed from 12 (IQR: 3-19) to 0 (IQR: 0-1) (P = 0.046). Over a follow-up period of 231 (IQR: 212-311) days, 3 patients died of end-stage heart failure and 3 of 6 patients had possible adverse events (heart failure exacerbation, pneumonia, and an asymptomatic pericardial effusion). CONCLUSIONS: Substrate modification using SBRT assisted by computed tomography segmentation is feasible for treatment of VT in patients with ischemic cardiomyopathy. Although a significant reduction in device shocks was observed, suboptimal VT burden reduction and significant mortality rate in this cohort of patients with advanced cardiomyopathy underscore the need to improve mechanistic understanding for antiarrhythmic effects to guide dosing and targeting of scar substrates.

Radiation Dose to the Intraprostatic Urethra Correlates Strongly With Urinary Toxicity After Prostate Stereotactic Body Radiation Therapy: A Combined Analysis of 23 Prospective Clinical Trials.

PURPOSE: Clinical trials assessing evaluation prostate stereotactic body radiation therapy (SBRT) have used a wide range of allowed doses to the intraprostatic urethra, but the relationship between urethral dose and urinary toxicity has not been thoroughly evaluated. The goal of this study was to characterize urinary toxicity outcomes according to urethral dose administered during prostate SBRT. METHODS AND MATERIALS: The MEDLINE (PubMed) database was searched for published prospective studies of prostate SBRT through August 2020 that documented a maximum urethral dose metric (MUDM). Reported acute and late urinary toxicity rates were collected. Logistic regression and weighted Pearson correlation models were used to assess associations between urinary toxicity rates and MUDM. RESULTS: Twenty-three unique studies (n = 2232 patients) met the inclusion criteria and included a wide range of MUDMs (equivalent dose in 2 Gy fractions [EQD2]: 69-141.75 Gy; α/ß = 3 Gy). The median follow-up ranged from 3 to 67 months (median, 32 months). On logistic regression analysis, the MUDM EQD2 was significantly associated with multiple urinary toxicity endpoints, including acute grade (G) 2+ (odds ratio [OR], 1.02; P < .001), late G2+ (OR, 1.03; P < .0001), and late G3+ (OR, 1.04; P = .003) urinary toxicity. On weighted Pearson correlation analysis, the MUDM was more closely associated with all evaluated urinary toxicity endpoints than prescription dose, including acute G2+ (r = 0.51; P = .02), late G2+ (r = 0.9; P < .0001), and late G3+ toxicity (r = 0.7; P = .003). Multivariate analysis accounting for age, prostate size, bladder dosimetry, and baseline urinary function confirmed associations between urinary outcomes and MUDM. Within the studied dose range, each increase of 1 Gy to the MUDM corresponded to a 0.8% and 1.0% increase in acute G2+ and late G2+ toxicity, respectively. CONCLUSIONS: Radiation dose to the urethra correlates closely with urinary toxicity in patients with prostate cancer treated with SBRT. Attention should be paid to the urethral dose when delivering prostate SBRT to high doses, and approaches for urethral dose reduction warrant further investigation.

Dosimetric Planning Tradeoffs to Reduce Heart Dose Using Machine Learning-Guided Decision Support Software in Patients with Lung Cancer.

PURPOSE: Cardiac toxicity is a well-recognized risk after radiation therapy (RT) in patients with non-small cell lung cancer (NSCLC). However, the extent to which treatment planning optimization can reduce mean heart dose (MHD) without untoward increases in lung dose is unknown. METHODS AND MATERIALS: Retrospective analysis of RT plans from 353 consecutive patients with locally advanced NSCLC treated with intensity modulated RT (IMRT) or 3-dimensional conformal RT. Commercially available machine learning-guided clinical decision support software was used to match RT plans. A leave-one-out predictive model was used to examine lung dosimetric tradeoffs necessary to achieve a MHD reduction. RESULTS: Of all 232 patients, 91 patients (39%) had RT plan matches showing potential MHD reductions of >4 to 8 Gy without violating the upper limit of lung dose constraints (lung volume [V] receiving 20 Gy (V20 Gy) <37%, V5 Gy <70%, and mean lung dose [MLD] <20 Gy). When switching to IMRT, 75 of 103 patients (72.8%) had plan matches demonstrating improved MHD (average 2.0 Gy reduction, P < .0001) without violating lung constraints. Examining specific lung dose tradeoffs, a mean ≥3.7 Gy MHD reduction was achieved with corresponding absolute increases in lung V20 Gy, V5 Gy, and MLD of 3.3%, 5.0%, and 1.0 Gy, respectively. CONCLUSIONS: Nearly 40% of RT plans overall, and 73% when switched to IMRT, were predicted to have reductions in MHD >4 Gy with potentially clinically acceptable tradeoffs in lung dose. These observations demonstrate that decision support software for optimizing heart-lung dosimetric tradeoffs is feasible and may identify patients who might benefit most from more advanced RT technologies.

A bi-institutional multi-disciplinary failure mode and effects analysis (FMEA) for a Co-60 based total body irradiation technique.

BACKGROUND: We aim to assess the risks associated with total body irradiation (TBI) delivered using a commercial dedicated Co-60 irradiator, and to evaluate inter-institutional and inter-professional variations in the estimation of these risks. METHODS: A failure mode and effects analysis (FMEA) was generated using guidance from the AAPM TG-100 report for quantitative estimation of prospective risk metrics. Thirteen radiation oncology professionals from two institutions rated possible failure modes (FMs) for occurrence (O), severity (S), and detectability (D) indices to generate a risk priority number (RPN). The FMs were ranked by descending RPN value. Absolute gross differences (AGD) in resulting RPN values and Jaccard Index (JI; for the top 20 FMs) were calculated. The results were compared between professions and institutions. RESULTS: A total of 87 potential FMs (57, 15, 10, 3, and 2 for treatment, quality assurance, planning, simulation, and logistics respectively) were identified and ranked, with individual RPN ranging between 1-420 and mean RPN values ranging between 6 and 74. The two institutions shared 6 of their respective top 20 FMs. For various institutional and professional comparison pairs, the number of common FMs in the top 20 FMs ranged from 6 to 13, with JI values of 18-48%. For the top 20 FMs, the trend in inter-professional variability was institution-specific. The mean AGD values ranged between 12.5 and 74.5 for various comparison pairs. AGD values differed the most for medical physicists (MPs) in comparison to other specialties i.e. radiation oncologists (ROs) and radiation therapists (RTs) [MPs-vs-ROs: 36.3 (standard deviation SD = 34.1); MPs-vs-RTs: 41.2 (SD = 37.9); ROs-vs-RTs: 12.5 (SD = 10.8)]. Trends in inter-professional AGD values were similar for both institutions. CONCLUSION: This inter-institutional comparison provides prospective risk analysis for a new treatment delivery unit and illustrates the institution-specific nature of FM prioritization, primarily due to operational differences. Despite being subjective in nature, the FMEA is a valuable tool to ensure the identification of the most significant risks, particularly when implementing a novel treatment modality. The creation of a bi-institutional, multidisciplinary FMEA for this unique TBI technique has not only helped identify potential risks but also served as an opportunity to evaluate clinical and safety practices from the perspective of both multiple professional roles and different institutions.

Cardiac stereotactic body radiation therapy for ventricular tachycardia: Current experience and technical gaps.

INTRODUCTION: Despite advances in drug and catheter ablation therapy, long-term recurrence rates for ventricular tachycardia remain suboptimal. Cardiac stereotactic body radiotherapy (SBRT) is a novel treatment that has demonstrated reduction of arrhythmia episodes and favorable short-term safety profile in treatment-refractory patients. Nevertheless, the current clinical experience is early and limited. Recent studies have highlighted variable duration of treatment effect and substantial recurrence rates several months postradiation. Contributing to these differential outcomes are disparate approaches groups have taken in planning and delivering radiation, owing to both technical and knowledge gaps limiting optimization and standardization of cardiac SBRT. METHODS AND FINDINGS: In this report, we review the historical basis for cardiac SBRT and existing clinical data. We then elucidate the current technical gaps in cardiac radioablation, incorporating the current clinical experience, and summarize the ongoing and needed efforts to resolve them. CONCLUSION: Cardiac SBRT is an emerging therapy that holds promise for the treatment of ventricular tachycardia. Technical gaps remain, to be addressed by ongoing research and growing clincial experience.

The Rapidly-Developing Area of Radiocardiology: Principles, Complications and Applications of Radiotherapy on the Heart.

Ventricular arrhythmias are the leading cause of sudden cardiac death. Current treatment strategies for ventricular tachycardia, including antiarrhythmic drugs and catheter ablation, have limited efficacy in patients with structural heart disease. Noninvasive ablation with the use of externally applied radiation (cardiac radioablation) has emerged as a promising and novel approach to treating recurrent ventricular tachycardias. However, the heart is generally an "organ at risk" for radiation treatments, such that very little is known on the effects of radiotherapy on cardiac ultrastructure and electrophysiologic properties. Furthermore, there has been limited interaction between the fields of cardiology and radiation oncology and physics. The advent of cardiac radioablation will undoubtedly increase interactions between cardiologists, cardiac electrophysiologists, radiation oncologists and physicists. There is an important knowledge gap separating these specialties, but scientific developments, technical optimisation, and improvements depend on intense multidisciplinary collaboration. This manuscript seeks to review the basic of radiation physics and biology for cardiovascular specialists in an effort to facilitate constructive scientific and clinical collaborations to improve patient outcomes.

Ultrasound-based sensors to monitor physiological motion.

PURPOSE: Medical procedures can be difficult to perform on anatomy that is constantly moving. Respiration displaces internal organs by up to several centimeters with respect to the surface of the body, and patients often have limited ability to hold their breath. Strategies to compensate for motion during diagnostic and therapeutic procedures require reliable information to be available. However, current devices often monitor respiration indirectly, through changes on the outline of the body, and they may be fixed to floors or ceilings, and thus unable to follow a given patient through different locations. Here we show that small ultrasound-based sensors referred to as "organ configuration motion" (OCM) sensors can be fixed to the abdomen and/or chest and provide information-rich, breathing-related signals. METHODS: By design, the proposed sensors are relatively inexpensive. Breathing waveforms were obtained from tissues at varying depths and/or using different sensor placements. Validation was performed against breathing waveforms derived from magnetic resonance imaging (MRI) and optical tracking signals in five and eight volunteers, respectively. RESULTS: Breathing waveforms from different modalities were scaled so they could be directly compared. Differences between waveforms were expressed in the form of a percentage, as compared to the amplitude of a typical breath. Expressed in this manner, for shallow tissues, OCM-derived waveforms on average differed from MRI and optical tracking results by 13.1% and 15.5%, respectively. CONCLUSION: The present results suggest that the proposed sensors provide measurements that properly characterize breathing states. While OCM-based waveforms from shallow tissues proved similar in terms of information content to those derived from MRI or optical tracking, OCM further captured depth-dependent and position-dependent (i.e., chest and abdomen) information. In time, the richer information content of OCM-based waveforms may enable better respiratory gating to be performed, to allow diagnostic and therapeutic equipment to perform at their best.

Deep-learning system to improve the quality and efficiency of volumetric heart segmentation for breast cancer.

Although artificial intelligence algorithms are often developed and applied for narrow tasks, their implementation in other medical settings could help to improve patient care. Here we assess whether a deep-learning system for volumetric heart segmentation on computed tomography (CT) scans developed in cardiovascular radiology can optimize treatment planning in radiation oncology. The system was trained using multi-center data (n = 858) with manual heart segmentations provided by cardiovascular radiologists. Validation of the system was performed in an independent real-world dataset of 5677 breast cancer patients treated with radiation therapy at the Dana-Farber/Brigham and Women's Cancer Center between 2008-2018. In a subset of 20 patients, the performance of the system was compared to eight radiation oncology experts by assessing segmentation time, agreement between experts, and accuracy with and without deep-learning assistance. To compare the performance to segmentations used in the clinic, concordance and failures (defined as Dice < 0.85) of the system were evaluated in the entire dataset. The system was successfully applied without retraining. With deep-learning assistance, segmentation time significantly decreased (4.0 min [IQR 3.1-5.0] vs. 2.0 min [IQR 1.3-3.5]; p < 0.001), and agreement increased (Dice 0.95 [IQR = 0.02]; vs. 0.97 [IQR = 0.02], p < 0.001). Expert accuracy was similar with and without deep-learning assistance (Dice 0.92 [IQR = 0.02] vs. 0.92 [IQR = 0.02]; p = 0.48), and not significantly different from deep-learning-only segmentations (Dice 0.92 [IQR = 0.02]; p ≥ 0.1). In comparison to real-world data, the system showed high concordance (Dice 0.89 [IQR = 0.06]) across 5677 patients and a significantly lower failure rate (p < 0.001). These results suggest that deep-learning algorithms can successfully be applied across medical specialties and improve clinical care beyond the original field of interest.

Association of Left Anterior Descending Coronary Artery Radiation Dose With Major Adverse Cardiac Events and Mortality in Patients With Non-Small Cell Lung Cancer.

IMPORTANCE: Radiotherapy accelerates coronary heart disease (CHD), but the dose to critical cardiac substructures has not been systematically studied in lung cancer. OBJECTIVE: To examine independent cardiac substructure radiotherapy factors for major adverse cardiac events (MACE) and all-cause mortality in patients with locally advanced non-small cell lung cancer (NSCLC). DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort analysis of 701 patients with locally advanced NSCLC treated with thoracic radiotherapy at Harvard University-affiliated hospitals between December 1, 2003, and January 27, 2014, was performed. Data analysis was conducted between January 12, 2019, and July 22, 2020. Cardiac substructures were manually delineated. Radiotherapy dose parameters (mean, maximum, and the volume [V, percentage] receiving a specific Gray [Gy] dose in 5-Gy increments) were calculated. Receiver operating curve and cut-point analyses estimating MACE (unstable angina, heart failure hospitalization or urgent visit, myocardial infarction, coronary revascularization, and cardiac death) were performed. Fine and Gray and Cox regressions were adjusted for preexisting CHD and other prognostic factors. MAIN OUTCOMES AND MEASURES: MACE and all-cause mortality. RESULTS: Of the 701 patients included in the analysis, 356 were men (50.8%). The median age was 65 years (interquartile range, 57-73 years). The optimal cut points for substructure and radiotherapy doses (highest C-index value) were left anterior descending (LAD) coronary artery V15 Gy greater than or equal to 10% (0.64), left circumflex coronary artery V15 Gy greater than or equal to 14% (0.64), left ventricle V15 Gy greater than or equal to 1% (0.64), and mean total coronary artery dose greater than or equal to 7 Gy (0.62). Adjusting for baseline CHD status and other prognostic factors, an LAD coronary artery V15 Gy greater than or equal to 10% was associated with increased risk of MACE (adjusted hazard ratio, 13.90; 95% CI, 1.23-157.21; P = .03) and all-cause mortality (adjusted hazard ratio, 1.58; 95% CI, 1.09-2.29; P = .02). Among patients without CHD, associations with increased 1-year MACE were noted for LAD coronary artery V15 Gy greater than or equal to 10% (4.9% vs 0%), left circumflex coronary artery V15 Gy greater than or equal to 14% (5.2% vs 0.7%), left ventricle V15 Gy greater than or equal to 1% (5.0% vs 0.4%), and mean total coronary artery dose greater than or equal to 7 Gy (4.8% vs 0%) (all P ≤ .001), but only a left ventricle V15 Gy greater than or equal to 1% increased the risk among patients with CHD (8.4% vs 4.1%; P = .046). Among patients without CHD, 2-year all-cause mortality was increased with an LAD coronary artery V15 Gy greater than or equal to 10% (51.2% vs 42.2%; P = .009) and mean total coronary artery dose greater than or equal to 7 Gy (53.2% vs 40.0%; P = .01). CONCLUSIONS AND RELEVANCE: The findings of this cohort study suggest that optimal cardiac dose constraints may differ based on preexisting CHD. Although the LAD coronary artery V15 Gy greater than or equal to 10% appeared to be an independent estimator of the probability of MACE and all-cause mortality, particularly in patients without CHD, left ventricle V15 Gy greater than or equal to 1% appeared to confer an increased risk of MACE among patients with CHD. These constraints are worthy of further study because there is a need for improved cardiac risk stratification and aggressive risk mitigation strategies.

Treating the SARS-CoV-2-positive patient with cancer: A proposal for a pragmatic and transparent ethical process.

The treatment of patients with cancer who test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses unique challenges. In this commentary, the authors describe the ethical rationale and implementation details for the creation of a novel, multidisciplinary treatment prioritization committee, including physicians, frontline staff, an ethicist, and an infectious disease expert. Organizational obligations to health care workers also are discussed. The treatment prioritization committee sets a threshold of acceptable harm to patients from decreased cancer control that is justified to reduce risk to staff. The creation of an ethical, consistent, and transparent decision-making process involving such frontline stakeholders is essential as departments across the country are faced with decisions regarding the treatment of SARS-CoV-2-positive patients with cancer.

Fibrillar Collagen Quantification With Curvelet Transform Based Computational Methods.

Quantification of fibrillar collagen organization has given new insight into the possible role of collagen topology in many diseases and has also identified candidate image-based bio-markers in breast cancer and pancreatic cancer. We have been developing collagen quantification tools based on the curvelet transform (CT) algorithm and have demonstrated this to be a powerful multiscale image representation method due to its unique features in collagen image denoising and fiber edge enhancement. In this paper, we present our CT-based collagen quantification software platform with a focus on new features and also giving a detailed description of curvelet-based fiber representation. These new features include C++-based code optimization for fast individual fiber tracking, Java-based synthetic fiber generator module for method validation, automatic tumor boundary generation for fiber relative quantification, parallel computing for large-scale batch mode processing, region-of-interest analysis for user-specified quantification, and pre- and post-processing modules for individual fiber visualization. We present a validation of the tracking of individual fibers and fiber orientations by using synthesized fibers generated by the synthetic fiber generator. In addition, we provide a comparison of the fiber orientation calculation on pancreatic tissue images between our tool and three other quantitative approaches. Lastly, we demonstrate the use of our software tool for the automatic tumor boundary creation and the relative alignment quantification of collagen fibers in human breast cancer pathology images, as well as the alignment quantification of in vivo mouse xenograft breast cancer images.

Technical Note: Quality assurance and relative dosimetry testing of a 60 Co total body irradiator using optical imaging.

PURPOSE: The aim of this study was to create an optical imaging-based system for quality assurance (QA) testing of a dedicated Co-60 total body irradiation (TBI) machine. Our goal is to streamline the QA process by minimizing the amount time necessary for tests such as verification of dose rate and field homogeneity. METHODS: Plastic scintillating rods were placed directly on the patient treatment couch of a dedicated TBI 60 Co irradiator. A tripod-mounted intensified camera was placed directly adjacent to the couch. Images were acquired over a 30-s period once the cobalt source was fully exposed. Real-time image filtering was used; cumulative images were flatfield corrected as well as background and darkfield subtracted. Scintillators were used to measure light-radiation field correspondence, dose rate, field homogeneity, and symmetry. Dose rate effects were measured by modifying the height of the treatment couch and scintillator response was compared to ionization chamber (IC) measurements. Optically stimulated luminesce detector (OSLD) used as reference dosimeters during field symmetry and homogeneity testing. RESULTS: The scintillator-based system accurately reported changes in dose rate. When comparing normalized output values for IC vs scintillators over a range of source-to-surface distances, a linear relationship (R2  = 0.99) was observed. Normalized scintillator signal matched OSLD measurements with <1.5% difference during field homogeneity and symmetry testing. Beam symmetry across both axes of the field was within 2%. The light field was found to correspond to 90 ± 3% of the isodose maximum along the longitudinal and latitudinal axis, respectively. Scintillator imaging output results using a single image stack requiring no postexposure processing (needed for OSLD) or repeat manual measurements (needed for IC). CONCLUSION: Imaging of scintillation light emission from plastic rods is a viable and efficient method for carrying out TBI 60 Co irradiator QA. We have shown that this technique can accurately measure field homogeneity, symmetry, light-radiation field correspondence, and dose rate effects.