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A first‐time survey across 15 cancer centers in Ontario, Canada, on the current practice of patient‐specific quality assurance (PSQA) for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) delivery was conducted. The objectives were to assess the current state of PSQA practice, identify areas for potential improvement, and facilitate the continued improvement in standardization, consistency, efficacy, and efficiency of PSQA regionally. The survey asked 40 questions related to PSQA practice for IMRT/VMAT delivery. The questions addressed PSQA policy and procedure, delivery log evaluation, instrumentation, measurement setup and methodology, data analysis and interpretation, documentation, process, failure modes, and feedback. The focus of this survey was on PSQA activities related to routine IMRT/VMAT treatments on conventional linacs, including stereotactic body radiation therapy but excluding stereotactic radiosurgery. The participating centers were instructed to submit answers that reflected the collective view or opinion of their department and represented the most typical process practiced. The results of the survey provided a snapshot of the current state of PSQA practice in Ontario and demonstrated considerable variations in the practice. A large majority (80%) of centers performed PSQA measurements on all VMAT plans. Most employed pseudo‐3D array detectors with a true composite (TC) geometry. No standard approach was found for stopping or reducing frequency of measurements. The sole use of delivery log evaluation was not widely implemented, though most centers expressed interest in adopting this technology. All used the Gamma evaluation method for analyzing PSQA measurements; however, no universal approach was reported on how Gamma evaluation and pass determination criteria were determined. All or some PSQA results were reviewed regularly in two‐thirds of the centers. Planning related issues were considered the most frequent source for PSQA failures (40%), whereas the most frequent course of action for a failed PSQA was to review the result and decide whether to proceed to treatment.

Purpose: Peer review is an essential quality assurance component of radiation therapy planning. A growing body of literature has demonstrated substantial rates of suggested plan changes resulting from peer review. There remains a paucity of data on the impact of peer review rounds for stereotactic body radiation therapy (SBRT). We therefore aim to evaluate the outcomes of peer review in this specific patient cohort. Methods and materials: We conducted a retrospective review of all SBRT cases that underwent peer review from July 2015 to June 2018 at a single institution. Weekly peer review rounds are grouped according to cancer subsite and attended by radiation oncologists, medical physicists and medical radiation technologists. We prospectively compiled ‘learning moments’, defined as cases with suggested changes or where an educational discussion occurred beyond routine management, and critical errors, defined as errors which could alter clinical outcomes, recorded prospectively during peer review. Plan changes implemented after peer review were documented. Results: Nine hundred thirty-four SBRT cases were included. The most common treatment sites were lung (518, 55%), liver (196, 21%) and spine (119, 13%). Learning moments were identified in 161 cases (17%) and translated into plan changes in 28 cases (3%). Two critical errors (0.2%) were identified: an inadequate planning target volume margin and an incorrect image set used for contouring. There was a statistically significantly higher rate of learning moments for lower-volume SBRT sites (defined as ≤30 cases/year) versus higher-volume SBRT sites (29% vs 16%, respectively; p = 0.001). Conclusions: Peer review for SBRT cases revealed a low rate of critical errors, but did result in implemented plan changes in 3% of cases, and either educational discussion or suggestions of plan changes in 17% of cases. All SBRT sites appear to benefit from peer review, though lower-volume sites may require particular attention.

Background and purpose Sampling theory and operator characteristic curves are methods that can determine an optimal schedule for quality control tests. We apply this method to positional data for whole breast radiotherapy since several surveys report inconsistent image guidance practice for this technique. Materials and methods Positional errors were defined, for 55 consecutive breast cancer patients, by comparing the central lung distance measured on portal images with that obtained from the corresponding digitally reconstructed radiograph. From the distribution of positional errors, the probability of a setup error >5 mm in the direction of the mediastinum was established. Using operator characteristic curves, we compared the effectiveness of various image-guidance schedules in dealing with such errors. We also calculated the dosimetric impact of undetected errors. Results Setup errors >5 mm towards the mediastinum for this cohort were unlikely, at 2.7%. Imaging half of the fractions protects most patients against three or more undetected errors. Undetected, such an error increases, on average, the maximum dose to 10 cm3 of the heart by 50 cGy, the mean heart dose by 4 cGy, and the left lung V20Gy by 0.2%; therefore, the clinical impact is minute. Given that detected positional errors outside of tolerance are corrected, their residual likelihood decreases with the ratio of fractions being imaged. Conclusions For most tangential breast radiotherapy patients, setup errors >5 mm towards the mediastinum are unlikely, and their dosimetric impact is remote. Imaging half of the fractions of a course of whole breast radiotherapy prevents these errors to occur more than twice.

The efficacy of MR-guided radiotherapy on a MR-LINAC (MR-L) is dependent on the geometric accuracy of its MR images over clinically relevant Fields-of-View (FOVs). Our objectives were to: evaluate gradient non-linearity (GNL) on the Elekta Unity MR-L across time via 76 weekly measurements of 3D-distortion over concentrically larger diameter spherical volumes (DSVs); quantify distortion measurement error; and assess the temporal stability of spatial distortion using statistical process control (SPC).MR-image distortion was assessed using a large-FOV 3D-phantom containing 1932 markers embedded in seven parallel plates, spaced 25 mm × 25 mm in- and 55 mm through-plane. Automatically analyzed T1 images yielded distortions in 200, 300, 400 and 500 mm concentric DSVs. Distortion measurement error was evaluated using median absolute difference analysis of imaging repeatability tests.Over the measurement period absolute time-averaged distortion varied between: dr = 0.30 - 0.49 mm, 0.53 - 0.80 mm, 1.0 - 1.4 mm and 2.28 - 2.37 mm, for DSVs 200, 300, 400 and 500 mm at the 98Image distortion on the MR-L is in the sub-millimeter range for DSVs ≤ 300 mm and stable across time, with SPC analysis indicating all measurements remain within control for each DSV.

Diagnostic and evidential static image, video clip, and sound multimedia are captured during routine clinical care in cardiology, dermatology, ophthalmology, pathology, physiatry, radiation oncology, radiology, endoscopic procedural specialties, and other medical disciplines. Providers typically describe the multimedia findings in contemporaneous electronic health record clinical notes or associate a textual interpretative report. Visual communication aids commonly used to connect, synthesize, and supplement multimedia and descriptive text outside medicine remain technically challenging to integrate into patient care. Such beneficial interactive elements may include hyperlinks between text, multimedia elements, alphanumeric and geometric annotations, tables, graphs, timelines, diagrams, anatomic maps, and hyperlinks to external educational references that patients or provider consumers may find valuable. This HIMSS-SIIM Enterprise Imaging Community workgroup white paper outlines the current and desired clinical future state of interactive multimedia reporting (IMR). The workgroup adopted a consensus definition of IMR as “interactive medical documentation that combines clinical images, videos, sound, imaging metadata, and/or image annotations with text, typographic emphases, tables, graphs, event timelines, anatomic maps, hyperlinks, and/or educational resources to optimize communication between medical professionals, and between medical professionals and their patients.” This white paper also serves as a precursor for future efforts toward solving technical issues impeding routine interactive multimedia report creation and ingestion into electronic health records.

Introduction Patients with non-small cell lung cancer (NSCLC) can experience rapid disease progression between initial staging FDG-PET scans and commencement of curative-intent radiotherapy (RT). Previous studies that estimated stage migration rates by comparing staging PET/CT and treatment-planning PET/CT images were limited by small sample sizes. Methods This multicenter, international study combined prospective data from five institutions for PET-staged patients with NSCLC who were intended to receive curative-intent RT. TNM status was compared for staging and RT planning scans and the probability of TNM status and overall stage migration was analyzed as a function of the interval between PET/CT scans. The impacts of N classification, overall stage, and pathology were also studied. Results Pooled data from 181 patients were analyzed. The median interval between PET/CT scans was 42 days (range, 2–208). Upstaging occurred in 32 % of patients. The overall rate of stage migration was higher for patients presenting with initial stage IIIB/IIIC disease (p = 0.006) and patients with N2−3 nodal disease (p = 0.019). Upstaging to M1 disease was significantly associated with initial stage IIIB/IIIC disease (HR = 15.2) and adenocarcinoma (HR = 10) histology. Conclusion Longer intervals between imaging and treatment in patients with NSCLC were associated with high rates disease progression with consequent risks of geographic miss in RT planning and futile treatment in patients with M1 disease. Patients with more extensive initial nodal involvement and those with adenocarcinoma had the highest rates of stage migration. Dedicated RT planning PET/CT imaging is recommended, especially if >3 weeks have elapsed after initial staging.

We explain the rationale for metabolically adaptive radiation dose escalation in stage III non-small-cell lung cancer and describe the design of a Canadian phase II randomized trial investigating this approach. In the trial, patients are randomized to either conventional chemoradiation treatment (60 Gy in 30 fractions) or metabolically adaptive chemoradiation, where fluorodeoxyglucose-avid tumor sub-volumes receive an integrated boost dose to a maximum of 85 Gy in 30 fractions. The trial sample size is 78 patients, and the target population is patients with newly diagnosed, inoperable stage III non-small-cell lung cancer treated with radical intent chemoradiation. The primary objective of the trial is to determine if dose escalation to metabolically active sub-volumes will reduce 2-year local-regional failure rate from 42.3% to 22.3%, when compared with standard treatment. The secondary objectives are to determine the effect of dose escalation on overall survival, progression-free survival, quality of life, and rate of grade 3 to 5 toxicities.

The Canadian Organization of Medical Physicists (COMP), in close partnership with the Canadian Partnership for Quality Radiotherapy (CPQR) has developed a series of Technical Quality Control (TQC) guidelines for radiation treatment equipment. These guidelines outline the performance objectives that equipment should meet in order to ensure an acceptable level of radiation treatment quality. The TQC guidelines have been rigorously reviewed and field tested in a variety of Canadian radiation treatment facilities. The development process enables rapid review and update to keep the guidelines current with changes in technology. This announcement provides an introduction to the guidelines, describing their scope and how they should be interpreted. Details of recommended tests can be found in separate, equipment specific TQC guidelines published in the JACMP (COMP Reports), or the website of the Canadian Partnership for Quality Radiotherapy (www.cpqr.ca).

A FDG-PET/CT image feature with optimal prognostic potential for locally-advanced non-small cell lung cancer (LA-NSCLC) patients has yet to be identified, and neither has the optimal time for FDG-PET/CT response assessment; furthermore, nodal features have been largely ignored in the literature. We propose to identify image features or imaging time point with maximal prognostic power.Consecutive consenting patients with LA-NSCLC receiving curative intent CRT were enrolled. 4DPET/4DCT scans were acquired 0, 2, 4, and 7 weeks during IMRT treatment. Eleven image features and their rates of change were recorded for each time point and tested for each of the possible outcome 2 years post CRT using the Kaplan-Meier method.32 consecutive patients were recruited, 27 completing all scans. Restricting analysis to 4DPET/4DCT features and rates of change with p 0.005, several volume-based features and their rates of change reached significance. Image features involving nodal disease were the only ones associated with overall survival.Several 4DPET/CT features and rates of change can reach significant association (p 0.005) with outcomes, including overall survival, at many time points. The optimal time for adaptive CRT is therefore not constrained uniquely on imaging.

A close partnership between the Canadian Partnership for Quality Radiotherapy (CPQR) and the Canadian Organization of Medical Physicist's (COMP) Quality Assurance and Radiation Safety Advisory Committee (QARSAC) has resulted in the development of a suite of Technical Quality Control (TQC) guidelines for radiation treatment equipment; they outline specific performance objectives and criteria that equipment should meet in order to assure an acceptable level of radiation treatment quality. The adopted framework for the development and maintenance of the TQCs ensures the guidelines incorporate input from the medical physics community during development, measures the workload required to perform the QC tests outlined in each TQC, and remain relevant (i.e., “living documents”) through subsequent planned reviews and updates. The framework includes consolidation of existing guidelines and/or literature by expert reviewers, structured stages of public review, external field‐testing, and ratification by COMP. This TQC development framework is a cross‐country initiative that allows for rapid development of robust, community‐driven living guideline documents that are owned by the community and reviewed to keep relevant in a rapidly evolving technical environment. Community engagement and uptake survey data shows 70% of Canadian centers are part of this process and that the data in the guideline documents reflect, and are influencing, the way Canadian radiation treatment centers run their technical quality control programs. For a medium‐sized center comprising six linear accelerators and a comprehensive brachytherapy program, we evaluate the physics workload to 1.5 full‐time equivalent physicists per year to complete all QC tests listed in this suite. PACS number(s): 87.55.Qr, 87.56.Fc, 87.56.‐v

Purpose Incident investigation, reporting, and learning are core elements of quality improvement in radiation treatment. This report describes the development of a Canadian National System for Incident Reporting in Radiation Treatment (NSIR-RT), focusing especially on the taxonomy. Methods and materials The NSIR-RT was developed to provide a framework in Canada for reporting and analyzing radiation treatment incidents. A key objective was to assure compatibility with other international reporting systems to facilitate future information exchange. The Canadian community was engaged at every step of the development process through Delphi consensus building and inter-user agreement testing to promote awareness of the system and motivate broad-based utilization across the country. Results The final taxonomy was comprised of 6 data groups (impact, discovery, patient, details, treatment delivery, and investigation) and 33 data categories with predefined menu options. There was a high level agreement within the Canadian community about the final suite of data categories, and broad alignment of these categories with the World Health Organization and other American and European radiation treatment incident classifications. Conclusions The Canadian NSIR-RT taxonomy will be implemented as an online, web-based reporting and analysis system. It is expected that the taxonomy will evolve and mature over time to meet the changing needs of the Canadian radiation treatment community and support radiation treatment incident learning on a global scale.

Introduction Treatment of locally advanced non–small cell lung cancer with chemoradiotherapy (CRT) is limited by development of toxicity in normal tissue, including radiation esophagitis (RE). Increasingly, 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is being used for adaptive planning. Our aim was to assess changes in esophageal FDG uptake during CRT and relate the changes to the onset and severity of RE. Methods This prospective study in patients with stage II–III non–small cell lung cancer involved serial four-dimensional computed tomography and PET scans during CRT (60–74Gy). RE was recorded weekly using the Common Terminology Criteria for Adverse Events (v4.0), and imaging was performed at weeks 0, 2, 4, and 7. Changes in the esophagus's peak standard uptake value (SUV peak ) were analyzed for each time point and correlated with grade of RE using the Wilcoxon rank-sum test. The volume of esophagus receiving 50 Gy (V50) and volume of esophagus receiving 60 Gy (V60) were correlated with the development of RE, and the C-statistic (area under the curve [AUC]) was calculated to measure predictivity of grade 3 RE. Results RE developed in 20 of 27 patients (74%), with grade 3 reached in 6 (22%). A significant percentage increase in SUV peak in the patients with RE was noted at week 4 ( p = 0.01) and week 7 ( p = 0.03). For grade 3 RE, a significant percentage increase in SUV peak was noted at week 2 ( p = 0.01) and week 7 ( p = 0.03) compared with that for less than grade 3 RE. Median V50 (46.3%) and V60 (33.4%) were significantly higher in patients with RE ( p = 0.04). The AUC measurements suggested that the percentage change in SUV peak at week 2 (AUC = 0.69) and V50 (AUC = 0.67) and V60 (AUC = 0.66) were similarly predictive of grade 3 RE. Conclusions Serial FDG-PET images during CRT show significant increases in SUV peak for patients in whom RE develops. The changes at week 2 may predict those at risk for the development of grade 3 RE and may be informative for adaptive planning and early intervention.

224 Background: Adverse drug events are common in ambulatory oncology where care spans multiple providers and medication documentation is often poor. We undertook a QI project with the aim of having 30% of patients have a best possible medication history (BPMH) or medication reconciliation (MedRec) documented within 30 days of starting systemic therapy. Methods: An Electronic Medical record-Integrated Tool (EMITT) was developed to facilitate documentation. 2 Plan-Do-Study-Act (PDSA) cycles have been completed to date; PDSA 1 consisted of piloting EMITT in 3 clinics run by physician champions. PDSA 2 which consisted of expanding pharmacy support and addition of a 4th clinic was impacted by care changes related to COVID. The proportion of patients with BPMH/MedRec documented in EMITT was calculated monthly for each period (PDSA 1, PDSA 2 pre-COVID and PDSA 2 post-COVID). The balancing measure of time to complete an entry was evaluated through a time motion study. Results: Between 9/9/2019 and 31/5/2020, 9.4% (233/2488) of patients had BPMH/MedRec completed; Table shows proportion of patients by month. BPMH and MedRec were most frequently performed by pharmacists followed by pharmacy students and nurses. On average, it took 5.5 minutes to complete an entry (n = 10; median number of medications per patient = 12.3). Conclusions: BPMH was documented more often than MedRec. While some usage was sustained, the changes to care as a result of COVID-19 negatively impacted ambulatory medication reconciliation. Future PDSA cycles will involve engaging patients in MedRec and extending EMITT to all ambulatory cancer clinics where medication management is a major component of care. [Table: see text]

Purpose: Functional image guided intensity-modulated radiation therapy has the potential to improve cancer treatment quality by basing treatment parameters such as heterogeneous dose distributions information derived from imaging. However, such heterogeneous dose distributions are subject to imaging uncertainty. In this paper, the authors develop a robust optimization model to design plans that are desensitized to imaging uncertainty. Methods: Starting from the pretreatment fluorodeoxyglucose-positron emission tomography scans, the authors use the raw voxel standard uptake values (SUVs) as input into a series of intermediate functions to transform the SUV into a desired dose. The calculated desired doses were used as an input into a robust optimization model to generate beamlet intensities. For each voxel, the authors assume that the true SUV cannot be observed but instead resides in an interval centered on the nominal (i.e., observed) SUV. Then the authors evaluated the nominal and robust solutions through a simulation study. The simulation considered the effect of the true SUV being different from the nominal SUV on the quality of the treatment plan. Treatment plans were compared on the metrics of objective function value and tumor control probability (TCP). Results: Computational results demonstrate the potential for improvements in tumor control probability and deviation from the desired dose distribution compared to a nonrobust model while maintaining acceptable tissue dose. Conclusions: Robust optimization can help design treatment plans that are more stable in the presence of image value uncertainties.

Purpose: There is evidence that computed tomography (CT) and positron emission tomography (PET) imaging metrics are prognostic and predictive in nonsmall cell lung cancer (NSCLC) treatment outcomes. However, few studies have explored the use of standardized uptake value (SUV)-based image features of nodal regions as predictive features. The authors investigated and compared the use of tumor and node image features extracted from the radiotherapy target volumes to predict relapse in a cohort of NSCLC patients undergoing chemoradiation treatment. Methods: A prospective cohort of 25 patients with locally advanced NSCLC underwent 4DPET/4DCT imaging for radiation planning. Thirty-seven image features were derived from the CT-defined volumes and SUVs of the PET image from both the tumor and nodal target regions. The machine learning methods of logistic regression and repeated stratified five-fold cross-validation (CV) were used to predict local and overall relapses in 2 yr. The authors used well-known feature selection methods (Spearman’s rank correlation, recursive feature elimination) within each fold of CV. Classifiers were ranked on their Matthew’s correlation coefficient (MCC) after CV. Area under the curve, sensitivity, and specificity values are also presented. Results: For predicting local relapse, the best classifier found had a mean MCC of 0.07 and was composed of eight tumor features. For predicting overall relapse, the best classifier found had a mean MCC of 0.29 and was composed of a single feature: the volume greater than 0.5 times the maximum SUV (N). Conclusions: The best classifier for predicting local relapse had only tumor features. In contrast, the best classifier for predicting overall relapse included a node feature. Overall, the methods showed that nodes add value in predicting overall relapse but not local relapse.

IntroductionSimulation has been effective for changing attitudes towards team-based competencies in many areas, but its role in teaching interprofessional collaboration (IPC) in radiation medicine (RM) is unknown. This study reports on feasibility and IPC outcomes of a team-based simulation event; ‘Radiation Medicine Simulation in Learning Interprofessional Collaborative Experience’ (RM SLICE).MethodsRadiation therapy (RTT), medical physics (MP) and radiation oncology (RO) trainees in a single academic department were eligible. Scheduled closure of a modern RM clinic allowed rotation of five high-fidelity cases in three 105-minute timeslots. A pre/post-survey design evaluated learner satisfaction and interprofessional perceptions. Scales included the Readiness for Interprofessional Learning Scale (RIPLS), UWE Entry Level Interprofessional Questionnaire (UWEIQ), Trainee Test of Team Dynamics and Collaborative Behaviours Scale (CBS).ResultsTwenty-one trainees participated; six ROs (28·57%), six MPs (28·57%) and nine RTTs (42·86%). All cases were conducted, resolved and debriefed within the allotted time. Twenty-one complete sets (100%) of evaluations were returned. Participants reported limited interaction with other professional groups before RM SLICE. Perceptions of team functioning and value of team interaction in ‘establishing or improving the care plan’ were high for all cases, averaging 8·1/10 and 8·9/10. Average CBS scores were 70·4, 71·9 and 69·5, for the three cases, scores increasing between the first and second case for 13/21 (61·9%) participants. RIPLS and UWEIQ scores reflected positive perceptions both pre- and post-event, averaging 83·5 and 85·2 (RIPLS) and 60·6 and 55·7 (UWEIQ), respectively. For all professions for both scales, the average change in score reflected improved IP perceptions, with agreement between scales for 15/20 (75·0%) participants. Overall, perception of IPC averaged 9·14/10, as did the importance of holding such an event annually.ConclusionsTeam-based simulation is feasible in RM and appears to facilitate interprofessional competency-building in high-acuity clinical situations, reflecting positive perceptions of IPC.

The availability of respiratory synchronized PET (4DPET) imaging has enabled more accurate analysis of metabolic response since motion blur is minimized. We present our preliminary analysis of serial FDG 4DPET images acquired at weeks 0, 2, 4, and 7 during radiotherapy of seven stage II–IIINSCLC patients. The tumor and nodal PTV of the week 0 images restrained a 4DPET image thresholding algorithm to automatically contour SUV levels ranging from 20 to 80% of the maximum SUV, creating an intensity volume histogram (IVH) for each week. These contours allowed analysis of PET volumes and standard PET metrics such as SUVmax and SUVmean. We found a trend for decreasing SUVmax and SUVmean over a treatment course in both the tumor and nodal regions. On average, the SUVmax within the tumor decreased by 17±13% (1 SD) after 2 weeks, 30±13% after 4 weeks, and 39±19% after 7 weeks of radiotherapy. Decreasing volume trends were also observed in the 20 to 80% max SUV autocontours, ranging from 26±29% to 50±40% respectively, over 7 weeks of treatment. Only one patient demonstrated an increase in FDG uptake within the tumor volume between week 0 and week 2 of treatment, and was also the only patient to recur locally at 3 months following treatment. Changes in tumor metabolism over the course of advanced NSCLCradiotherapy are quantifiable with serial FDG 4DPET imaging. Preliminary analysis suggests that variations in these trends could be useful in identifying non‐responding patients that may require an alternative radiotherapeutic approach.

Objective: To determine the geometric accuracy of conventional and stereotactic lungradiotherapy using cone‐beam CTimage guidance, and assess the efficacy of these image‐guidedradiation therapy(IGRT) processes. Materials and Methods:IGRT was first used for our stereotactic lung program, where high geometric accuracy is required to deliver high doses in few fractions. The initial positional accuracy for 47 patients was assessed by registering daily CBCT to the planning CT; the patient position was corrected when the CBCT indicated discrepancies > ± 3 mm in any direction. For 19 of these patients, a second CBCT was acquired to assess the residual error. IGRT was also used to assess the initial and residual errors for lungcancer patients treated conventionally with (14 pts; 584 CBCT) and without (25 pts; 1032 CBCT) a remote‐controlled treatment couch. Systematic (Σ) and random (σ) positional errors were assessed for these three groups. Results: For stereotactic lung patients, Σ and σ ranged between 4.1 and 6.1 mm. IGRT reduces these errors to 1.2–1.9 mm, raising the proportion of patients within ± 3 mm from 16% to 82%. For conventional lungcancer patients, Σ and σ ranged between 1.4 and 3.8 mm, and IGRT raises the proportion of patients within ± 3 mm from 27% to 67%, with the remote‐controlled couch further improving this proportion to 84%. Conclusion:IGRT clearly confirms the high geometric accuracy required for stereotactic lung patients. This new paradigm has been transported to patients with locally‐advanced lungcancer, with similar accuracy.

Purpose To correlate radiation dose to the risk of severe radiologically-evident radiation-induced lung injury (RRLI) using voxel-by-voxel analysis of the follow-up computed tomography (CT) of patients treated for lung cancer with hypofractionated helical Tomotherapy. Methods and materials The follow-up CT scans from 32 lung cancer patients treated with various regimens (5, 8, and 25 fractions) were registered to pre-treatment CT using deformable image registration (DIR). The change in density was calculated for each voxel within the combined lungs minus the planning target volume (PTV). Parameters of a Probit formula were derived by fitting the occurrences of changes of density in voxels greater than 0.361 g cm −3 to the radiation dose. The model’s predictive capability was assessed using the area under receiver operating characteristic curve (AUC), the Kolmogorov-Smirnov test for goodness-of-fit, and the permutation test (P test ). Results The best-fit parameters for prediction of RRLI 6 months post RT were D 50 of 73.0 (95% CI 59.2.4–85.3.7) Gy, and m of 0.41 (0.39–0.46) for hypofractionated (5 and 8 fractions) and D 50 of 96.8 (76.9–123.9) Gy, and m of 0.36 (0.34–0.39) for 25 fractions RT. According to the goodness-of-fit test the null hypothesis of modeled and observed occurrence of RRLI coming from the same distribution could not be rejected. The AUC was 0.581 (0.575–0.583) for fractionated and 0.579 (0.577–0.581) for hypofractionated patients. The predictive models had AUC>upper 95% band of the P test . Conclusions The correlation of voxel-by-voxel density increase with dose can be used as a support tool for differential diagnosis of tumor from benign changes in the follow-up of lung IMRT patients.

Purpose To describe the incidence and type of brachytherapy patient safety events over 10 years in an academic brachytherapy program. Methods and Materials Brachytherapy patient safety events reported between January 2007 and August 2016 were retrieved from the incident reporting system and reclassified using the recently developed National System for Incident Reporting in Radiation Treatment taxonomy. A multi-incident analysis was conducted to identify common themes and key learning points. Results During the study period, 3095 patients received 4967 brachytherapy fractions. An additional 179 patients had MR-guided prostate biopsies without treatment as part of an interventional research program. A total of 94 brachytherapy- or biopsy-related safety events (incidents, near misses, or programmatic hazards) were identified, corresponding to a rate of 2.8% of brachytherapy patients, 1.7% of brachytherapy fractions, and 3.4% of patients undergoing MR-guided prostate biopsy. Fifty-one (54%) events were classified as actual incidents, 29 (31%) as near misses, and 14 (15%) as programmatic hazards. Two events were associated with moderate acute medical harm or dosimetric severity, and two were associated with high dosimetric severity. Multi-incident analysis identified five high-risk activities or clinical scenarios as follows: (1) uncommon, low-volume or newly implemented brachytherapy procedures, (2) real-time MR-guided brachytherapy or biopsy procedures, (3) use of in-house devices or software, (4) manual data entry, and (5) patient scheduling and handoffs. Conclusions Brachytherapy is a safe treatment and associated with a low rate of patient safety events. Effective incident management is a key element of continuous quality improvement and patient safety in brachytherapy.

Purpose To characterize nonrespiratory stomach motion in the fasting state and postprandial. Methods and materials Ten healthy volunteers underwent 2-dimensional Fiesta cine magnetic resonance imaging studies in 30-second voluntary breath hold, in axial, coronal, and 2 oblique planes while fasting, and 5, 15, 30, 45, and 60 minutes postmeal. Each stomach contour was delineated and sampled with 200 points. Matching points were found for all contours in the same 30-second acquisition. Using deformable parametric analysis (Matlab, version 7.1), mean magnitude, and standard deviation of displacement of each point were determined for each patient. Maximal, minimal, and median population values in 6 cardinal, and in any direction, were calculated. Results The median of mean displacements for the baseline position of each point was small and rarely exceeded 1.1 mm; greatest value was 1.6 mm superior–inferior. Median displacement (pooled across time) in the right–left, superior–inferior, and anterior–posterior directions was 0.3 (range, −0.7 to 1.3), 0.8 (−0.4 to 2.4), and 0.3 (−1.1 to 1.6) mm, respectively. Fasting and postprandial standard deviation did not differ. Conclusions Nonrespiratory stomach displacement is small and stomach position is stable after a small, standard meal. Radiation therapy may be delivered at any time within the first hour after eating without significant compromise of planned planning target volumes.

248 Background: Substantial work has been done to implement medication reconciliation (MedRec) in the inpatient setting to reduce medical errors and drug discrepancies. However, this work has not extended to the ambulatory cancer setting, where care spans multiple providers and responsibility remains unclear. We undertook an environmental scan to understand current MedRec practices in ambulatory cancer care across Canada. Methods: Semi-structured telephone interviews were conducted with stakeholders from institutions across Canada during a 2-month period in 2019. Questionnaires were pre-circulated to participants to guide discussions. Questions probed participants on processes, policies, roles and responsibilities, definitions of target populations, information sources, and barriers and facilitators. Results: 21 of the 23 stakeholders contacted were interviewed, representing 9 of 10 Provinces. Most institutions had a process in place for collecting best possible medication history (BPMH; 81%); however, considerable variation in practice was noted and full MedRec was uncommon. Of those institutions with a process, BPMH was most often undertaken by a pharmacist or pharmacy tech (53%) using a comprehensive Provincial drug information system (65%) as a starting point, and targeted patients initiating systemic therapy (59%). Few institutions (22%) routinely collected performance measures evaluating the process or outcomes. Lack of resources (physical, human and financial), high patient volumes, and access to medication records from external institutions and community pharmacies were identified as significant barriers to routinely collecting BPMH. Understanding the value added, clinician buy-in, and patient education regarding the importance of bringing medication to the clinic were identified as facilitators. Leveraging patients to more actively participate in collection and maintenance of their own medication records was identified as an area for future work. Conclusions: While most centres were doing BPMH in some patients, MedRec was uncommon in the ambulatory cancer setting. Results indicate a lack of consensus regarding best practices for medication management in ambulatory cancer care.

Purpose To evaluate the influence of tumor size, prescription dose, and dose to the lungs on posttreatment pulmonary function test (PFT) changes after stereotactic body radiation therapy (SBRT) for early-stage non-small cell lung cancer (NSCLC). Methods and Materials The analysis is based on 191 patients treated at 5 international institutions: inclusion criteria were availability of pre- and post-SBRT PFTs and dose-volume histograms of the lung and planning target volume (PTV); patients treated with more than 1 SBRT course were excluded. Correlation between early (1-6 months, median 3 months) and late (7-24 months, median 12 months) PFT changes and tumor size, planning target volume (PTV) dose, and lung doses was assessed using linear regression analysis, receiver operating characteristics analysis, and Lyman's normal tissue complication probability model. The PTV doses were converted to biologically effective doses and lung doses to 2 Gy equivalent doses before correlation analyses. Results Up to 6 months after SBRT, forced expiratory volume in 1 second and carbon monoxide diffusion capacity changed by −1.4% (95% confidence interval [CI], −3.4% to 0) and −7.6% (95% CI, −10.2% to −3.4%) compared with pretreatment values, respectively. A modest decrease in PFTs was observed 7-24 months after SBRT, with changes of −8.1% (95% CI, −13.3% to −5.3%) and −12.4% (95% CI, −15.5% to −6.9%), respectively. Using linear regression analysis, receiver operating characteristic analysis, and normal tissue complication probability modeling, all evaluated parameters of tumor size, PTV dose, mean lung dose, and absolute and relative volumes of the lung exposed to minimum doses of 5-70 Gy were not correlated with early and late PFT changes. Subgroup analysis based on pre-SBRT PFTs (greater or equal and less than median) did not identify any dose-effect relationship. Conclusions This study failed to demonstrate a significant dose-effect relationship for changes of pulmonary function after SBRT for early-stage non-small cell lung cancer.

Introduction:We report lung stereotactic-body radiotherapy (SBRT) outcomes for a large pooled cohort treated using daily online cone-beam computed tomography.Methods:Five hundred and five stage I–IIB (T1-3N0M0) non–small-cell lung cancer (NSCLC) cases underwent SBRT using cone-beam computed tomography image guidance at five international institutions from 1998 to 2010. Median age was 74 years (range, 42–92) whereas median forced expiratory volume in 1 second/diffusing lung capacity for carbon monoxide were 1.4 liter (65%) and 10.8 ml/min/mmHg (53%). Of the 505 cases, 64% were biopsy proven and 87% medically inoperable. Staging was: IA 63%, IB 33%, IIA 2%, and recurrent 1%. Median max tumor dimension was 2.6 cm (range, 0.9–8.5). Median heterogeneously calculated volumetric prescription dose (PD) was 54 Gy (range, 20–64 Gy) in three fractions (range, 1–15) over 8 days (range, 1–27). Median biologically equivalent PD biological equivalent doses (BED10) was 132 Gy (range, 60–180).Results:With a median follow-up of 1.6 years (range, 0.1–7.3), the 2-year Kaplan–Meier local control (LC), regional control, and distant metastasis (DM) rates were 94%, 89%, and 20%, respectively, whereas cause-specific and overall survival were 87% and 60% (78% operable, 58% inoperable, p = 0.01), respectively. Stage, gross-tumor volume size (≥ 2.7 cm) and PD(BED10) predicted local relapse (LR) and DM. LR was 15% for BED10 less than 105 Gy versus 4% for BED10 of 105 Gy or more (p < 0.001); DM was 31% versus 18% for BED10 less than 105 versus 105 Gy or more (p = 0.01). On multivariate analysis, PD(BED10) and elapsed days during radiotherapy predicted LR; gross-tumor volume size predicted DM. Grade 2 or higher pneumonitis, rib fracture, myositis, and dermatitis were 7%, 3%, 1%, and 2%, respectively.Conclusions:In the largest early-stage NSCLC SBRT data set to date, a high rate of local control was achieved, which was correlated with a PD(BED10) of 105 Gy or more. Failures were primarily distant, severe toxicities were rare, and overall survival was encouraging in operable patients.

Purpose: Commercial CT-based image-guided radiotherapy (IGRT) systems allow widespread management of geometric variations in patient setup and internal organ motion. This document provides consensus recommendations for quality assurance protocols that ensure patient safety and patient treatment fidelity for such systems. Methods: The AAPM TG-179 reviews clinical implementation and quality assurance aspects for commercially available CT-based IGRT, each with their unique capabilities and underlying physics. The systems described are kilovolt and megavolt cone-beam CT, fan-beam MVCT, and CT-on-rails. A summary of the literature describing current clinical usage is also provided. Results: This report proposes a generic quality assurance program for CT-based IGRT systems in an effort to provide a vendor-independent program for clinical users. Published data from long-term, repeated quality control tests form the basis of the proposed test frequencies and tolerances. Conclusion: A program for quality control of CT-based image-guidance systems has been produced, with focus on geometry, image quality, image dose, system operation, and safety. Agreement and clarification with respect to reports from the AAPM TG-101, TG-104, TG-142, and TG-148 has been addressed.

Introduction: To evaluate the influence of pretreatment pulmonary function (PF) on survival, early and late pulmonary toxicity after stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer. Methods: Four hundred eighty-three patients with 505 tumors of early-stage non-small cell lung cancer cT1‐3 cN0 were treated with image-guided SBRT at five international institutions (1998‐2010). Sixty-four percent of the tumors were biopsy-proven and 18Ffluorodeoxyglucose-positron emission tomography was performed for staging in 84%. Image-guided SBRT was performed with a median of three fractions to a median total dose of 54 Gy. Pretreatment PF was available for 423 patients, and 617 posttreatment PF tests from 270 patients were available. Results: A large variability of pretreatment PF was observed: the 90% range of forced expiratory volume in 1 second and diffusing capacity for carbon monoxide was 29 to 109% and 5.5 to 19.1 ml/min/mmHg, respectively. PF was significantly correlated with overall survival but not cause-specific survival: diffusing capacity for carbon monoxide of 11.2 ml/min/mmHg differentiated between 3-year overall survival of 66% and 42%. Radiation-induced pneumonitis grade II occurred in 7% of patients and was not increased in patients with lower PF. A significant and progressive change of PF was observed after SBRT: PF decreased by 3.6% and 6.8% on average within 6 and 6 to 24 months after SBRT, respectively. Changes of PF after SBRT were significantly correlated with pretreatment PF: PF improved for worst pretreatment PF and the largest loss was observed for best pretreatment PF. Conclusions: Image-guided SBRT is safe in terms of acute and chronic pulmonary toxicity even for patients with severe pulmonary comorbidities. SBRT should be considered as a curative treatment option for inoperable patients with pretreatment PF as reported in this study.

Purpose To present the results of stereotactic body radiotherapy (SBRT) for medically inoperable patients with Stage I non–small-cell lung cancer (NSCLC) and contrast outcomes in patients with and without a pathologic diagnosis. Methods and Materials Between December 2004 and October 2008, 108 patients (114 tumors) underwent treatment according to the prospective research ethics board-approved SBRT protocols at our cancer center. Of the 108 patients, 88 (81.5%) had undergone pretreatment whole-body [18F]-fluorodeoxyglucose positron emission tomography/computed tomography. A pathologic diagnosis was unavailable for 33 (28.9%) of the 114 lesions. The SBRT schedules included 48 Gy in 4 fractions or 54–60 Gy in 3 fractions for peripheral lesions and 50–60 Gy in 8–10 fractions for central lesions. Toxicity and radiologic response were assessed at the 3–6-month follow-up visits using conventional criteria. Results The mean tumor diameter was 2.4-cm (range, 0.9–5.7). The median follow-up was 19.1 months (range, 1–55.7). The estimated local control rate at 1 and 4 years was 92% (95% confidence interval [CI], 86–97%) and 89% (95% CI, 81–96%). The cause-specific survival rate at 1 and 4 years was 92% (95% CI, 87–98%) and 77% (95% CI, 64–89%), respectively. No statistically significant difference was found in the local, regional, and distant control between patients with and without pathologically confirmed NSCLC. The most common acute toxicity was Grade 1 or 2 fatigue (53 of 108 patients). No toxicities of Grade 4 or greater were identified. Conclusions Lung SBRT for early-stage NSCLC resulted in excellent local control and cause-specific survival with minimal toxicity. The disease-specific outcomes were comparable for patients with and without a pathologic diagnosis. SBRT can be considered an option for selected patients with proven or presumed early-stage NSCLC.

Aims Computed tomography (CT)-based radiotherapy dose escalation for locally advanced non-small cell lung cancer (LA-NSCLC) has had limited success. In this planning study, we investigated the potential for adaptive dose escalation using respiratory-gated 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography scans (4DPET/4DCT) acquired before and during a course of chemoradiotherapy (CRT). Materials and methods We prospectively enrolled patients with LA-NSCLC receiving curative intent CRT. Radiotherapy was delivered using intensity-modulated radiotherapy (IMRT) using the week 0 4DCT scan. Three alternative, dose-escalated IMRT plans were developed offline based on the week 0, 2 and 4 4DPET/4DCT scans. The FDG-avid primary (PET-T) and nodal disease (PET-N) volumes defined by the 50% of maximum standard uptake value threshold were dose escalated to as high as possible while respecting organ at risk constraints. Results Thirty-two patients were recruited, 27 completing all scans. Twenty-five patients (93%) were boosted successfully above the clinical plan doses at week 0, 23 (85%) at week 2 and 20 (74%) at week 4. The median dose received by 95% of the planning target volume (D95) at week 0, 2 and 4 to PET-T were 74.4 Gy, 75.3 Gy and 74.1 Gy and to PET-N were 74.3 Gy, 71.0 Gy and 69.5 Gy. Conclusions Using 18F-FDG-4DPET/4DCT, it is feasible to dose escalate both primary and nodal disease in most patients. Choosing week 0 images to plan a course with an integrated boost to PET-avid disease allows for more patients to be successfully dose escalated with the highest boost dose.

The early response of lung tumours to stereotactic radiotherapy was prospectively evaluated with 18F-fluorodeoxyglucose positron emission tomography-computed tomography. Three months after treatment, the maximum standardised uptake value and the tumour diameter fell by 64 and 30%, respectively. This imaging strategy therefore remains under ongoing evaluation with the aim of identifying predictive and prognostic factors.

Purpose To examine incident rates in external beam radiation therapy (RT) as significant changes in technology were introduced. Materials and methods From 2001 to 2007, several technological and practice enhancements were made. All treatment incident reports, including near misses (from 2004), were classified, under a research ethics board approval, according to type (prescription or geometry), cause (location, documentation, non-compliance, laterality, prescribed change, human error, planning/dosimetry, software/hardware malfunction, and accessory), and clinical impact (none, minor, moderate, and severe). Trend analysis was performed retrospectively. Results One thousand and sixty three reports were analyzed. The average incident rate per 100 RT course was 1.7±0.4; excluding near misses, this rate fell to 1.4±0.3. Both rates showed a downward trend. The occurrence of events due to treatment accessories (0.75–0.28), prescribed changes to treatment parameters (0.17–0.03), and location (0.41–0.17) have decreased, while documentation-related incidents have risen (0.03–0.37). The proportion of incidents is highest at the planning and treatment stages. Conclusion Our analysis has shown that while technological and process enhancements can reduce certain error pathways, others can be created. Trends in incident rates have been assessed, indicating robustness of our practice in view of these changes.

The design, construction and application of a multimodality, 3D magnetic resonance/computed tomography (MR/CT) image distortion phantom and analysis system for stereotactic radiosurgery (SRS) is presented. The phantom is characterized by (1) a 1 × 1 × 1 (cm)3 MRI/CT-visible 3D-Cartesian grid; (2) 2002 grid vertices that are 3D-intersections of MR-/CT-visible 'lines' in all three orthogonal planes; (3) a 3D-grid that is MR-signal positive/CT-signal negative; (4) a vertex distribution sufficiently 'dense' to characterize geometrical parameters properly, and (5) a grid/vertex resolution consistent with SRS localization accuracy. When positioned correctly, successive 3D-vertex planes along any orthogonal axis of the phantom appear as 1 × 1 (cm)2-2D grids, whereas between vertex planes, images are defined by 1 × 1 (cm)2-2D arrays of signal points. Image distortion is evaluated using a centroid algorithm that automatically identifies the center of each 3D-intersection and then calculates the deviations dx, dy, dz and dr for each vertex point; the results are presented as a color-coded 2D or 3D distribution of deviations. The phantom components and 3D-grid are machined to sub-millimeter accuracy, making the device uniquely suited to SRS applications; as such, we present it here in a form adapted for use with a Leksell stereotactic frame. Imaging reproducibility was assessed via repeated phantom imaging across ten back-to-back scans; 80%-90% of the differences in vertex deviations dx, dy, dz and dr between successive 3 T MRI scans were found to be ⩽0.05 mm for both axial and coronal acquisitions, and over >95% of the differences were observed to be ⩽0.05 mm for repeated CT scans, clearly demonstrating excellent reproducibility. Applications of the 3D-phantom/analysis system are presented, using a 32-month time-course assessment of image distortion/gradient stability and statistical control chart for 1.5 T and 3 T GE TwinSpeed MRI systems.