Risk analysis of the Unity 1.5 T MR-Linac adapt-to-position workflow.

BACKGROUND AND PURPOSE: Newer technologies allow for daily treatment adaptation, providing the ability to account for setup variations and organ motion but comes at the cost of increasing the treatment workflow complexity. One such technology is the adapt-to-position (ATP) workflow on the Unity MR-Linac. Prospective risk assessment of a new workflow allows clinics to catch errors before they occur, especially for processes that include novel and unfamiliar steps. METHODS: As part of a quality management program, failure modes and effects analysis was performed on the ATP treatment workflow following the recommendations of AAPM's Task Group 100. A multidisciplinary team was formed to identify and evaluate failure modes for all the steps taken during a daily treatment workflow. Failure modes of high severity and overall score were isolated and addressed. RESULTS: Mitigations were determined for high-ranking failure modes and implemented into the clinic. High-ranking failure modes existed in all steps of the workflow. Failure modes were then rescored to evaluate the effectiveness of the mitigations. CONCLUSION: Failure modes and effects analysis on the Unity MR-Linac highlighted areas in the ATP workflow that could be prone to failures and allowed our clinic to change the process to be more robust.

Disponibilité de l'information médicale requise pour la déclaration d'une réaction indésirable médicamenteuse à Santé Canada: une étude exploratoire.

Background: Since 2019, health care facilities have been required to report serious adverse drug reactions (ADRs) to Health Canada. Objectives: To describe the availability of information required for reporting an ADR to Health Canada from medical records using 2 methods (systematic and in-depth reporting) and to compare the time required to find the information. Methods: This retrospective and prospective descriptive study involved serious ADRs occurring in a mother-child centre and reported between April 1, 2021, and March 31, 2023. The variables needed to complete the Health Canada reporting form were collected using 2 distinct methods. Results: Among the 270 serious ADRs reported retrospectively, 140 were sampled. The average availability of variables was 82.3% (standard deviation [SD] 11.3%), with average data collection time of 50 (SD 25) minutes. For the prospective part of the study, 15 serious ADRs were studied. The availability of variables was 82.8% (SD 6.9%) and 91.9% (SD 7.8%), for systematic and in-depth reporting, respectively, with data collection times of 44 (SD 17) and 130 (SD 33) minutes, respectively. Conclusions: The challenge of finding, in patients' medical records, all of the information needed for reporting an ADR to Health Canada required an in-depth approach. However, the in-depth method took 3 times as long as a search limited to places in the record where specific information should be found. To improve record keeping, additional training for clinicians could be considered and, potentially, development of a computerized clinical record that includes a dedicated form for documenting ADRs.

Contexte: Depuis 2019, les établissements de santé doivent déclarer les réactions indésirables graves aux médicaments (RIM graves) à Santé Canada. Objectifs: Décrire la disponibilité de l'information requise pour la déclaration d'une RIM à Santé Canada dans les dossiers médicaux par deux méthodes (soit, systématique et approfondie) et comparer le temps nécessaire pour retrouver l'information. Méthode: Étude descriptive rétrospective et prospective des RIM graves survenues en centre mère-enfant et déclarées entre le 1er avril 2021 et 31 mars 2023. Les variables nécessaires pour remplir le formulaire de déclaration de Santé Canada ont été collectées par deux méthodes distinctes. Résultats: Parmi les 270 RIM graves déclarées en rétrospectif, 140 ont été échantillonnées. La disponibilité moyenne des variables était de 82,3 % (écart-type [SD] 11,3 %), pour une durée de collecte de 50 (SD 25) minutes. Du côté prospectif, 15 RIM graves ont été étudiées, la disponibilité des variables était, pour chacune des méthodes respectivement, de 82,8 (SD 6,9 %) et 91,9 (SD 7,8 %), pour des temps de collecte respectifs de 44 (SD 17) et 130 (SD 33) minutes. Conclusions: La difficulté que représente l'identification de toutes les informations requises dans les dossiers médicaux pour la déclaration d'une RIM à Santé Canada nécessite une recherche approfondie. Toutefois, la recherche approfondie demande trois fois plus de temps qu'une recherche qui se limiterait aux endroits où l'information devrait se retrouver. Il est possible d'envisager de dispenser une formation supplémentaire aux cliniciens pour améliorer la tenue de dossiers et, éventuellement, le recours à un dossier clinique informatisé qui comprend un formulaire dédié à la documentation des RIM.

Factors associated with the withdrawal of life-sustaining therapies in patients with severe traumatic brain injury: a multicenter cohort study.

PURPOSE: To identify factors associated with decisions to withdraw life-sustaining therapies in patients with severe traumatic brain injury (TBI). MATERIALS AND METHODS: We conducted a 2-year multicenter retrospective cohort study (2005-2006) in mechanically ventilated patients aged 16 years and older admitted to the intensive care units (ICUs) of six Canadian level I trauma centers following severe TBI. One hundred and twenty charts were randomly selected at each center (n = 720). Data on ICU management strategies, patients' clinical condition, surgical procedures, diagnostic imaging, and decision to withdraw life-sustaining therapies were collected. The association of factors pertaining to the injury, interventions, and management strategies with decisions to withdraw life-sustaining therapies was evaluated among non-survivors. RESULTS: Among the 228 non-survivors, 160 died following withdrawal of life-sustaining therapies. Patients were predominantly male (69.7 %) with a mean age of 50.7 (±21.7) years old. Brain herniation was more often reported in patients who died following decisions to withdraw life-sustaining therapies (odds ratio [OR] 2.91, 95 % confidence interval [CI] 1.16-7.30, p = 0.02) compared to those who died due to other causes (e.g., cardiac arrest, shock, etc.). Epidural hematomas (OR 0.18, 95 % CI 0.06-0.56, p < 0.01), craniotomies (OR 0.12, 95 % CI 0.02-0.68, p = 0.02), and other non-neurosurgical procedures (OR 0.08, 95 % CI 0.02-0.43, p < 0.01) were less often associated with death following withdrawal of life-sustaining therapies than death from other causes. CONCLUSIONS: Death following decisions to withdraw life-sustaining therapies is associated with specific patient and clinical factors, and the intensity of care.

Training workload in the investigational drug service of a university hospital center.

PURPOSE: Training represents a considerable portion of research activities and is vastly different for each clinical trial. This variation is partially explained by the lack of detailed regulations surrounding training procedures, which hinders the ability of investigational drug service (IDS) staff to plan their workload. The aim of this study was to quantify the workload associated with trial-specific training of IDS staff. The secondary aim was to identify the factors associated with training complexity. METHODS: A retrospective study was carried out in the IDS of a mother and child university hospital. Trial-specific documents on which the pharmacy staff was trained were analyzed. Workload was calculated by measuring reading time. The readability of each document was determined by the Flesch Reading Ease score. The complexity of the trials was established using the scoring method of Calvin-Lamas et al. The influence of the following factors on training was assessed by analysis of variance: sponsor type, research phase, and research focus by medical specialty. RESULTS: A total of 93 clinical trials and 433 documents were included. Investigator's brochures were the longest (a mean [SD] of 107 [46] pages; P < 0.0001) and most difficult documents to read (mean [SD] readability score, 25.5 [4.4]; P < 0.0001). Trials with industry sponsors required a significantly longer overall reading time (mean [SD], 12.26 [6.72] hours; P < 0.0001). On average, a mean (SD) of 9.42 (7.16) hours of reading were necessary to train one employee for a clinical trial. CONCLUSION: This study is the first to document reading time necessary for training of IDS staff. The training workload varied by sponsor type, while the research phase and medical specialty had little impact. IDS units would benefit from a tool that could identify complex trials.

HDR prostate brachytherapy plan robustness and its effect on in-vivo source tracking error thresholds: A multi-institutional study.

PURPOSE: The purpose of this study was to examine the effect of departmental planning techniques on appropriate in-vivo source tracking error thresholds for high dose rate (HDR) prostate brachytherapy (BT) treatments, and to determine if a single in-vivo source tracking error threshold would be appropriate for the same patient anatomy. METHODS: The prostate, rectum, and urethra were contoured on a single patient transrectal ultrasound (TRUS) dataset. Anonymized DICOM files were disseminated to 16 departments who created an HDR prostate BT treatment plan on the dataset with a prescription dose of 15 Gy in a single fraction. Departments were asked to follow their own local treatment planning guidelines. Source positioning errors were then simulated in the 16 treatment plans and the effect on dose-volume histogram (DVH) indices calculated. Change in DVH indices were used to determine appropriate in-vivo source tracking error thresholds. Plans were considered to require intervention if the following DVH conditions occurred: prostate V100% < 90%, urethra D0.1cc > 118%, and rectumtt Dmax > 80%. RESULTS: There was wide variation in appropriate in-vivo source tracking error thresholds among the 16 participating departments, ranging from 1 to 6 mm. Appropriate in-vivo source tracking error thresholds were also found to depend on the direction of the source positioning error and the endpoint. A robustness parameter was derived, and found to correlate with the sensitivity of plans to source positioning errors. CONCLUSIONS: A single HDR prostate BT in-vivo source tracking error threshold cannot be applied across multiple departments, even for the same patient anatomy. The burden on in-vivo source tracking devices may be eased through improving HDR prostate BT plan robustness during the plan optimisation phase.

Cardiac Sparing with Personalized Treatment Planning for Early-stage Left Breast Cancer.

Purpose To compare cardiac doses of different whole-breast optimization schemes including free-breathing (FB) tangential radiotherapy (TRT), deep-inspiration breath-hold (DIBH) TRT, and FB helical tomotherapy (HT). Methods Early-stage left-sided breast cancer patients who underwent breast-conserving surgery followed by adjuvant radiotherapy were included in the study. Planning images included FB and DIBH CT scans acquired in the same supine treatment position with both arms abducted. A hypofractionated regimen of 42.5 Gy in 16 fractions was used. Clinical target volume delineation was aided through the use of a radio-opaque wire. A 7-mm margin was used in generating the planning target volumes. TRT plans were generated both in FB and DIBH. For the FB tomotherapy technique, a first plan (Tomo 1) was optimized limiting the maximum contralateral breast dose to 3.1 Gy. A second tomotherapy plan (Tomo 2) focused on the reduction of the mean heart dose without controlling the contralateral breast dose. All plans were optimized to obtain an equivalent planning target volume (PTV) coverage of ≥95% of the prescribed dose while minimizing the dose to organs at risk. Results Twenty-three patients treated between October 2012 and March 2016 were included in this retrospective study. Eleven patients (48%) had at least one major cardiovascular risk factors including one patient (4%) with a history of myocardial infarction. Six patients (26%) had been exposed to cardiotoxic chemotherapy agents. The average mean dose to the heart was 3.1 Gy with FB TRT, 1.1 with DIBH TRT, 2.4 Gy for Tomo 1, and 1.5 Gy for Tomo 2. The mean dose to the left anterior descending artery was 27.0 Gy, 8.0 Gy, 13.7 Gy and 6.6 Gy for FB TRT, DIBH TRT, Tomo 1 and Tomo 2 plans respectively. Conclusion Different cardiac-sparing optimization schemes are possible when treating left breast cancer. Although DIBH offers clear mean heart dose reductions, tomotherapy can be an interesting alternative treatment modality to spare the heart and coronary vessels, notably in patients who cannot comply with DIBH.

Helical Tomotherapy for Postmastectomy Radiotherapy after Immediate Left Breast Reconstruction: A Case Study.

A 43-year-old premenopausal female presented with a multicentric infiltrating lobular carcinoma of the left breast with axillary nodes metastasis. She underwent modified radical mastectomy with axillary lymph node dissection (level I and II) followed by a mixed autologous latissimus dorsi flap reconstruction with the addition of prosthesis. The final pathological analysis revealed a 6 cm invasive lobular carcinoma pT3N2aM0, grade III/III, estrogen and progesterone positive, human epidermal growth factor receptor 2 (HER2) negative, with 5/16 positive lymph nodes. She received neoadjuvant chemotherapy with doxorubicin and cyclophosphamide followed by paclitaxel. Post-mastectomy radiotherapy with axillary, supraclavicular and internal mammary lymph nodes (IMLN) irradiation was delivered to a dose of 50 Gy/25 fx. In this case with multiple risk factors for radiation-induced cardiac toxicity (left-sided lesion, internal mammary lymph nodes (IMLN) irradiation), we discuss the role of helical tomotherapy as a treatment alternative to conventional tangential radiotherapy.

Improved tissue assignment using dual-energy computed tomography in low-dose rate prostate brachytherapy for Monte Carlo dose calculation.

PURPOSE: An improvement in tissue assignment for low-dose rate brachytherapy (LDRB) patients using more accurate Monte Carlo (MC) dose calculation was accomplished with a metallic artifact reduction (MAR) method specific to dual-energy computed tomography (DECT). METHODS: The proposed MAR algorithm followed a four-step procedure. The first step involved applying a weighted blend of both DECT scans (I H/L) to generate a new image (I Mix). This action minimized Hounsfield unit (HU) variations surrounding the brachytherapy seeds. In the second step, the mean HU of the prostate in I Mix was calculated and shifted toward the mean HU of the two original DECT images (I H/L). The third step involved smoothing the newly shifted I Mix and the two original I H/L, followed by a subtraction of both, generating an image that represented the metallic artifact (I A,(H/L)) of reduced noise levels. The final step consisted of subtracting the original I H/L from the newly generated I A,(H/L) and obtaining a final image corrected for metallic artifacts. Following the completion of the algorithm, a DECT stoichiometric method was used to extract the relative electronic density (ρe) and effective atomic number (Z eff) at each voxel of the corrected scans. Tissue assignment could then be determined with these two newly acquired physical parameters. Each voxel was assigned the tissue bearing the closest resemblance in terms of ρe and Z eff, comparing with values from the ICRU 42 database. A MC study was then performed to compare the dosimetric impacts of alternative MAR algorithms. RESULTS: An improvement in tissue assignment was observed with the DECT MAR algorithm, compared to the single-energy computed tomography (SECT) approach. In a phantom study, tissue misassignment was found to reach 0.05% of voxels using the DECT approach, compared with 0.40% using the SECT method. Comparison of the DECT and SECT D 90 dose parameter (volume receiving 90% of the dose) indicated that D 90 could be underestimated by up to 2.3% using the SECT method. CONCLUSIONS: The DECT MAR approach is a simple alternative to reduce metallic artifacts found in LDRB patient scans. Images can be processed quickly and do not require the determination of x-ray spectra. Substantial information on density and atomic number can also be obtained. Furthermore, calcifications within the prostate are detected by the tissue assignment algorithm. This enables more accurate, patient-specific MC dose calculations.