A Pilot Clinical and Technical Validation of an Immersive Virtual Reality Platform for 3D Anatomical Modeling and Contouring in Support of Surgical and Radiation Oncology Treatment Planning.

The aim of this study was to validate a novel medical virtual reality (VR) platform used for medical image segmentation and contouring in radiation oncology and 3D anatomical modeling and simulation for planning medical interventions, including surgery. The first step of the validation was to verify quantitatively and qualitatively that the VR platform can produce substantially equivalent 3D anatomical models, image contours, and measurements to those generated with existing commercial platforms. To achieve this, a total of eight image sets and 18 structures were segmented using both VR and reference commercial platforms. The image sets were chosen to cover a broad range of scanner manufacturers, modalities, and voxel dimensions. The second step consisted of evaluating whether the VR platform could provide efficiency improvements for target delineation in radiation oncology planning. To assess this, the image sets for five pediatric patients with resected standard-risk medulloblastoma were used to contour target volumes in support of treatment planning of craniospinal irradiation, requiring complete inclusion of the entire cerebral-spinal volume. Structures generated in the VR and the commercial platforms were found to have a high degree of similarity, with dice similarity coefficient ranging from 0.963 to 0.985 for high-resolution images and 0.920 to 0.990 for lower resolution images. Volume, cross-sectional area, and length measurements were also found to be in agreement with reference values derived from a commercial system, with length measurements having a maximum difference of 0.22 mm, angle measurements having a maximum difference of 0.04°, and cross-sectional area measurements having a maximum difference of 0.16 mm2. The VR platform was also found to yield significant efficiency improvements, reducing the time required to delineate complex cranial and spinal target volumes by an average of 50% or 29 min.

Cranial Radiation Therapy as Salvage in the Treatment of Relapsed Primary CNS Lymphoma.

Primary central nervous system lymphoma (PCNSL) is a rare malignancy. Standard of care is upfront high-dose methotrexate (HD-MTX) chemotherapy, while cranial radiation is more commonly used in the salvage setting. In this retrospective study, we aimed to investigate the safety and efficacy of salvage cranial radiation in PCNSL. PCNSL patients who received upfront HD-MTX chemotherapy and salvage cranial radiation after treatment failure between 1995 and 2018 were selected. Radiological response to cranial radiation was assessed as per Response Assessment in Neuro-Oncology Criteria. Twenty one patients were selected (median age 59.9 years), with median follow-up of 19.9 months. Fourteen patients (66.7%) received a boost to the gross tumour volume (GTV). Four patients (19.0%) sustained grade ≥2 treatment-related neurotoxicity post-completion of cranial radiation. Of the 19 patients who had requisite MRI with gadolinium imaging available for Response Assessment in Neuro-Oncology (RANO) criteria assessment, 47.4% achieved complete response, 47.4% achieved partial response, and 5.3% of patients exhibited stable disease. Higher dose to the whole brain (>30 Gy) was associated with higher rate of complete response (63.6%) than lower dose (≤30 Gy, 37.5%), while boost dose to the gross disease was also associated with higher rate of complete response (61.5%) compared with no boost dose (33.3%). Median overall survival was 20.0 months. PCNSL patients who relapsed following upfront chemotherapy showed a high rate of response to salvage cranial radiation, especially in those receiving greater than 30 Gy to the whole brain and boost to gross disease.

The impact of COVID-19 workflow changes on radiation oncology incident reporting.

BACKGROUND: The Ottawa Hospital's Radiation Oncology program maintains the Incident Learning System (ILS)-a quality assurance program that consists of report submissions of errors and near misses arising from all major domains of radiation. In March 2020, the department adopted workflow changes to optimize patient and provider safety during the COVID-19 pandemic. PURPOSE: In this study, we analyzed the number and type of ILS submissions pre- and postpandemic precautions to assess the impact of COVID-19-related workflow changes. METHODS: ILS data was collected over six one-year time periods between March 2016 and March 2021. For all time periods, the number of ILS submissions were counted. Each ILS submission was analyzed for the specific treatment domain from which it arose and its root cause, explaining the impetus for the error or near miss. RESULTS: Since the onset of COVID-19-related workflow changes, the total number of ILS submissions have reduced by approximately 25%. Similarly, there were 30% fewer ILS submissions per number of treatment courses compared to prepandemic data. There was also an increase in the proportion of "treatment planning" ILS submissions and a 50% reduction in the proportion of "decision to treat" ILS submissions compared to previous years. Root cause analysis revealed there were more incidents attributable to "poor, incomplete, or unclear documentation" during the pandemic year. CONCLUSIONS: COVID-19 workflow changes were associated with fewer ILS submissions, but a relative increase in submissions stemming from poor documentation and communication. It is imperative to analyze ILS submission data, particularly in a changing work environment, as it highlights the potential and realized mistakes that impact patient and staff safety.

The History and Future of Ablative Neurosurgery for Major Depressive Disorder.

BACKGROUND: There is an urgent need to develop safe and effective treatments for patients with treatment-resistant depression (TRD). Several neurosurgical procedures have been developed to treat the dysfunctional brain circuits implicated in major depression. OBJECTIVES: This review describes the most common ablative procedures used to treat major depressive disorder: anterior cingulotomy, subcaudate tractotomy, limbic leucotomy, and anterior capsulotomy. The efficacy and safety of each are discussed and compared with other current and emerging modalities, including deep brain stimulation (DBS) and MR-guided focused ultrasound (MRgFUS). METHODS: The PubMed and MEDLINE electronic databases were used in this study, through July 2016. Keywords, including "treatment resistant depression," and "ablative neurosurgery," etc. were used to generate reference hits. RESULTS: Approximately a third to half of patients who underwent ablative procedures achieved a treatment response and/or remission. The efficacy and safety profiles corresponding to both ablative procedures and DBS were very similar. CONCLUSIONS: The longitudinal experience with ablative procedures shows that there remains an important role for accurate, discrete lesions in disrupting affective circuitry in the treatment of TRD. New modalities, such as MRgFUS, have the potential to further improve the accuracy of ablative procedures, while enhancing safety by obviating the need for open brain surgery.

Deep brain stimulation of the subcallosal cingulate for treatment-refractory anorexia nervosa: 1 year follow-up of an open-label trial.

BACKGROUND: Anorexia nervosa is a life-threatening illness. Brain circuits believed to drive anorexia nervosa symptoms can be accessed with surgical techniques such as deep brain stimulation (DBS). Initial results suggest that DBS of the subcallosal cingulate is safe and associated with improvements in mood and anxiety. Here, we investigated the safety, clinical, and neuroimaging outcomes of DBS of the subcallosal cingulate in a group of patients during 12 months of active stimulation. METHODS: We did this prospective open-label trial at the Department of Surgery of the University of Toronto (Toronto, ON, Canada). Patients were eligible to participate if they were aged 20-60 years and had a diagnosis of anorexia nervosa (restricting or binge-purging subtype) and a demonstrated history of chronicity or treatment resistance. Following a period of medical stabilisation, patients underwent surgery for DBS and received open-label continuous stimulation for the entire 1 year study duration. The primary outcome was safety and acceptability of the procedure. The secondary outcomes were body-mass index (BMI), mood, anxiety, affective regulation, and anorexia nervosa-specific behaviours at 12 months after surgery, as well as changes in neural circuitry (measured with PET imaging of cerebral glucose metabolism at baseline and at 6 and 12 months after surgery). This trial was registered with ClinicalTrials.gov, number NCT01476540. FINDINGS: 16 patients with treatment-refractory anorexia nervosa were enrolled between September, 2011, and January, 2014, and underwent DBS of the subcallosal cingulate between November, 2011, and April, 2014. Patients had a mean age of 34 years (SD 8) and average illness duration of 18 years (SD 6). Two patients requested that their devices be removed or deactivated during the study, although their reasons for doing so were poorly defined. The most common adverse event was pain related to surgical incision or positioning that required oral analgesics for longer than 3-4 days after surgery (five [31%] of 16 patients). Seven (44%) of 16 patients had serious adverse events, most of which were related to the underlying illness, including electrolyte disturbances. Average BMI at surgery was 13·83 (SD 1·49) and 14 (88%) of the 16 patients had comorbid mood disorders, anxiety disorders, or both. Mean BMI after 12 months of stimulation was 17·34 (SD 3·40; p=0·0009 vs baseline). DBS was associated with significant improvements in measures of depression (mean Hamilton Depression Rating Scale scores 19·40 [SD 6·76] at baseline vs 8·79 [7·64] at 12 months; p=0·00015), anxiety (mean Beck Anxiety Inventory score 38·00 [15·55] vs 27·14 [18·39]; p=0·035), and affective regulation (mean Dysfunction in Emotional Regulation Scale score 131·80 [22·04] vs 104·36 [31·27]; p=0·019). We detected significant changes in cerebral glucose metabolism in key anorexia nervosa-related structures at both 6 months and 12 months of ongoing brain stimulation. INTERPRETATION: In patients with chronic treatment-refractory anorexia nervosa, DBS is well tolerated and is associated with significant and sustained improvements in affective symptoms, BMI, and changes in neural circuitry at 12 months after surgery. FUNDING: Klarman Family Foundation Grants Program in Eating Disorders Research and Canadian Institutes of Health Research.