Practical Radiation Oncology最新文献

Purpose: Spinal stereotactic body radiation therapy (SBRT) has become the standard of care in management of patients with limited sites of metastatic disease, radio-resistant histologies, painful vertebral metastases with long life expectancy and cases of reirradiation. Our case-based guidelines aim to assist radiation oncologists in the appropriate utilization of SBRT for common, yet challenging, cases of spinal metastases.

Materials and methods: Cases were selected to include scenarios of large volume sacral disease with nerve entrapment, medically inoperable disease abutting the thecal sac, and local failure after prior SBRT. Relevant literature was reviewed, and areas requiring further investigation were discussed to offer a framework for evidence-based clinical practice.

Results: Spinal SBRT can be effectively delivered in challenging cases following multidisciplinary discussion by utilizing a methodical approach to patient selection, appropriate dose selection, and adherence to evidence-based dose constraints.

Conclusions: The Radiosurgery Society's case-based practice review offers guidance to practicing physicians treating technically challenging SBRT candidate patients with spinal metastases.

Purpose: The current commonly-used metrics for evaluating the quality of auto-segmented contours have limitations and do not always reflect the clinical usefulness of the contours. This work aims to develop a novel contour quality classification (CQC) method by combining multiple quantitative metrics for clinical usability-oriented contour quality evaluation for deep learning-based auto-segmentation (DLAS).

Methods: The CQC was designed to categorize contours on slices as acceptable, minor edit, or major edit based on the expected editing effort/time with supervised ensemble tree classification models using seven quantitative metrics. Organ-specific models were trained for five abdominal organs (pancreas, duodenum, stomach, small and large-bowels) using 50 MRI datasets. Twenty additional MRI and nine CT datasets were employed for testing. Inter-observer variation (IOV) was assessed among six observers and consensus labels were established through majority vote for evaluation. The CQC was also compared with a threshold-based baseline approach.

Results: For the five organs, the average AUC was 0.982±0.01 and 0.979±0.01, the mean-accuracy was 95.8±1.7% and 94.3±2.1%, and the mean risk-rate was 0.8±0.4% and 0.7±0.5% for MRI and CT testing dataset, respectively. The CQC results closely matched the IOV results (mean-accuracy of 94.2±0.8% and 94.8±1.7%) and were significantly higher than those obtained using the threshold-based method (mean-accuracy of 80.0±4.7%, 83.8±5.2%, and 77.3±6.6% using one, two, and three metrics).

Conclusion: The CQC models demonstrated high performance in classifying the quality of contour slices. This method can address the limitations of existing metrics and offers an intuitive and comprehensive solution for clinically oriented evaluation and comparison of DLAS systems.

Background: The phase III Veterans Affairs Lung cancer surgery Or stereotactic Radiotherapy (VALOR) study implemented centralized quality assurance (QA) to mitigate risks of protocol deviations. This report summarizes quality and compliance for the first 100 participants treated with SBRT in this study.

Methods: A centralized QA program was developed to credential and monitor study sites to ensure standard-of-care lung stereotactic body radiation therapy (SBRT) treatments are delivered to participants. Requirements were adapted from protocols established by the National Cancer Institute's Image and Radiation Oncology Core, which provides oversight for clinical trials sponsored by the NCI's National Clinical Trials Network.

Results: The first 100 lung SBRT treatment plans were reviewed from April 2017 to October 2022. Tumor contours were appropriate in all submissions. PTV expansions were less than the minimum 5 mm requirement in 2% of cases. Critical organ-at-risk (OAR) structures were contoured accurately for the proximal bronchial tree, trachea, esophagus, spinal cord, and brachial plexus in 75%, 92%, 100%, 100%, and 95% of cases. Prescriptions were appropriate in 98% of cases; two central tumors were treated using a peripheral tumor dose prescription while meeting OAR constraints. PTV V100% values were above the protocol-defined minimum of 94% in all but one submission. The median Dmax within the PTV was 125.4% (105.8% - 149.0%, standard deviation ±8.7%). High-dose conformality (<1.2) and intermediate-dose compactness (R50% and D2cm) indices were acceptable or deviation acceptable in 100% and 94% of cases, respectively.

Conclusions: The first 100 participants randomized to SBRT in this study were appropriately treated without safety concerns. A response to the incorrect prescriptions led to preventative measures without further recurrences. The program was developed in a healthcare system without prior experience with a centralized RT QA program and may serve as a reference for other institutions.