2152 - Exploring the Clinical Landscape of Online Adaptive Radiotherapy in Taiwan: A 3-Year Retrospective Analysis of Case Distribution and Characteristics
Presenter(s)
T. C. Lin1,2, Y. R. Chang1, Y. Y. Yu1, Y. S. Chang3, A. C. Shiau1, and J. A. Liang1; 1Department of Radiation Oncology, China Medical University Hospital, Taichung City, Taiwan, 2Graduate Institute of Biomedical Sciences, China Medical University, Taichung City, Taiwan, 3China Medical University, Taichung City, Taiwan
Purpose/Objective(s): This retrospective study analyzes the clinical characteristics and treatment workflow of patients undergoing CBCT-based online adaptive radiotherapy (oART) at our institution, the only center in Taiwan offering this technology. Detailed process of each treatment fraction was recorded to assess the efficiency of our CBCT-based oART treatment workflow.
Materials/Methods: Each patient's treatment site and cancer type were recorded. Detailed time-motion studies were conducted using a stopwatch to record the duration of each treatment step. Also, the frequency and extent of target modifications were documented for each fraction. Target modifications were classified as 'no modification', 'minor modification' (<10 contours on axial views modified), and 'major modification' (>=10 contours on axial views modified).
Results: From July 2021 to December 2024, a total of 56 patients (1,154 fractions) had a comprehensive record of each treatment fraction. Adaptive plans were usually selected (85.8%, 990/1154; Scheduled plans: 14.2%, 164/1154). Adaptive plans were most frequently applied when the treatment site was the abdomen (100%, adaptive plans selected for all 37 fractions) and lung (97.1%, 33/34), followed by gynecologic cancer (88.9%, 80/90). Overall, time spent at each step of oART was the longest when the treatment site was the lung. Plan generation/selection (range: 172-450 seconds) and treatment (182-687 s) were the two most time-consuming steps. Target generation/preview (73-230 s), target editing (92-456 s), and plan generation/selection required physicians’ presence at the console. For target editing, GTV and CTV most frequently required modification when the treatment site was the lung, abdomen, and prostate (see Table).
Conclusion:
Despite the need for occasional target modifications, most of the time spent on the oART console was dedicated to plan generation and selection, rather than target editing. This indicates that while physicians can become proficient with the system relatively quickly, medical physicists and dosimetrists play a significant role in the overall treatment process. This study highlights the importance of optimizing the plan generation and selection process within the oART workflow. Further research and technological advancements may be necessary to streamline these steps and improve the overall efficiency. Abstract 2152 - Table 1: Distribution of treatment sites and extent of modification of GTV and CTV during target editing on oART console| Treatment site | Treatment site distribution | Count of modifiable targets (n) | GTV | CTV | ||||
| No modification | Major modification | Minor modification | No modification | Major modification | Minor modification | |||
| Abdomen | 12.5% | 39 | 28.2% | 15.4% | 5.1% | 23.1% | 0.0% | 28.2% |
| Gynecology | 5.4% | 162 | 13.6% | 0.0% | 3.1% | 67.9% | 1.2% | 14.2% |
| Head/Neck | 32.1% | 631 | 17.6% | 0.2% | 1.7% | 64.8% | 0.5% | 15.2% |
| Lung | 5.4% | 64 | 29.7% | 6.3% | 32.8% | 1.6% | 29.7% | 0.0% |
| Prostate | 37.5% | 442 | 26.0% | 0.7% | 3.2% | 36.4% | 3.2% | 30.5% |
| Bone metastases | 7.1% | 62 | 51.6% | 0.0% | 6.5% | 41.9% | 0.0% | 0.0% |