Back to Search
Start Over
Objective Assessment of the Effects of Tumor Motion in Radiation Therapy
- Source :
- Med Phys
- Publication Year :
- 2019
-
Abstract
- PURPOSE: Internal organ motion reduces the accuracy and efficacy of radiation therapy. However, there is a lack of tools to objectively (based on a medical or scientific task) assess the dosimetric consequences of motion, especially on an individual basis. We propose to use therapy operating characteristic (TOC) analysis to quantify the effects of motion on treatment efficacy for individual patients. We demonstrate the application of this tool with pancreatic stereotactic body radiation therapy (SBRT) clinical data and explore the origin of motion sensitivity. METHODS: The technique is described as follows. (1) Use tumor-motion data measured from patients to calculate the motion-convolved dose of the gross tumor volume (GTV) and the organs at risk (OARs). (2) Calculate tumor control probability (TCP) and normal tissue complication probability (NTCP) from the motion-convolved dose volume histograms. (3) Construct TOC curves from TCP and NTCP models. (4) Calculate the area under the TOC curve (AUTOC) and use it as a figure of merit for treatment efficacy. We used tumor motion data measured from patients to calculate the relation between AUTOC and motion magnitude for 25 pancreatic SBRT treatment plans. Furthermore, to explore the driving factor of motion sensitivity of a given plan, we compared the dose distribution of motion-sensitive plans and motion-robust plans and studied the dependence of motion sensitivity to motion directions. RESULTS: Our technique is able to recognize treatment plans that are sensitive to motion. Under the presence of motion, the treatment efficacy of some plans changes from providing high tumor control and low risks of complications to providing no tumor control and high risks of side effects. Several treatment plans experience falloffs in AUTOC at a smaller magnitude of motion than other plans. In our dataset, a potential indicator of a motion-sensitive treatment plan is that the duodenum is in close proximity to the tumor in the SI direction. CONCLUSIONS: The TOC framework can serve as a tool to quantify the effects of internal organ motion in radiation therapy. With pancreatic SBRT clinical data, we applied this tool to study the change in treatment efficacy induced by motion for individual treatment plans. This framework could potentially be used clinically to understand the effects of motion in an individual patient and to design a patient-specific motion management plan. This framework could also be used in research to evaluate different components of the treatment process, such as motion-management techniques, treatment-planning algorithms, treatment margins, etc.
- Subjects :
- medicine.medical_specialty
business.industry
medicine.medical_treatment
Movement
Radiotherapy Planning, Computer-Assisted
Cancer
Radiotherapy Dosage
General Medicine
medicine.disease
Radiosurgery
Treatment efficacy
Article
030218 nuclear medicine & medical imaging
Objective assessment
Radiation therapy
Pancreatic Neoplasms
03 medical and health sciences
0302 clinical medicine
030220 oncology & carcinogenesis
medicine
Humans
Medical physics
business
Tumor motion
Medical systems
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Med Phys
- Accession number :
- edsair.doi.dedup.....71c85ea9c96524edeccf6af81a983946