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Computerized tomographic simulation compared with clinical mark-up in palliative radiotherapy: a prospective study
Peiman Haddad1, Fred Cheung, Gregory Pond
1Palliative Radiation Oncology Program, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada.
Summary
Clinical mark-up (CM) for palliative radiation of chest wall metastases resulted in significant clinical tumor volume (CTV) under-coverage. Computed tomographic (CT) planning offers improved accuracy for radiation delivery to chest wall metastases.
Area of Science:
- Radiation Oncology
- Medical Imaging
- Oncology
Background:
- Palliative radiation therapy is crucial for managing chest wall metastases.
- Accurate targeting of the clinical tumor volume (CTV) is essential for effective treatment and minimizing toxicity.
- Traditional clinical mark-up (CM) methods may lack precision in defining radiation fields.
Purpose of the Study:
- To compare the accuracy of computed tomographic (CT) planning versus clinical mark-up (CM) for palliative radiation of chest wall metastases.
- To quantify the under-coverage of CTV using CM compared to CT-based planning.
Main Methods:
- Retrospective analysis of 21 palliative radiation treatments for chest wall bone metastases.
- Acquisition of two planning CT scans: one with CM and one without, for 19 comparable cases.
- Fusion of CT scans to evaluate CTV coverage by the CM 80% isodose and assess normal tissue dose distribution.
Main Results:
- Clinical mark-up (CM) resulted in a mean CTV under-coverage of 36% for chest wall metastases.
- Over half of the cases (58%) treated with CM showed >20% CTV under-coverage.
- CT planning led to a significant increase in the mean volume of normal tissues receiving >=80% of the dose (9.3% vs 5.4% with CM, p=0.017), indicating potentially better sparing.
Conclusions:
- Computed tomographic (CT) planning significantly improves the accuracy of radiation delivery for chest wall metastases compared to clinical mark-up (CM).
- CM techniques lead to substantial under-coverage of the clinical tumor volume (CTV), potentially compromising treatment efficacy.
- CT-based planning allows for more precise definition of radiation fields, potentially altering treatment techniques and improving normal tissue sparing.