In this work we first analyzed the reliability of materials supplied by the main firms, which must be considered when defining the lesion and planning target volume. The coordinates of specific target landmarks, i.e., bone, calcium deposition or catheters, on baseline CT scans were compared with those measured on control scans. Since the PLATO-SRS system yields 3 coordinates for each target, the final error is calculated by the evaluation of the shift of the different coordinates. The mean error reported for the first material (ORFIT) was 5 mm (13/23 patients). This margin of error is too high and was considered unacceptable; a second material was then tested. The latter, which is not recyclable and softens at higher temperatures, exhibited a mean error of 2.5 mm (10/23 patients), which allows daily repositioning of greater reliability. Treatment was repeated in 4/20 arcs in all, which number depended mainly on fraction size. Correct lesion location and patient positioning were allowed by laser landmarks on the mask made directly on the treatment couch. The laser too was checked before each treatment session, i.e., preferentially at the end of an ordinary working day.
|Translated title of the contribution||Advantages of a system of positioning and localization made of thermo-conformable materials for irradiation of cervicofacial and encephalic lesions treated with stereotactic fractionated radiation|
|Number of pages||3|
|Publication status||Published - Mar 1995|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging