| Autor: |
Kim, Sun I., Suh, Tae Suk, Magjarevic, R., Nagel, J. H., Ricky Ming Chun Chau, Leung, S. F., Kam, K. M., Cheung, K. Y., Kwan, W. H., Yu, K. H., Chiu, K. W., Chan, T C. |
| Zdroj: |
World Congress on Medical Physics & Biomedical Engineering 2006; 2007, p1965-1968, 4p |
| Abstrakt: |
Background & Purpose: It is time consuming to contour numerous structures on CT images during intensity-modulated radiation therapy (IMRT) planning for nasopharyngeal carcinoma (NPC). The present study compares the dosimetry of using ‘interpolated' contours and ‘real' contours in advanced-stage NPC. Methods & Materials: Twenty NPC patients with T3-4 tumors were selected and contours of targets and OARs were delineated on consecutive CT images. For each patient, a reference (REF) IMRT plan was generated based on these ‘real' contours. An investigative (INV) IMRT plan was generated with the same planning protocol but based on ‘interpolated' contours that were reformed after deleting the contours on alternate slices and replacing the deleted contours by the interpolated contours of the adjacent slices. The dose-endpoints of targets and OARs between two plans were compared. Results: For both the gross tumor volume (GTV) and planning target volume (PTV), all cases in both plans achieved 95% volume receiving the prescribed dose, and less than 1% volume receiving <93% dose, except for the PTV in the INV plan for 1 case. For the brainstem, the mean maximum dose (Dmax) (53.6Gy vs 53.8Gy, p=0.443) was not significantly increased in the INV plans. For the spinal cord, the Dmax (43.5Gy vs 44.0Gy, p=0.026) was significantly increased in the INV plan and the Dmax exceed 45Gy in 5/20 cases in both plans. There was no significant difference between the two plans in the mean dose of the parallel-sensitive organs. Conclusions: The use of interpolated contours resulted in a modest reduction in the minimum dose of the targets and an increase in the maximum dose of the brainstem and spinal cord, however, the small magnitude of difference is unlikely to be clinically significant. Despite the limitation of small sample size, further investigation of this timing-saving technique is justified.. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
