Dose Distribution Analysis in Stereotactic Body Radiotherapy Using Dynamic Conformal Multiple Arc Therapy
- Department of Radiology, Ofuna Chuo Hospital, Kanagawa (Japan)
- Department of Radiology, Tokyo Metropolitan Hiroo Hospital, Tokyo (Japan)
- Department of Radiology, Keio University, Tokyo (Japan)
Purpose: We have used dynamic conformal multiple arc therapy (DCMAT) for stereotactic body radiotherapy (SBRT) since 2001. We investigated the consistency of DCMAT for SBRT using dose-volume histogram analysis. Methods and Materials: A total of 50 patients with peripheral lung tumors underwent SBRT. The median tumor diameter was 2.4 cm (range, 0.9-5.9). Treatment planning was performed using a superposition algorithm. The prescribed 50 Gy dose was divided into five fractions. The prescribed dose was defined as 80% of the maximal dose in the planning target volume (PTV), and the leaf margins were modified to ensure the PTV was included in the 80% isodose surface. The dose-volume histogram analysis was used to assess the PTV and normal lung volume. Results: The median dose covering 95% of the PTV was 50.27 Gy (range, 46.14-52.67), essentially consistent with the prescribed dose. The median homogeneity and conformity index was 1.41 (range, 1.31-1.53) and 1.73 (range, 1.41-2.21), respectively. The median volume of lung receiving {>=}20 Gy (V{sub 20}) was 4.2% (range, 1.4-10.2%). A linear correlation was found between the tumor diameter and V{sub 20}, and an even stronger correlation was found between the PTV/(normal lung volume) and V{sub 20}. The estimated V{sub 20} was 7.1% (range, 3.9-10.4%) for a 5-cm-diameter tumor, assumed to be the maximal size limitation for SBRT. Conclusion: SBRT with DCMAT achieved high conformity and delivered adequate doses within the PTV. The median dose covering 95% of the PTV was consistent with the prescribed dose. V{sub 20} can be estimated using the tumor diameter and normal lung volume. DCMAT was thus both a feasible and a reproducible method of SBRT delivery.
- OSTI ID:
- 21276808
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 74, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2008.08.012; PII: S0360-3016(08)03293-8; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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