Effect of post-implant edema on prostate brachytherapy treatment margins
- Radiation Oncology, Arizona Oncology Services, Phoenix, AZ (United States)
- Department of Radiation Oncology, Puget Sound Health Care System, Department of Veterans Affairs, Seattle, WA (United States)
- Department of Radiation Oncology, University of Washington, Seattle, WA (United States)
- Schiffler Cancer Center, Wheeling, WV (United States)
- Department of Diagnostic Radiology, Puget Sound Health Care System, Department of Veterans Affairs, Seattle, WA (United States)
Purpose: To determine if postimplant prostate brachytherapy treatment margins calculated on Day 0 differ substantially from those calculated on Day 30. Methods: Thirty patients with 1997 American Joint Commission on Cancer clinical stage T1-T2 prostatic carcinoma underwent prostate brachytherapy with I-125 prescribed to 144 Gy. Treatment planning methods included using loose seeds in a modified peripheral loading pattern and treatment margins (TMs) of 5-8 mm. Postimplant plain radiographs, computed tomography scans, and magnetic resonance scans were obtained 1-4 hours after implantation (Day 0). A second set of imaging studies was obtained at 30 days after implantation (Day 30) and similarly analyzed. Treatment margins were measured as the radial distance in millimeters from the prostate edge to the 100% isodose line. The TMs were measured and tabulated at 90{sup o} intervals around the prostate periphery at 0.6-cm intervals. Each direction was averaged to obtain the mean anterior, posterior, left, and right margins. Results: The mean overall TM increased from 2.6 mm ({+-}2.3) on Day 0 to 3.5 mm ({+-}2.4) on Day 30. The mean anterior margin increased from 1.2 mm on Day 0 to 1.8 mm on Day 30. The posterior margin increased from 1.2 mm on Day 0 to 2.8 mm on Day 30. The lateral treatment margins increased most over time, with mean right treatment margin increasing from 3.9 mm on Day 0 to 4.7 mm on Day 30. Conclusion: Treatment margins appear to be durable in the postimplant period, with a clinically insignificant increase from Day 0 to Day 30.
- OSTI ID:
- 20788241
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 63, Issue 5; Other Information: DOI: 10.1016/j.ijrobp.2005.05.019; PII: S0360-3016(05)00838-2; Copyright (c) 2005 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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