Abstract
Prostate movement is an important factor for consideration in radiotherapy planning, especially with the advent of three-dimensional conformal radiotherapy. To date, the reports on prostate movement have been limited by small cohorts of patients or the technique used to detect small movements. Two sets of orthogonal films of 75 patients therapeutically implanted with gold seeds were superimposed, and all bony landmarks were aligned. Any discrepancies in the seeds' positions were recorded as prostate movement. Bladder and rectal volumes and prostate size were determined from the orthogonal films or treatment-planning computed tomography scans. Movement occurred as a translation and rotation (axis through the urogenital diaphragm) imparting more movement at the base of the prostate. Mean translations were 2.3 mm in the anteroposterior (AP) dimension vs 0.3 mm laterally and 1.6 mm superior-inferiorly. Average rotations were 3.8° and 0.4° in AP and lateral dimensions, respectively. Movement correlated with rectal changes (P=.04) and bladder changes (P=.06) but not with prostate size. In conclusion, lateral movement is extremely limited. The AP movement can become clinically significant in conformal treatment plans, especially near the more mobile prostate base. Prostate immobilization during three-dimensional conformal radiotherapy (eg, intensity-modulated radiotherapy) is recommended.
Original language | English (US) |
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Pages (from-to) | 199-206 |
Number of pages | 8 |
Journal | Journal of Brachytherapy International |
Volume | 16 |
Issue number | 3 |
State | Published - 2000 |
Keywords
- Brachytherapy
- Prostate cancer
- Prostate movement
ASJC Scopus subject areas
- Cancer Research
- Radiology Nuclear Medicine and imaging