Treatment planning issues related to prostate movement in response to differential filling of the rectum and bladder

• Published in: International journal of radiation oncology, biology, physics Vol. 20; no. 6; pp. 1317 - 1324
• Main Authors: Ten Haken, R.K., Forman, J.D., Heimburger, D.K., Gerhardsson, A., McShan, D.L., Perez-Tamayo, C., Schoeppel, S.L., Lichter, A.S.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.06.1991; Elsevier
• Subjects: Beam's-eye-view (BEV) planning; Biological and medical sciences; Computer Simulation; Computerized 3-D treatment planning; Conformal therapy; Diseases of the urinary system; Humans; Male; Medical sciences; Movement - physiology; Prostate - physiology; Prostate movement; Prostatic Neoplasms - physiopathology; Prostatic Neoplasms - radiotherapy; Radiotherapy Planning, Computer-Assisted; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Rectum - physiology; Urinary Bladder - physiology; Beam's-eye-view (BEV) planning; Prostate movement; Computerized 3-D treatment planning; Conformal therapy; Human; Urinary system disease; Carcinoma; Treatment; In situ; Irradiation; Technique; Malignant tumor; Radiotherapy; Prostate
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/0360-3016(91)90244-X

Conventional simulation for patients with localized prostatic carcinoma often includes opacification of the dose limiting adjacent normal tissues. However, CT-based treatment planning is performed with the bladder and the rectum naturally filled or emptied. These latter conditions more closely approximate those in place at treatment. Comparison of these CT-based treatment plans to simulator films taken with the rectum and bladder opacified yielded indirect evidence of movement of the prostate gland by 0.5 cm or more in 31 of 50 consecutive patients. The range of motion was 0 to 2 cm with an average of 0.5 cm (1.0 cm in the 31 patients). Six additional patients (five with local recurrence following I-125 seed implantation) were analyzed separately using CT scans. Registered CT images (3 mm slices) taken with the rectum and bladder full and/or empty provided direct evidence of prostate movement in 3 of the 6 patients. The dosimetric consequences of this movement are demonstrated using 3-dimensional dose distributions.