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Title: Cancer risk estimates from radiation therapy for heterotopic ossification prophylaxis after total hip arthroplasty

Purpose: Heterotopic ossification (HO) is a frequent complication following total hip arthroplasty. This study was conducted to calculate the radiation dose to organs-at-risk and estimate the probability of cancer induction from radiotherapy for HO prophylaxis.Methods: Hip irradiation for HO with a 6 MV photon beam was simulated with the aid of a Monte Carlo model. A realistic humanoid phantom representing an average adult patient was implemented in Monte Carlo environment for dosimetric calculations. The average out-of-field radiation dose to stomach, liver, lung, prostate, bladder, thyroid, breast, uterus, and ovary was calculated. The organ-equivalent-dose to colon, that was partly included within the treatment field, was also determined. Organ dose calculations were carried out using three different field sizes. The dependence of organ doses upon the block insertion into primary beam for shielding colon and prosthesis was investigated. The lifetime attributable risk for cancer development was estimated using organ, age, and gender-specific risk coefficients.Results: For a typical target dose of 7 Gy, organ doses varied from 1.0 to 741.1 mGy by the field dimensions and organ location relative to the field edge. Blocked field irradiations resulted in a dose range of 1.4–146.3 mGy. The most probable detriment from open field treatment ofmore » male patients was colon cancer with a high risk of 564.3 × 10{sup −5} to 837.4 × 10{sup −5} depending upon the organ dose magnitude and the patient's age. The corresponding colon cancer risk for female patients was (372.2–541.0) × 10{sup −5}. The probability of bladder cancer development was more than 113.7 × 10{sup −5} and 110.3 × 10{sup −5} for males and females, respectively. The cancer risk range to other individual organs was reduced to (0.003–68.5) × 10{sup −5}.Conclusions: The risk for cancer induction from radiation therapy for HO prophylaxis after total hip arthroplasty varies considerably by the treatment parameters, organ site in respect to treatment volume and patient's gender and age. The presented risk estimates may be useful in the follow-up studies of irradiated patients.« less
Authors:
; ;  [1] ;  [2]
  1. Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, 71003 Iraklion, Crete (Greece)
  2. Department of Radiotherapy and Oncology, University Hospital of Iraklion, 71110 Iraklion, Crete (Greece)
Publication Date:
OSTI Identifier:
22220403
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 40; Journal Issue: 10; Other Information: (c) 2013 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 61 RADIATION PROTECTION AND DOSIMETRY; BLADDER; DOSE EQUIVALENTS; DOSIMETRY; HEALTH HAZARDS; LARGE INTESTINE; LIVER; LUNGS; MAMMARY GLANDS; MONTE CARLO METHOD; NEOPLASMS; OVARIES; PATIENTS; PHANTOMS; PHOTON BEAMS; PREVENTIVE MEDICINE; PROSTATE; RADIATION DOSES; RADIOTHERAPY; STOMACH; THYROID; UTERUS