Risks of secondary malignancies with heterotopic bone radiation therapy for patients younger than 40 years

Journal Article · Sat Oct 01 04:00:00 EDT 2016 · Medical Dosimetry

DOI:https://doi.org/10.1016/J.MEDDOS.2016.02.001· OSTI ID:22685149

DesRosiers, Colleen ^[1]; McMullen, Kevin ^[2]

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1. Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States)
2. Department of Radiation Oncology, IU Health Methodist Hospital, Indianapolis, IN (United States)

Heterotopic ossification (HO) of the bone is defined as a benign condition in which abnormal bone formation occurs in soft tissue. One of the most common prophylactic treatments for HO is radiation therapy (RT). This study retrospectively reviewed 20 patients younger than the age of 40 who received radiation to prevent HO in a single fraction of 7 Gray. The purpose of this study is to assess the risk of a second malignancy in these patients by recreating their treatment fields and contouring organs at risk to estimate the radiation dose absorbed by normal tissues outside the radiation treatment field. Diagnostic computed tomography (CT) scans for each patient were used to recreate treatment fields and to calculate dose to structures of interest. The distance from the field edge to each structure and its depth was recorded. Dose measurements in a water phantom were performed for the range of depths, distances, and field sizes used in the actual treatment plans. Computer-generated doses were compared to estimates based on measurement. The structure dose recorded was the higher dose generated between the 2 methods. Scatter dose was recorded to the rectum, bladder, sigmoid colon, small bowel, ovaries and utero-cervix in female patients, and prostate and gonads in male patients. In some patients, there is considerable dose received by certain organs from scatter because of their proximity to the radiation field. The average dose to the ovarian region was 4.125 Gy with a range of 1.085 to 6.228 Gy. The risk estimate for these patients ranged from 0.16% to 0.93%. The average total lifetime risk estimate for the bladder in all patients is 0.22% and the average total lifetime risk estimate for the remainder organs in all patients is 1.25%. In conclusions, proper shielding created from multileaf collimators (MLCs), blocks, and shields should always be used when possible.

• OSTI ID: 22685149
• Journal Information: Medical Dosimetry, Journal Name: Medical Dosimetry Journal Issue: 3 Vol. 41; ISSN 0958-3947
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMAL TISSUES
BLADDER
COLLIMATORS
COMPUTERIZED TOMOGRAPHY
COMPUTERS
FEMALES
HAZARDS
IMAGE PROCESSING
LIFETIME
MALES
NEOPLASMS
OVARIES
PATIENTS
PHANTOMS
PROSTATE
RADIATION DOSE UNITS
RADIATION DOSES
RADIOTHERAPY
RECTUM
REVIEWS
SHIELDING
SHIELDS
SIDE EFFECTS
SKELETON