Related Experiment Videos
In vivo isocenter dose in two hip prosthesis patients
W D Burleson1, C D Stutzman, J A Stitt
1Department of Radiology, University of Colorado, Denver 80262.
Summary
Hip prostheses can alter radiation doses in the pelvis. Dosimetry showed a 13% dose decrease with bilateral prostheses using conventional four-field beams, suggesting technique modifications may be needed.
Area of Science:
- Radiation Oncology
- Medical Physics
- Biomedical Engineering
Background:
- Hip prostheses are common in patients requiring pelvic radiotherapy.
- Metal implants can cause significant artifacts and dose perturbations in radiation treatment planning.
- Understanding these effects is crucial for accurate dose delivery.
Purpose of the Study:
- To investigate the impact of hip prostheses on radiation dose distribution in the prostatic urethra.
- To compare dose variations between conventional and modified beam geometries.
- To assess the influence of unilateral versus bilateral prostheses.
Main Methods:
- Thermoluminescent dosimetry (TLD) measurements were performed in the prostatic urethra.
- Measurements were conducted on two patients with varying hip prosthesis configurations (unilateral and bilateral).
- Exposures utilized 24 MV photon portal beams with different field geometries.
Main Results:
- A notable decrease in absorbed dose was observed with bilateral hip prostheses.
- The dose reduction was approximately 13% specifically for conventional four-field beam geometry.
- Unilateral prostheses and oblique four-field beam geometry showed less significant dose perturbations.
Conclusions:
- Hip prostheses can lead to significant irradiation dose inhomogeneities in pelvic radiotherapy.
- Conventional four-field beam techniques are particularly susceptible to dose reduction with bilateral prostheses.
- Modifications to beam techniques may be necessary to ensure adequate dose coverage in patients with hip prostheses.