1Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO 63110.
This study examined how breast prostheses affect radiation therapy and whether radiation affects the implants themselves. Researchers tested four different types of implants using dosimeters and a phantom model. They found that implants do not change how radiation is delivered to the breast tissue. However, radiation exposure caused physical changes in the implants, including color shifts and reduced formability, especially in one type of implant. These findings suggest that while implants do not interfere with radiation dose distribution, their own structural changes may need to be considered in treatment planning.
You might also read
Articles linked to this work by shared authors, journal, and citation graph.
Area of Science:
Background:
Radiation therapy is a common treatment for breast cancer, but the presence of implants can alter dose distribution. Prior research has shown that implants may influence photon beam interactions. However, the specific effects of different implant materials remain unclear. This gap motivated a study to assess dosimetric changes caused by prostheses. Existing knowledge suggests implants may perturb radiation fields. Yet, no prior work had resolved whether all implants behave similarly. The study aimed to compare various implant types. It also sought to evaluate physical changes in implants after irradiation.
Purpose Of The Study:
This study aimed to quantify how breast prostheses affect photon dose distributions. It also investigated whether implants themselves undergo physical changes during radiation therapy. The specific problem addressed is the lack of data on how different implant materials interact with radiation. The motivation stems from clinical concerns about dose accuracy in patients with implants. The goal was to determine if implants alter dose delivery or are altered by radiation. The study focused on commercial prostheses with varying filler and shell materials. It sought to compare dosimetric effects across implant types. The results could inform treatment planning for patients with implants.
According to the authors, prostheses do not significantly alter photon beam distribution during radiation therapy.
The study tested four commercial prostheses with varying gel fillers and shell materials, including silicon and polyurethane.
The researchers selected 50 Gy to simulate typical radiation therapy doses and assess implant stability under clinical conditions.
Tonometry testing showed the bio-oncotic gel implant became significantly less formable after radiation exposure.
Main Methods:
The study used a thin window parallel-plate chamber and thermoluminescent dosimeters to measure dose changes. Four commercial prostheses were compared with a mammographic phantom. The implants included different gel fillers and shell materials. Tonometry testing assessed physical changes in the implants after irradiation. Color changes were also recorded as a qualitative indicator of damage. The implants were exposed to 50 Gy of radiation. Post-irradiation assessments occurred immediately and six weeks later. The experimental setup allowed for precise dosimetric comparisons.
Main Results:
Ion chamber results showed no significant alteration of depth doses away from the implant. Minor interface perturbations were observed for all implants. The study found that prostheses do not affect photon beam distribution. However, radiation affected the implants themselves. Color changes occurred in all implants after 50 Gy exposure. The bio-oncotic gel implant showed significant formability loss after irradiation. This effect worsened six weeks post-irradiation. The tri-glyceride implant also exhibited color change but no formability loss.
Conclusions:
The data indicates that prostheses do not alter photon beam distribution during radiation therapy. However, radiation exposure causes physical changes in the implants themselves. Color changes were observed in all tested implants after 50 Gy. The bio-oncotic gel implant became less formable after irradiation. This change was more pronounced six weeks later. The study confirms implants do not affect dose delivery. But radiation may impact implant integrity over time. These findings suggest implants should be considered in treatment planning.
All implants exhibited color change after 50 Gy exposure, with the bio-oncotic gel showing the most noticeable shift.
The authors suggest implants should be considered in treatment planning due to their potential long-term physical changes.