Radiation dermatitis caused by a bolus effect from an abdominal compression device.

Area of Science:

• Radiation Oncology
• Medical Physics
• Clinical Case Report

Background:

• American Association of Physicists in Medicine (AAPM) Task Group 176 reviewed dosimetric effects of immobilization devices in radiation therapy.
• Literature review noted a scarcity of clinical reports on skin toxicity from external devices.
• This study presents a clinical case of skin toxicity due to an abdominal compression device.

Observation:

• A 66-year-old male with esophageal adenocarcinoma developed grade 1 abdominal skin toxicity during neoadjuvant chemoradiation using an abdominal compression device.
• Radiation was delivered via volumetric modulated arc therapy (VMAT) with abdominal compression and image guidance.
• The patient developed dermatitis with two fractions remaining; the original plan did not contour the device.

Findings:

• Replanning with the abdominal compression device contoured revealed a bolus effect, increasing skin dose from 27Gy to 36Gy.
• Planned target volume (PTV) coverage decreased from 95.8% to 76.5% at 45Gy.
• An alternative plan with anterior avoidance maintained PTV coverage but increased lung dose.

Implications:

• External devices like abdominal compression devices can cause significant skin dose increases (bolus effect).
• Accurate contouring of devices or avoiding beam entrance is crucial for safe radiation delivery.
• Consideration of patient radiosensitivity (e.g., HIV-positive status) is important when using such devices.