A technique for pediatric total skin electron irradiation

Area of Science:

• Medical Physics
• Radiation Oncology
• Pediatric Oncology

Background:

• Total skin electron irradiation (TSEI) is a radiotherapy technique primarily used for adult mycosis fungoides.
• Leukemia cutis isolated to the skin in infants is a rare condition necessitating TSEI.
• This study details the adaptation of TSEI for pediatric patients.

Purpose of the Study:

• To describe the commissioning and quality assurance (QA) for a modified TSEI technique in pediatric patients.
• To ensure accurate and safe radiation delivery for infants with skin-localized leukemia.
• To present the successful clinical implementation of pediatric TSEI.

Main Methods:

• Commissioning involved absolute calibration, dosimetric parameter measurement, and phantom verification using film and OSL dosimeters.
• A modified Stanford technique with a rotating harness system was developed for positioning sedated pediatric patients.
• A comprehensive pediatric TSEI QA program was established, including daily checks and in-vivo dosimetry.

Main Results:

• Dosimetric evaluation in a pediatric phantom confirmed a 2 cm electron penetration depth with surface maximum dose.
• The skin to calibration point dose factor (B-factor) was found to be larger in pediatric TSEI compared to adults.
• In-vivo dosimetry in two infants demonstrated treatment delivery within ±10% of the prescribed dose.

Conclusions:

• Adapting TSEI for pediatric leukemia cutis is feasible using a modified total body irradiation stand.
• The developed commissioning and QA protocols support the clinical implementation of pediatric TSEI.
• Successful treatment of two pediatric patients validates the modified TSEI technique.