TITLE:
Dual-Fields Rotational Total Skin Electron Therapy: Investigation and Implementation
AUTHORS:
M. Ming Xu, Iris Rusu, Richard P. Garza
KEYWORDS:
Total Skin, Electron Therapy, Stanford 6 Field, McGill Rotation Therapy, In-Vivo Dosimetry
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.13 No.1,
February
18,
2024
ABSTRACT: Purpose: To present a protocol of a dual-field rotational
(DFR) total skin electron therapy (TSET) and to provide an assessment of
clinical implementation, dosimetry properties, and skin dose evaluation. Methods
and Materials: The DFR-TSET combined the Stanford 6-field and McGill
rotational methods. Dual 6 MeV electron beams in high dose total skin electron
mode were used for DFR-TSET on a commercial linac. Beam profiles and dosimetric
properties were measured using solid phantoms. The dose rate at expanded
source-to-surface distance (SSD) was a combination of static rate and
rotational rate. In vivo dosimetry of patient skin was performed on patients’ skin using film, metal oxide semiconductor
field-effect transistors (MOSFET), and optically stimulated luminescent dosimeters (OSLD). Results: Dual field
rotational total skin electron therapy exhibited good (≤±10%) uniformity in the beam profiles in the
vertical direction at an extended SSD of 332 cm with a gantry angulation of ±20˚ deviated from the horizontal direction. In-vivo measurements confirmed acceptable uniformity of the patients’ total body
surfaces and revealed anatomically self-blocked or shielded areas where underdosing
occurred. Conclusions: The clinical implementation of DFR-TSET
effectively utilizes the special mode on a linac. This technique provides short
beam-on times, uniform dose distribution, large treatment field, and reduced
dose of x-ray contamination to the patients. In-vivo measurements indicate satisfactory delivery and dose
uniformity of the prescribed dose. Electron boost fields are recommended at
normal SSDs to address underdosed areas.