A technique for total skin electron therapy (TSET) of an anesthetized pediatric patient

Abstract

PurposeTotal skin electron therapy (TSET) is a technique to treat cutaneous lymphomas. While TSET is rarely required in pediatric patients, it poses particular problems for the delivery. It was the aim of the present work to develop a method to deliver TSET to young children requiring anesthetics during treatment.MethodsA customized cradle with a thin window base and Poly(methyl‐methacrylate) (PMMA) frame was built and the patient was treated in supine position. Two times six fields of 6 MeV electrons spaced by 60° gantry angles were used without electron applicator and a field size of 36 × 36 cm2. The two sets of six fields were matched at approximately 65% surface dose by rotating the patient around an axis 30 cm distance from beam central axis, effectively displacing the two sets of fields in sup/inf direction by 60 cm. Electron energy was degraded using a 12 mm PMMA block on the gantry. Focus to skin distance was maximized by displacing the patient in opposite direction of the beam resulting in a different couch position for each field.ResultsA 2‐yr‐old patient was treated in 12 fractions of 1.5 Gy over 2.4 weeks. Dose to skin was verified daily using thermoluminescence dosimetry and/or radiochromic film. The treatment parameters were adjusted slightly based on in vivo dosimetry resulting in a dose distribution for most of the treatment volume within ±20% of the prescribed dose. Six areas were boosted using conventional electron therapy.Conclusion TSET can be delivered to pediatric patients using a customized couch top on a conventional linear accelerator.

In vivo monitoring of total skin electron dose using optically stimulated luminescence dosimeters

“…13 TLD measurements have also been used to investigate newer TSET delivery techniques, such as the use of single electron fields (rather than paired electron fields), 12 the use of a platform to rotate the patient during beam delivery, 6,15 and the treatment of anaesthetised paediatric patients. 16 Guidi et al's review of the literature on in vivo dosimetry for TSET treatments also referred to several studies that used MOSFET dosimeters and radiochromic film, 10 as well as one study that reported diode measurements performed on 360 patients treated using electron beam radiation delivered to lesions at various anatomical sites. 17 The use of glass beads as alternative TLDs has also been reported, specifically for TSET dosimetry.…”