ESTRO 2024 - Abstract Book

S3341

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Figure 1 shows the mean doses for all the patients at each measurement point relative to the prescribed dose. For all the points, except for foot and hand, difference between prescribed dose and the mean measured dose remains below ±11%. Locations such as the forehead, between clavicles, navel, left lateral trunk, left quadriceps, lumbar and right triceps, show smaller differences of ±3%. The hand consistently receives a lower dose than the prescribed dose, likely due to an off-axis positioning issue. Conversely, for the metatarsal right and left foot, the dose consistently exceeds the prescription. In this case, the actual dose contribution for each treatment field is likely to be greater in the feet than in other organs.

Conclusion:

Measured doses using GAFchromic film for seven TSEI patients showed a good agreement with expected doses. For small extremities such as hands and feet, underdosing and overdosing were observed, respectively. In vivo dosimetry for TSEI should be employed to identify areas that require boost treatments or shielding and to improve dose homogeneity. Radiochromic film dosimetry is a good choice to achieve this.

Keywords: TSEBT, Gafchromic EBT3 , Mycosis Fungoides

References:

[1] Jones GW, Kacinski BM, Wilson LD, et al. Total skin electron radiation in the management of mycosis fungoides: consensus of the European Organization for Research and Treatment of Cancer (EORTC) Cutaneous Lymphoma Project Group. J Am Acad Dermatol. 2002;47:364–70.

[2] Méndez I, Rovira-Escutia JJ, Casar B. A protocol for accurate radiochromic film dosimetry using Radiochromic.com. Radiol. Oncol 2021;55:369–78. https://doi. org/10.2478/raon-2021-0034.

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Dose and setup verification based on in vivo dosimetry for PBS proton RBE mice studies