ESTRO 2024 - Abstract Book

S308

Brachytherapy - Head & neck, skin, eye

ESTRO 2024

2. Shelton ME, Adamson AS. Review and Update on Evidence-Based Surgical Treatment Recommendations for Nonmelanoma Skin Cancer. Dermatologic Clinics. oct 2019;37(4):425-33.

3. Guinot JL, Rembielak A, Perez-Calatayud J, Rodríguez-Villalba S, Skowronek J, Tagliaferri L, et al. GEC-ESTRO ACROP recommendations in skin brachytherapy. Radiother Oncol. mars 2018;126(3):377-85.

4. Tagliaferri L, Giarrizzo I, Fionda B, Rigante M, Pagliara MM, Casà C, et al. ORIFICE (Interventional Radiotherapy for Face Aesthetic Preservation) Study: Results of Interdisciplinary Assessment of Interstitial Interventional Radiotherapy (Brachytherapy) for Periorificial Face Cancer. J Pers Med. 24 juin 2022;12(7):1038.

1734

Digital Poster

106 Ru brachytherapy dosimetry data verification using diodes traceable to EBRT metrology standards

Simon Dahlander 1,2 , Linda Persson 3,1 , Ilias Billas 4 , Graham Bass 4 , Thorsten Sander 4 , Åsa Carlsson Tedgren 1,2,5

1 Karolinska Institute, Oncology-Pathology, Stockholm, Sweden. 2 Karolinska University Hospital, Medical Radiation Physics and Nuclear Medicine, Stockholm, Sweden. 3 Swedish Radiation Safety Authority, National Metrology Laboratory, Stockholm, Sweden. 4 National Physical Laboratory, Acoustics and Ionising Radiation, Teddington, United Kingdom. 5 Linköping University, Medical and Health Sciences, Linköping, Sweden

Purpose/Objective:

In most radiotherapy, performing independent verification of the treatment fields is standard practice. However, for 106 Ru eye plaque brachytherapy there has been no such standard method available. This has led to many hospitals performing these treatments without independent verification of plaque absorbed dose rate to water [1]. To full fill COUNCIL DIRECTIVE 2013/59/EURATOM and to enhance the safety of brachytherapy treatments for intraocular tumors, we devised an independent measurement protocol to determine depth-dose curves from 106 Ru eye-plaques using a new high precision setup equipment and diode detector.

Material/Methods:

The absorbed dose rate to water was measured from five plaques (Bebig Eckert and Ziegler), four CCB types and one CCA type, using three PTW (microSilicon (type 60023) diode detectors with a prototype, dedicated setup equipment from the plaque vendor (see Figure 1). The diodes were calibrated in 60 Co at a national secondary standards metrology laboratory as well as cross-calibrated in 6 MeV electron field at a radiotherapy clinic. Correction factors along the lines of the TRS-398 protocol [2] were calculated with the PENELOPE Monte Carlo code. Absorbed dose rate measurements were done in a water-filled PMMA phantom, equipped with a plaque attachment. Furthermore, the depth-dose curves were validated against vendor data and data from alanine detectors measurements. The alanine measurements were performed at a primary standard laboratory and are traceable to a 60 Co primary standard of absorbed dose to water.