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Crister Ceberg

Professor

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Reconfiguring a Plane-Parallel Transmission Ionization Chamber to Extend the Operating Range into the Ultra-High Dose-per-pulse Regime

Författare

  • Elise Konradsson
  • Rebecka Ericsson Szecsenyi
  • Pontus Wahlqvist
  • Andreas Thoft
  • Börje Blad
  • Sven Å.J. Bäck
  • Crister Ceberg
  • Kristoffer Petersson

Summary, in English

This study aims to investigate the feasibility of enhancing the charge collection efficiency (CCE) of a transmission chamber by reconfiguring its design and operation. The goal was to extend the range of dose-per-pulse (DPP) values with no or minimal recombination effects up to the ultra-high dose rate (UHDR) regime. The response of two transmission chambers, with electrode distance of 1 mm and 0.6 mm, respectively, was investigated as a function of applied voltage. The chambers were mounted one-by-one in the electron applicator of a 10 MeV FLASH-modified clinical linear accelerator. The chamber signals were measured as a function of nominal DPP, which was determined at the depth of dose maximum using EBT-XD film in solid water and ranged from 0.6 mGy per pulse to 0.9 Gy per pulse, for both the standard voltage of 320 V and the highest possible safe voltage of 1,200 V. The CCE was calculated and fitted with an empirical logistic function that incorporated the electrode distance and the chamber voltage. The CCE decreased with increased DPP. The CCE at the highest achievable DPP was 24% (36%) at 320 V and 51% (82%) at 1,200 V, for chambers with 1 mm (0.6 mm) electrode distance. For the combination of 1,200 V- and 0.6-mm electrode distance, the CCE was»100% for average dose rate up to 70 Gy/s at the depth of dose maximum in the phantom at a source-to-surface distance of 100 cm. Our findings indicate that minor modifications to a plane-parallel transmission chamber can substantially enhance the CCE and extending the chamber's operating range to the UHDR regime. This supports the potential of using transmission chamber-based monitoring solutions for UHDR beams, which could facilitate the delivery of UHDR treatments using an approach similar to conventional clinical delivery.

Avdelning/ar

  • Radiotherapy Physics
  • Medicinsk strålningsfysik, Lund
  • LUCC: Lunds universitets cancercentrum
  • Medicinsk strålningsfysik, Malmö
  • LU profilområde: Ljus och material
  • Rausinglaboratoriet i Lund - Tumörsektionen

Publiceringsår

2024-03-08

Språk

Engelska

Sidor

252-260

Publikation/Tidskrift/Serie

Radiation Research

Volym

201

Issue

3

Dokumenttyp

Artikel i tidskrift

Förlag

Radiation Research Society

Ämne

  • Radiology, Nuclear Medicine and Medical Imaging

Status

Published

Forskningsgrupp

  • Radiotherapy Physics
  • Medical Radiation Physics, Malmö
  • Rausing laboratory of Lund - Tumor section

ISBN/ISSN/Övrigt

  • ISSN: 0033-7587