FLASH: Revolution in RadiationTherapy
FLASH. Have you already heard of it? This treatment method for tumor diseases is a new, promising approach in radiationtherapy. In FLASH therapy an ultra-high dose rate is applied in less than one second. FLASH radiations place special demands on dosimetric measurement technology. 3 questions and 3 answers to Rafael Kranzer, R&D Project Manager, and Dr. Frank Schwamm, Product Manager, who develop FLASH dosimetry solutions at PTW.
In 2019, the EU launched a project with the aim of developing a method for measuring dose at the ultra-high pulse dose rates involved in FLASH radiotherapy. What was this project about, and what role did PTW play in this project?
FLASH is a new promising treatment technique in radiation therapy. Before this treatment method can be implemented in clinical practice, there must be a procedure that makes it possible to precisely measure radiation dose at ultra-high pulse dose rates. The European Union launched a research project called UHDpulse to pave the way for it.
Among other things, the objectives of the project were: …
… to develop a metrological framework for dose measurements at ultra-high pulse dose rates.
… to examine existing, but also newly developed, detector systems for their suitability for dosimetry of beams with ultra-high dose rate or ultra-short pulse duration.
… to develop reference standards for dose measurements at ultra-high pulse dose rates and suitable measurement methods.
PTW was a partner of this project and involved in various work packages. One of these packages was the development of suitable detectors for FLASH dosimetry.
In this context, PTW pioneered the development of a new detector. What distinguishes this detector and why can’t existing detectors be used for dose measurement in FLASH therapy?
Dr. Frank Schwamm:
The dose measurement of FLASH radiation beams places special demands on detectors. PTW recognized this early on and was looking for suitable solutions for active real-time dosimetry. New challenges arise for both reference and relative dosimetry.
In reference dosimetry on conventional linear accelerators, the absolute dose is typically measured with ionization chambers. Since FLASH radiation uses ultra-high dose rates, recombination effects occur in the ionization chambers resulting in erroneous measurement values. PTW thoroughly investigated this problem, developed suitable detectors for dose measurement of FLASH radiation and has already tested them for this particular application.