New water equivalent liquid scintillation solutions for 3D dosimetry

Abstract

Despite recent advances in radiochromic film and gel dosimetry techniques, radiation therapy still lacks an efficient, accurate, and convenient dose measurement method capable of measuring the dose simultaneously over a plane or a volume (3D). A possibility for creating such a 3D method based on observing scintillation photons emitted from an irradiated volume was recently reported [A. S. Kirov et al., Med. Phys. 26, 1069 (1999)]. In the present article, we investigate the potential to use a liquid scintillation solution (LS) as a dose sensitive media and, simultaneously, as a water equivalent phantom material which fills the measurement volume. We show that matching water density in addition to energy absorption properties is important for using the LS solution as a phantom. Through a parametric study of the LS attenuation and absorption coefficients as well as Monte Carlo dose calculations and scintillation efficiency measurements we developed novel LS materials. For the new solutions, the calculated dose in LS is within 8% of the dose to water for depths up to 5 cm for photons having energies between 30 keV and 2 MeV. The new LS solutions, which are loaded with a Si containing compound, retain more than 85% of the scintillation efficiency of the unloaded solutions and exhibit high localization of the scintillation process. The new LS solutions are superior with respect to efficiency and water equivalence to plastic scintillator materials used in dosimetry and may be used apart from the mentioned 3D method.

Calculations and measurements of the scintillator-to-water stopping power ratio of liquid scintillators for use in proton radiotherapy

“…These materials consist of organic solvents containing fluors, the scintillating molecules that emit visible light when exposed to radiation. The use of liquid scintillators for three-dimensional radiation dosimetry was first investigated by Kirov et al (2005; 2000). Their work focused on dosimetry of brachytherapy eye plaques in a small detection volume.…”

3D reconstruction of scintillation light emission from proton pencil beams using limited viewing angles—a simulation study

“…A liquid scintillator detector system has been proposed by Kirov et al (2000) for 3D dosimetry of brachytherapy eye plaques (Kirov et al , 2005). We have previously studied and characterized a liquid scintillator system (Archambault et al , 2012; Beddar et al , 2009; Ponisch et al , 2009; Robertson et al , 2014) for verification of proton beam properties.…”

Optical cone beam tomography of Cherenkov‐mediated signals for fast 3D dosimetry of x‐ray photon beams in water

“…[1][2][3][4][5][6][7][8][9][10][11] Recently, several studies proposed that the inherent optical photons generated in pure water by radiotherapy photon beams via the Cherenkov effect may be imaged and used as a potential surrogate for the relative dose distribution. 12,13 The technique was extended to optical tomography by utilizing a telecentric lens to provide orthographic projections suitable for reconstruction using a simple parallel beam back projection algorithm, similar to telecentric illumination used in previously reported gel dosimetry systems.…”