The Multigaussian method: a new approach to multichannel radiochromic film dosimetry

TL;DR

The paper introduces the Multigaussian method, a novel multichannel radiochromic film dosimetry approach that models the response as a multivariate Gaussian, improving dose accuracy by accounting for spatial heterogeneities and pre-irradiation scans.

Contribution

It presents the Multigaussian method, a new multichannel dosimetry technique based on Gaussian assumptions, enhancing dose measurement accuracy over existing models.

Findings

Multigaussian outperforms other models in dose accuracy.

Incorporating pre-irradiation scans improves heterogeneity correction.

The method effectively models the response vector with a multivariate Gaussian.

Abstract

The main objective of multichannel radiochromic film dosimetry methods is to correct, or at least mitigate, spatial heterogeneities in the film-scanner response, especially variations in the active layer thickness. To this end, films can also be scanned prior to irradiation. In this study, the abilities of various single channel and multichannel methods to reduce spatial heterogeneities, with and without scanning before irradiation, were tested. A new approach to multichannel dosimetry, based on experimental findings, i.e., the Multigaussian method, is introduced. The Multigaussian method assumes that the probability density function of the response vector formed by the pixel values of the different color channels, including irradiated and non-irradiated scans, follows a multivariate Gaussian distribution. The Multigaussian method provided more accurate doses than the other models under comparison, especially when incorporating the information of the film prior to irradiation.