Initial investigation of a novel light-scattering gel phantom for evaluation of optical CT scanners for radiotherapy gel dosimetry

Abstract

There is a need for stable gel materials for phantoms used to validate optical computerized tomography (CT) scanners used in conjunction with radiation-induced polymerizing gel dosimeters. Phantoms based on addition of light-absorbing dyes to gelatine to simulate gel dosimeters have been employed. However, to more accurately simulate polymerizing gels one requires phantoms that employ light-scattering colloidal suspensions added to the gel. In this paper, we present the initial results of using an optical CT scanner to evaluate a novel phantom in which radiation-exposed polymer gels are simulated by the addition of colloidal suspensions of varying turbidity. The phantom may be useful as a calibration transfer standard for polymer gel dosimeters. The tests reveal some phenomena peculiar to light-scattering gels that need to be taken into account when calibrating polymer gel dosimeters.

Antioxidant effect of green tea on polymer gel dosimeter

“…Polymer gel dosimeter is an emerging system and serves as good tool for dose verification in radiotherapy [1,2]. Absorbed dose and the dose can be extracted from different techniques such as Magnetic Resonance Imaging (MRI) [3][4][5], Optical Computed Tomography (Optical CT) [6,7], X-ray CT [8,9], Ultrasound CT (UCT) [10][11][12] and vibrational spectroscopy [13][14][15].…”

Polymer gel dosimetry utilizing a 2D (SE) and a 2D (HASTE) multiple echo sequences

“…Nowadays, different imaging modalities applied for the readout and analysis processes are used. These include Magnetic Resonance Imaging (MRI) [2], Optical Computed Tomography (opt-CT) [3], x-ray CT [4] and Ultrasound [5]. Amongst them, MRI is an established methodology as a readout process in polymer gel dosimetry [6].…”

Dosimetric assessment of the PRESAGE dosimeter for a proton pencil beam

“…Both polymer gels [4] and PRESAGE [5,6] radiochromic plastic dosimeter, in conjunction with optical CT scanner [7,8], have been employed to verify 3-D dose distribution for complex treatments with photon beams, such as IMRT and stereotactic radiosurgery [9,10]. These studies have shown promising results in providing a 3-D dosimetry tools for photon external beam treatments.…”

“…Detailed three-dimensional dosimetric information for a proton beam is crucial for accurate treatment planning design and treatment delivery due to the sharp dose falloff at the end of the beam range and laterally at the field edges [1][2][3]. It is more challenging to measure the 3-D dose distribution of a pencil beam (1 -1.5 cm diameter) because of its small field size as well as the complexity of dose changes in various directions.Both polymer gels [4] and PRESAGE [5,6] radiochromic plastic dosimeter, in conjunction with optical CT scanner [7,8], have been employed to verify 3-D dose distribution for complex treatments with photon beams, such as IMRT and stereotactic radiosurgery [9,10]. These studies have shown promising results in providing a 3-D dosimetry tools for photon external beam treatments.…”