title: Ultrasound attenuation computed tomography assessment of PAGAT gel dose.
abstract: Ultrasound has been previously investigated as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose responses. We extend previous work utilizing a new computed tomography ultrasound scanner comprising of two identical 5 MHz, 128-element linear-array ultrasound transducers, co-axially aligned and submerged in water as a coupling agent, with rotational of the gel dosimeter between the transducers facilitated by a robotic arm. We have investigated the dose-dependence of both ultrasound bulk attenuation and broadband ultrasound attenuation (BUA) for the PAGAT gel dosimeter. The ultrasound bulk attenuation dose sensitivity was found to be 1.46  ±  0.04 dB m( -1) Gy( -1), being in agreement with previously published results for PAG and MAGIC gels. BUA was also found to be dose dependent and was measured to be 0.024  ±  0.003 dB MHz( -1) Gy( -1); the advantage of BUA being its insensitivity to frequency-independent attenuation mechanisms including reflection and refraction, thereby minimizing image reconstruction artefacts.
authors: School of Chemistry, Physics, & Mechanical Engineering, Institute of Health & Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.
authors: S
authors: S
authors: Khoei
authors: J V
authors: JV
authors: Trapp
authors: C M
authors: CM
authors: Langton
mesh_terms: D005782:Gels / Q000528:radiation effects*; D011874:Radiometry / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014465:Ultrasonics / Q000295:instrumentation / Q000379:methods*
chemical_list: D005782:Gels