Ultrasound attenuation computed tomography assessment of PAGAT gel dose

作者：Khoei S^*; Trapp J V; Langton C M

来源：Physics in Medicine and Biology, 2014, 59(15): N129-N137.

DOI：10.1088/0031-9155/59/15/N129

• ultrasound computed tomography
• broasband ultrasound attenuation
• polymer gel dosimetry
• ultrasound attenuation

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.

• 出版日期2014-8-7