Temperature- and frequency-dependent ultrasound response of a Poly(N-vinylcaprolactam) polymer gel dosimeter

Ammar A. Oglat; Khalid A Rabaeh; Mohammed Dawood Salman; Molham M Eyadeh; Kholoud Zyoid

doi:10.46481/jnsps.2026.3305

Authors

Ammar A. Oglat
[email protected]

Department of Medical Imaging, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa 13133, Jordan
Khalid A Rabaeh
Department of Medical Imaging, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa 13133, Jordan
Mohammed Dawood Salman
School of Physics, Universiti Sains Malaysia, 11700 Penang, Malaysia
Molham M Eyadeh
Department of Physics, Faculty of Science, Yarmouk University, Irbid 21163, Jordan
Kholoud Zyoid
Department of Medical Imaging, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa 13133, Jordan

Keywords:

Poly(N-vinylcaprolactam) polymer gel,, ultrasound dosimetry, speed of sound, attenuation coefficient

Abstract

Poly(N-vinylcaprolactam) (PNVCl) polymer gels have recently been proposed for radiation dosimetry; however, their ultrasound response remains inadequately defined. This study assessed the feasibility of pulse-echo ultrasonography for evaluating the dose response of a PNVCl polymer gel dosimeter. Gel samples composed of gelatin type A, deionized water, BIS, PNVCl, and tetrakis(hydroxymethyl)phosphonium chloride (THPC) were synthesized and irradiated with 6 MV photon beams. Dose-response measurements were performed from 0 to 30 Gy at 200 cGy min^-1, and dose-rate dependence was assessed at 100, 300, and 600 cGy min^-1 for doses of 5 and 10 Gy. Ultrasound measurements were acquired with transducers operating between 1 and 4 MHz. The speed of sound and attenuation coefficient were determined using pulse-echo time-of-flight and frequency-domain analyses, respectively. All ultrasonic parameters increased with absorbed dose, with the clearest linear response observed at 2 MHz. The response was temperature dependent, with higher sensitivity at room temperature than at 15 ^oC. Dose rate and photon beam energy showed no clear influence on the ultrasonic response within the investigated range. These findings support pulse-echo ultrasonography as a practical method for assessing PNVCl polymer gel dosimeters, provided that temperature is carefully controlled and temperature-specific calibration curves are used.

Dimensions

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