H. Masoumi - Medical Physics Department, Faculty of Medical Sciences, Tarbiat Modares University
M. Mokhtari-Dizaji - Medical Physics Department, Faculty of Medical Sciences, Tarbiat Modares University
A. Arbabi - Radiotherapy and Oncology Department, Faculty of Medical Sciences, Shahid Beheshti University of Medical Sciences and Health Services
M. Bakhshandeh - Radiology Technology Department , Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran

Gold nanoparticles have been applied much more extensively in radiotherapy. This study used MAGIC-f polymer gel with gold nanoparticles in order to assess the dose-response of the speed of the sound. The MAGIC-f polymer gel with and without nanoparticles were placed under the megavoltage irradiation of Cobalt-60 with the doses of 0-60Gy with the step of 6Gy. Afterwards, the speed of the sound was assessed using an ultrasonic transmission device and the R2 parameter was assessed using Magnetic Resonance Imaging (MRI) at 25°C and 24h after irradiation. The highest sensitivity of ultrasound and MRI parameters was obtained in the range of 6-42Gy, and gel saturation occurred above 48Gy. Additionally, in the linear range of 6-42Gy, the speed of the sound and R2 parameters in MAGIC-f polymer gel was more with gold nanoparticles than without them. The presence of gold nanoparticles increases the absorbed dose. The presence of gold nanoparticles increases the absorbed dose and the speed of the sound can be use for dose - response curve extraction.

Nanoparticles, Radiotherapy, Gel dosimetry, Ultrasound