High-Resolution Ultrasonic Thermometer for Radiation Dosimetry
Eugene Malyarenko, Joseph Heyman, Heather H. Chen-Mayer, Ronald Tosh
This paper describes recent developments in the area of high-precision This paper describes recent developments in the area of high-precision ultrasonic thermometry with the potential to provide on-site direct determination of radiation dose and its spatial distribution in phantoms for cancer treatment. A non-contact method is demonstrated for measuring small temperature changes without placing sensors directly in the radiated water environment, as prescribed by current calibration standards. This eliminates thermal losses or excess heat due to radiation absorption by the sensor body and housing. The new technique is based on a high-resolution ultrasonic system with an acoustic propagation path in the radiation-heated water tank. A single-channel thermometer measures average water temperature along the acoustic path achieving sensitivity of 3.2 micro Kelvin at room temperature and at four seconds between successive measurements. Both light and ionizing radiation heating data are presented for the analog and digital implementations of a laboratory prototype.