A carbon fiber-based radiation sensor for dosimetric measurement in radiotherapy

A prototype sensor was designed and fabricated to explore the application of carbon fibers for absorbed dose measurements in the ionizing radiation field used for therapeutic radiology. The carbon fiber-based sensor has a 1.8 × 1.8 cm2 sensing area. Both 6 and 15 MV X-ray beams produced by a Varian Clinac 21 EX medical linear accelerator were used to test the sensor. Radiation dosimetric measurements were performed by varying the dose rates, total dose, and field sizes to characterize various properties of the sensor. For the given dose range from 0 to 600 monitor units, the sensor displayed an excellent linear response. This sensor can be used for dosimetric measurements and real-time dose rate monitoring. Compared to existing MV X-ray measurement technologies in radiotherapy, this prototype sensor provides many advantages over commercially available dosimeters: (i) ease of operation; (ii) low noise at room temperature; (iii) light in mass; (iv) low voltage requirements; (v) potential for miniaturization; and (vi) real-time signal measurement. A higher spatial resolution can be achieved by miniaturizing the physical size of the current sensor design.