Investigations of high mobility single crystal chemical vapor deposition diamond for radiotherapy photon beam monitoring

Abstract

Articles you may be interested inEvaluation of the dosimetric properties of a synthetic single crystal diamond detector in high energy clinical proton beams Med.Characterization of a synthetic single crystal diamond Schottky diode for radiotherapy electron beam dosimetry Med. Phys. 40, 021712 (2013); 10.1118/1.4774360Single crystal chemical vapor deposited diamond detectors for intensity-modulated radiation therapy applications A preliminary dosimetric characterization of chemical vapor deposition diamond detector prototypes in photon and electron radiotherapy beams Med.The intrinsic properties of diamond make this material theoretically very suitable for applications in medical physics. Until now ionization chambers have been fabricated from natural stones and are commercialized by PTW, but their fairly high costs and long delivery times have often limited their use in hospital. The properties of commercialized intrinsic polycrystalline diamond were investigated in the past by many groups. The results were not completely satisfactory due to the nature of the polycrystalline material itself. In contrast, the recent progresses in the growth of high mobility single crystal synthetic diamonds prepared by chemical vapor deposition ͑CVD͒ technique offer new alternatives. In the framework of the MAESTRO project ͑Methods and Advanced Treatments and Simulations for Radio Oncology͒, the CEA-LIST is studying the potentialities of synthetic diamond for new techniques of irradiation such as intensity modulated radiation therapy. In this paper, we present the growth and characteristics of single crystal diamond prepared at CEA-LIST in the framework of the NoRHDia project ͑Novel Radiation Hard CVD Diamond Detector for Hadrons Physics͒, as well as the investigations of high mobility single crystal CVD diamond for radiotherapy photon beam monitoring: dosimetric analysis performed with the single crystal diamond detector in terms of stability and repeatability of the response signal, signal to noise ratio, response speed, linearity of the signal versus the absorbed dose, and dose rate. The measurements performed with photon beams using radiotherapy facilities demonstrate that single crystal CVD diamond is a good alternative for air ionization chambers for beam quality control.

Diamond dosimeter for small beam stereotactic radiotherapy

“…9 shows the SCDDo current as a function of dose rate and the corresponding fitting curve according to Fowler's equation. The result of the fitting gives a ∆ value of 0.975 ± 0.003, in good agreement with those obtained with natural diamond of PTW dosimeter [15], [30]and with other synthetic single crystal diamonds [31]. Cross-line dose profiles were measured with SCDDo for the smallest field size available with the µMLC m3 (0.6 × 0.6 cm 2 ), by positioning the cable parallel to the beam axis and the smallest dimension of the diamond detection volume (its thickness of 500 µm) in the scanning direction, in order to have the best spatial resolution available.…”

Toward Pulse by Pulse Dosimetry Using an SC CVD Diamond Detector

“…Schottky diodes are expected to have very good linearity. Dose-rate linearities have been measured in singlecrystal CVD diamond detectors by a number of groups [6], [9], [22]- [28], several of whom determined a significant nonlinear response as a function of dose-rate [6], [9], [23], [27], [28]. A variety of methodologies were used, including varying the PRF, varying the source current in the case of X-ray sources, and varying the source to detector distance, which is the method that has been used here.…”

Dosimetric characterization of a synthetic single crystal diamond detector in clinical radiation therapy small photon beams

“…[18][19][20][21][22][23][24] Most papers on diamond dosimeters are dedicated to commercial natural diamond-based detectors from PTW. Polycrystalline chemical vapor deposition (CVD) diamond [25][26][27][28] and CVD or high-pressure high-temperature (HPHT) synthetic single crystal diamond [29][30][31] have been also studied as radiation therapy dosimeters. However, lack of reproducibility, difficulties in controlling impurities incorporation in synthetic crystals, and problems related to encapsulation techniques make the performance of such devices still far from the ones of PTW natural diamond detectors.…”