Synthetic diamond devices for radio‐oncology applications

Abstract

Diamond exhibits a range of outstanding properties that make it a material of interest for radiation detection and particularly in the field of dosimetry applications. In fact, its crystallographic structure makes it chemically inert and radiation hard. Moreover, its atomic number (carbon Z = 6) close to the equivalent effective atomic number of human soft tissues (Z = 7.4) and of water (reference material in radiotherapy) enables a direct evaluation of the deposited dose without requiring corrections for material nature or energy. Finally, as a bio‐compatible material, it can be sterilised, and it is non‐toxic thus giving strong advantages for medical uses. Natural diamonds are expensive, rare and their use implies a severe gem selection to fabricate reproducible and reliable devices. The emergence of synthetic samples from the chemical vapour deposition (CVD) technique offers new possibilities in the fabrication of ionisation chamber for the particular field of radiotherapy. Previous studies have shown that defect levels present in material clearly influence the device response under irradiation. Therefore, in order to optimise dosimetric characteristics needed in radiotherapy applications, various low and precisely nitrogen concentrations were incorporated in the material during growth. Influence of these incorporations on ionisation chamber response under medical cobalt irradiator is presented in this paper. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Thermoluminescence assessment of 0.5, 1.0 and 4.0 µm thick HFCVD undoped diamond films

“…The effect of nitrogen incorporation in CVD diamond films during growth on the TL performance has been undertaken with the expectation that this may control the trapping level population to improve the TL sensitivity, reproducibility, and dose linearity 19–21. Indeed, optimization of the TL intensity and dose linearity were found through incorporation of 20 ppm nitrogen concentration in the gas phase 20.…”

Hydrogen plasma and atomic oxygen treatments of diamond: Chemical versus morphological effects

“…Diamond films are considered as a prospective material in several fields, including optical windows, 1,2 biological applications, 3,4 and electron emission devices, 5,6 just to name a few. Diamond films are considered as a prospective material in several fields, including optical windows, 1,2 biological applications, 3,4 and electron emission devices, 5,6 just to name a few.…”

“…These conditions are typical for diamond surface cleaning treatment, which also results in a negative electron affinity of the surface. 10,[25][26][27] This spectrum shows that typical pristine CVD diamond film surface contains both sp 3 and sp 2 bonded carbon atoms. 10 The morphology of the samples was studied using AFM ͑Nanoscope IV MultiMode from Veeco͒ operated in tapping mode.…”

Investigation of the suitability of commercially available CVD diamond for megavoltage X-ray dosimetry

“…The peak at 2050 wavenumbers (575 nm) observed in most spectra and the broad background photoluminescence (particularly noticeable in the Diamonex material, Fig. 2(a, b)) are both due to nitrogen-vacancy (NV) complexes in the diamond crystal [22]. The intensity of the 2050-wavenumber peak (relative to the diamond Raman peak) and the background photoluminescence were much higher for the polycrystalline Diamonex material (Fig.…”