Comparison of two portable solid state detectors with an improved collimation and alignment device for mammographic x-ray spectroscopy

Abstract

We describe a portable system for mammographic x-ray spectroscopy, based on a 2 X 2 X 1 mm3 cadmium telluride (CdTe) solid state detector, that is greatly improved over a similar system based on a 3 X 3 X 2 mm3 cadmium zinc telluride (CZT) solid state detector evaluated in an earlier work. The CdTe system utilized new pinhole collimators and an alignment device that facilitated measurement of mammographic x-ray spectra. Mammographic x-ray spectra acquired by each system were comparable. Half value layer measurements obtained using an ion chamber agreed closely with those derived from the x-ray spectra measured by either detector. The faster electronics and other features of the CdTe detector allowed its use with a larger pinhole collimator than could be used with the CZT detector. Additionally, the improved pinhole collimator and alignment features of the apparatus permitted much more rapid setup for acquisition of x-ray spectra than was possible on the system described in the earlier work. These improvements in detector technology, collimation and ease of alignment, as well as low cost, make this apparatus attractive as a tool for both laboratory research and advanced mammography quality control.

Progress in the Development of CdTe and CdZnTe Semiconductor Radiation Detectors for Astrophysical and Medical Applications

“…CdTe and CdZnTe detectors are also suitable for the development of portable systems for mammographic X-ray spectroscopy [67,100-102]. A typical mammographic unit, based on a X-ray tube with Mo target [103], produces X-ray spectra characterized by a continuous distribution (1 – 40 keV) with discrete sharp lines superimposed (Mo fluorescent lines: K α = 17.44 keV and K β = 19.63 keV).…”

Monte Carlo simulation of the response functions of CdTe detectors to be applied in x-ray spectroscopy

“…Nevertheless, experimental determination of x-ray spectra is a complex task, due to the spectral distortion due to the inherent detector efficiency, escape of secondary radiation, incomplete charge collection and carrier trapping effects (Di Castro et al, 1984;O'Foghludha and Johnson, 1981;Matsumoto et al, 2000;Wilkinson et al, 2001;Miyajima and Imagawa, 2002;Künzel et al, 2004;Abbene et al, 2007;Tomal et al, 2011Tomal et al, , 2012. Thus, a common approach to accurate spectra determination is based on proper correction of the measured pulse-height distribution for the energy response function of the detector effects (Di Castro et al, 1984;Tomal et al, 2011) In the last years, most of the measurements of x-ray spectra at diagnostic energy range have been performed with portable CdTe detectors (Miyajima and Imagawa, 2002;Künzel et al, 2004;Bottigli et al, 2006;Abbene et al, 2007). These detectors have several advantages for x-ray spectroscopy due to its high atomic number and high detection efficiency.…”

Breast tissue decomposition with spectral distortion correction: A postmortem study

“…[42][43][44] However, the detector response may become nonlinear under such high count rates due to various artifacts such as pulse pileup, characteristic escape, and charge-sharing. [45][46][47][48] Spectral CT imaging depends critically on a reliable measure of the energy-dependent attenuation coefficients for different materials. The presence of nonlinear detector response leads to substantial distortions in the recorded spectral information, which can severely limit the detector's energy discriminating capability.…”