New methods of dosimetry in computed tomography (CT) X-ray fields require the use of high-resolution detectors instead of pencil-type ionization chambers typically used for CT dose index (CTDI) measurements. This paper presents a study on the suitability of a wide range of ionization chambers, diodes, and a two-dimensional detector array, used primarily in radiation therapy, for CT and cone-bea...

There is a large scatter in the results of X-ray analysis with solid-state detectors suggesting methodological origin. In order to improve the methodology, detector response functions have been investigated by many researchers and analysts. This was necessary as the departure of the response function of some detector-signal processing electronics from the normally assumed Gaussian line shape ca...

Recent technological developments and new topology designs have made semiconductor drift detectors ideal devices for high-resolution x-ray spectrometry. In this paper the basic topology of a semiconductor drift detector with on-chip electronics specially designed for x-ray spectrometry is reviewed. These devices have been used for the first time in x-ray and g-ray spectroscopy applications. In ...

The first X-ray observation of the Seyfert 2 galaxy NGC5252 is reported. ASCA collected ∼ 4000 photons/detector enough to perform an accurate spectral analysis of this source. The luminosity of NGC5252 is L X (0.7-10 keV) ≃ 2.6 ×10 43 erg s −1 , typical of a Seyfert 1 galaxy. A simple description of the spectrum with a single power law is ruled out by the SIS data which shows a strong soft exce...

background: the number of interventional cardiology (ic) procedures has increased rapidly. coronary angiography (ca) and percutaneous transluminal coronary angioplasty (ptca) are now widely performed as a matter of routine, and they are considered safe procedures for experienced cardiologists. however, it is also known that these procedures are associated with high radiation doses due to long f...

We have developed a prototype imaging system that can perform simultaneous x-ray transmission CT and SPECT phantom studies. This system employs a 23-element high-purity-germanium detector array. The detector array is coupled to a collimator with septa angled toward the focal spot of an x-ray tube. During image acquisition, the x-ray fan beam and the detector array move synchronously along an ar...

X-ray computed tomography (CT), introduced into clinical practice in 1972, was the first of the modern slice-imaging modalities. To reconstruct images mathematically from measured data and to display and to archive them in digital form was a novelty then and is commonplace today. CT has shown a steady upward trend with respect to technology, performance and clinical use independent of predictio...