#Aga image convert to dctv update#

Each module contains a scintillating crystal array, a photodiode array, and the ADAS, which contains multiple integrator channels that are multiplexed into the ADCs. Each module transforms the incident X-rays into electrical signals routed into the multichannel analog data acquisition system (ADAS). It is comprised of multiple modules, which are depicted in Figure 2. The CT detector is the central component of the entire system architecture and, indeed, is the heart of the CT system. Computed TomographyĬomputed tomography (CT) also uses ionizing radiation but, unlike digital X-ray technology, it is based on an arc-shaped detector system synchronously rotating with an X-ray source and utilizes more sophisticated processing techniques to produce high resolution 3D images of blood vessels, soft tissue, and more. There are a wide range of discrete ADCs and integrated analog front ends to enable various types of DR imaging systems with increased dynamic range, finer resolution, higher detection efficiency, and lower noise.įigure 1.

Digital X-ray systems use 14-bit to 18-bit ADCs with SNR levels ranging from 70 dB up to 100 dB depending on the type of the imaging system and its requirements. The signal-to-noise ratio (SNR) is another important parameter that defines the intrinsic ability of the system to faithfully represent the anatomic features of the imaged body. This value is binned into a finite number of discrete levels defined by the bit-depth of an ADC. In the intensity dimension, the digital output signal of an ADC represents the integrated amount of X-ray photons absorbed in a given pixel over a specific exposure time.

#Aga image convert to dctv update#

Flat panel detectors with millions of pixels and typical update rates as high as 25 fps to 30 fps employ channel multiplexing and multiple ADCs with sampling rates up to several dozens of MSPS to meet the minimum conversion time without sacrificing accuracy. In the spatial dimension, the minimum sampling rate is defined by the pixel matrix size of the detector and the update rate for real-time fluoroscopy imaging. The quality of this image depends on the signal sampling in the spatial and intensity dimensions. The resulting electrical signal is amplified and converted into a digital domain to produce an accurate digital representation of the X-ray image. The detector converts the X-ray photons into electrical charges that are proportional to the energy of the incident particles. The X-rays passing through the body are attenuated by tissues of different radiographic opacity and projected on a flat panel detector system, as shown schematically in Figure 1. Digital Radiographyĭigital radiography (DR) is based on physical principles common to all conventional absorption-based radiography systems. This article discusses these design challenges in the context of different imaging modalities and gives an overview of advanced data converters and integrated solutions needed to make them work at optimum levels.

The data converter constitutes the most demanding challenges imposed by medical imaging on the electronics design in terms of required dynamic range, resolution, accuracy, linearity, and noise. Its signal chain comprises a sensing element, a low noise amplifier (LNA), a filter, and an analog-to-digital converter (ADC), of which the latter is the main subject of this article. However, it is its performance that has a crucial impact on the resulting image quality of the complete system. This tiny functional front-end block is hidden deep inside a complex machine. This article considers the main types of modern medical imaging systems that utilize fundamentally different physical principles and processing techniques but have one thing in common-an analog data acquisition front end serving for signal conditioning and conversion of raw imaging data into a digital domain. Since then it has developed into an extensive scientific discipline that, in its widest sense, designates diverse techniques for noninvasive visualization of the internal aspects of the body. The discovery of X-radiation by Wilhelm Conrad Röntgen in 1895 earned him the first Nobel Prize in Physics and laid the historical foundations for the field of medical imaging.

High Performance Data Converters for Medical Imaging Systems