1,720,968 research outputs found
MPRS: Medipix Parallel Readout System for Angiography Digital Imaging
No full textA fast readout system for the Medipix2 pixel chip has been developed for digital angiography applications to allow real time X-ray imaging of contrast media flowing in blood vessels. The readout system is designed to acquire data coming from the 32-bit Medipix2 parallel port of a maximum of eight chips at a rate of 25 frames per second. The readout electronics is peripheral component interconnect (PCI) bus-based and consists of two boards: the motherboard directly interfacing the chip for settings and data flow and the PCI board linking the motherboard to the bus. With parallel readout, a transfer rate of up to 64 MByte/s has been achieved
Medipix2 parallel readout system
No full textA fast parallel readout system based on a PCI board has been developed in the framework of the Medipix collaboration. (1) The readout electronics consists of two boards: the motherboard directly interfacing the Medipix2 chip, and the PCI board with digital I/O ports 32 bits wide. The device driver and readout software have been developed at low level in Assembler to allow fast data transfer and image reconstruction. The parallel readout permits a transfer rate up to 64 Mbytes/s. (C) 2003 Elsevier Science B.V. All rights reserved
PCI card with DMA capabilities for digital imaging detectors
No full textA readout card based on the standard PCI 32-bit/33 MHz bus has been developed for the fast readout of digital systems. The PCI card exploits a PCI bridge chip with Direct Memory Access (DMA) capabilities which permits to obtain a measured throughput up to 90 Mbytes/s. The PCI card has two high-density 80-pin connectors for data I/O; an external system acquisition card can be connected through two flat cables. A powerful programmable logic FPGA provides the management of the I/O lines; by default, 32 input and 32 output single-ended lines (CMOS) plus six LVDS lines are provided, but the FPGA allows several different I/O configurations depending on the specific application requirements. Another programmable device manages the control and status signals of the local bus and the Synchronous Static RAM available for data storage. Due to its main features like the configurable I/O patterns and the high throughput, this PCI card is suitable for applications like the fast readout of imaging acquisition systems. (c) 2006 Elsevier B.V. All rights reserved
A simulation tool to support teaching and learning the operation of x-ray imaging systems
No full textWe present a software tool for the simulation of an X-ray imaging systems. It consists of three virtual objects: the X-ray source, the human body and the detector. The X-ray source is modeled as a radiological tube for which the user can modify the tube potential, the anode material, the tube load, the filtration and some geometric parameters, such as source-skin distance, orientation and field size. The virtual body consists of a 3D voxel matrix in which CT numbers for each point of the body are stored, obtained from tomographic slices. The interactions of X-rays passing through the body are evaluated using pencil beam technique. The image is obtained computing the dose absorbed by the detector and converting it into optical density by the use of a proper response function. The dose absorbed in each point of the body is also computed and can be visualized both in 2D and 3D representations. The influence of each parameter on the beam spectrum, on the image quality and on the dose to the patient can be observed interactively. (c) 2005 IPEM. Published by Elsevier Ltd. All rights reserved
A portable acquisition system based on USB standard for the Medipix2 X-Ray detector
No full textWe describe a portable readout system for an X-Ray hybrid detector based on the Medipix2 pixel readout chip. The Medipix2 chip (256 x 256 square pixels with 55 mu m pitch) is bump-bonded with a pixellated Silicon sensor 300-micron thick. The readout system consists of a simple small size electronic card based on a single powerful microcontroller and can be connected to a PC through the widespread Universal Serial Bus (USB) interface. The reduced size of the final card (3.8 cm x 4.8 cm) makes it suitable for special applications like dental radiology
Design and test of data acquisition systems for the Medipix2 chip based on PC standard interfaces
No full textWe describe two readout systems for hybrid detectors using the Medipix2 single photon counting chip, developed within the Medipix Collaboration. The Medipix2 chip (256 x 256 pixels, 55 mu m pitch) has an active area of about 2 cm(2) and is bump-bonded to a pixel semiconductor array of silicon or other semiconductor material. The readout systems we are developing are based on two widespread standard PC interfaces: parallel port and USB (Universal Serial Bus) version 1.1. The parallel port is the simplest PC interface even if slow and the USB is a serial bus interface present nowadays on all PCs and offering good performances. (c) 2005 Elsevier B.V. All rights reserved
A dedicated processor for Monte Carlo computation in radiotherapy
No full textA dedicated processor for Monte Carlo computation in radiotherapy treatment lanning on FPGA based hardware
is being developed at INFN, Cagliari. When performing Monte Carlo simulations of the radiation dose delivered to the human body, the Compton interaction of a photon with an electron is
simulated. A fast, pipelined, cost effective design for real time simulation of the Compton interaction had been implemented. The inputs to the system are the energy and the normalized direction vectors of the incoming hoton. The energy and the direction vectors of the scattered photon and the scattered electron are calculated. The energy distribution by the scattered
electron along its path in a voxel space is then calculated which can be used to construct maps of dose distribution in real time
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