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N. Lanconelli,
R. Campanini,
E. Iampieri,
R. Pani,
M.N. Cinti,
P. Bennati,
N. Belcari,
M. Camarda,
L. Spontoni,
S. Vecchio, P. Randaccio,
P. Russo,
A. Del Guerra
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ABSTRACT: This work is developed within the framework of a larger project, which aims to develop a multimodal CT-SPET system dedicated to breast imaging. The goal of this paper is to optimize the choice of the various parameters involved in the design of a SPET system dedicated to breast imaging. In particular, we simulated different collimators, different tumor to background (T/B) ratios for two different spherical tumors with diameters of 5 mm and 8 mm. The performance of the explored cameras were analyzed in terms of SNR and image contrast (IC) values, calculated on the reconstructed images. In addition, we investigated the visibility limits of the system, by modifying the tumor size, the T/B value, and the diameter of the breast phantom (8 cm, 10 cm, and 13 cm). As a general tendency, we found out that a high-resolution camera is preferable, in terms of image contrast. On the other hand, the general purpose collimator seems to give a smoother image, giving rise to SNR values comparable to those obtained with the high-resolution collimator, even with a reduced contrast. High-sensitivity collimators seem to give a worse response on the reconstructed images. The 8 mm tumor is clearly visible for all the simulated conditions, even if it could be very close to the visibility limit for the high-sensitivity collimator. The 5 mm tumor is close to the visibility limit for general purpose and high-resolution collimators, for a T/B ratio equal to 10:1 and is not visible with high-sensitivity collimator. The smaller tumor is almost obscured by the background with the thickest breast (13 cm diameter).
Nuclear Science Symposium Conference Record, 2006. IEEE; 12/2006
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ABSTRACT: A fast parallel readout system based on a PCI board has been developed in the framework of the Medipix collaboration.1The 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.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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ABSTRACT: An imaging system based on the Medipix2, a single photon counting pixel readout ASIC for X-ray hybrid detectors, has been developed for tomography imaging applications. The “quad assembly” houses four Medipix2 chips placed in a 2×2 array with an active area of about 3×3 cm2. The readout system we present consists of four electronic cards and exploits the Medipix2 parallel readout mode and a fast optical link based on the Glink standard, giving high flexibility and EM interference immunity over long distance connections. A PCI board interfaces the imaging system to a standard PC. We expect a frame rate of 25 frame/s which allows real-time X-ray imaging acquisitions and fast computed tomography (CT) scanning. In this paper, we describe the DAQ project and the status of development.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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ABSTRACT: A commercially available computed radiography (CR) system for dental radiography was used to produce images from radiolabeled polyacrilamide gel electrophoresis (PAGE) assays. Typically, similar investigations require specific and expensive autoradiography devices. The CR unit was characterized in terms of sensitivity and fading by means of a 90Sr source that well simulates the experimental conditions, and then used for quantitative analyses of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) polymerase-independent ribonuclease H (RNase H) activity monitored by PAGE analysis. The results showed that the present methodology allows quantifying effectively the RNase H catalyses and that the obtained data are in good agreement with previous reference works. Finally, in order to further validate the present method in terms of relationship between enzyme activity, the rate of products formation and signal intensity, a PAGE analyses of the HIV-1 RNase H inhibition by the known diketo acid derivative RDS1643 was carried out.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
