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Direct analysis of molybdenum target generated x-ray spectra with a portable device

Stumbo, Simone and Bottigli, Ubaldo and Golosio, Bruno and Oliva, Piernicola and Tangaro, Sonia (2004) Direct analysis of molybdenum target generated x-ray spectra with a portable device. Medical Physics, Vol. 31 (10), p. 2763-2770. eISSN 0094-2405. Article.

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DOI: 10.1118/1.1785891


In routine applications, information about the photon flux of x-ray tubes is obtained from exposure measurements and cataloged spectra. This approach relies mainly on the assumption that the real spectrum is correctly approximated by the cataloged one, once the main characteristics of the tube such as voltage, target material, anode angle, and filters are taken account of. In practice, all this information is not always available. Moreover, x-ray tubes with the same characteristics may have different spectra. We describe an apparatus that should be useful for quality control in hospitals and for characterizing new radiographic systems. The apparatus analyzes the spectrum generated by an x-ray mammographic unit. It is based on a commercial CZT produced by AMPTEK Inc. and a set of tungsten collimator disks. The electronics of the CZT are modified so as to obtain a faster response. The signal is digitized using an analog to digital converter with a sampling frequency of up to 20 MHz. The whole signal produced by the x-ray tube is acquired and analyzed off-line in order to accurately recognize pile-up events and reconstruct the emitted spectrum. The energy resolution has been determined using a calibrated x-ray source. Spectra were validated by comparison of the HVL measured using an ionization chamber.

Item Type:Article
ID Code:1939
Uncontrolled Keywords:Molybdenum, X-ray spectra, diagnostic radiography, spectral analysis, tungsten, collimators, ionisation chambers, mammography, calibration, image sampling, image reconstruction, medical image processing
Subjects:Area 02 - Scienze fisiche > FIS/07 Fisica applicata (a beni culturali, ambientali, biologia e medicina)
Divisions:001 Università di Sassari > 03 Istituti > Matematica e fisica
Publisher:American Association of Physicists in Medicine
Deposited On:18 Aug 2009 10:06

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