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The performance of a prototype device designed to evaluate quality parameters of radiological equipment: Complementary study. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.02.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Santos JC, Tomal A, Furquim TA, Fausto AMF, Nogueira MS, Costa PR. Direct measurement of clinical mammographic x-ray spectra using a CdTe spectrometer. Med Phys 2017; 44:3504-3511. [DOI: 10.1002/mp.12287] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 03/29/2017] [Accepted: 04/11/2017] [Indexed: 01/17/2023] Open
Affiliation(s)
- Josilene C. Santos
- Instituto de Física; Universidade de São Paulo; São Paulo SP 05508-090 Brazil
| | - Alessandra Tomal
- Instituto de Física Gleb Wataghin; Universidade Estadual de Campinas; Campinas SP 13083-859 Brazil
| | - Tânia A. Furquim
- Instituto de Física; Universidade de São Paulo; São Paulo SP 05508-090 Brazil
| | - Agnes M. F. Fausto
- Departamento de Ciências Exatas e Tecnológicas; Universidade Estadual de Santa Cruz; Ilhéus BA 45662-900 Brazil
| | - Maria S. Nogueira
- Centro de Desenvolvimento de Tecnologia Nuclear; Comissão Nacional de Energia Nuclear; Belo Horizonte MG 31270-901 Brazil
| | - Paulo R. Costa
- Instituto de Física; Universidade de São Paulo; São Paulo SP 05508-090 Brazil
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Tomal A, Santos J, Costa P, Lopez Gonzales A, Poletti M. Monte Carlo simulation of the response functions of CdTe detectors to be applied in x-ray spectroscopy. Appl Radiat Isot 2015; 100:32-7. [DOI: 10.1016/j.apradiso.2015.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 12/19/2014] [Accepted: 01/07/2015] [Indexed: 11/29/2022]
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Tomal A, Cunha D, Poletti M. Comparison of beam quality parameters computed from mammographic x-ray spectra measured with different high-resolution semiconductor detectors. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2013.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abbene L, Gerardi G, Principato F, Sordo SD, Raso G. Direct measurement of mammographic X-ray spectra with a digital CdTe detection system. SENSORS (BASEL, SWITZERLAND) 2012; 12:8390-404. [PMID: 22969406 PMCID: PMC3436035 DOI: 10.3390/s120608390] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 11/16/2022]
Abstract
In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate X-ray spectroscopy in mammography (1-30 keV). The DPP system performs a height and shape analysis of the detector pulses, sampled and digitized by a 14-bit, 100 MHz ADC. We show the results of the characterization of the detection system both at low and high photon counting rates by using monoenergetic X-ray sources and a nonclinical X-ray tube. The detection system exhibits excellent performance up to 830 kcps with an energy resolution of 4.5% FWHM at 22.1 keV. Direct measurements of clinical molybdenum X-ray spectra were carried out by using a pinhole collimator and a custom alignment device. A comparison with the attenuation curves and the half value layer values, obtained from the measured and simulated spectra, from an ionization chamber and from a solid state dosimeter, also shows the accuracy of the measurements. These results make the proposed detection system a very attractive tool for both laboratory research, calibration of dosimeters and advanced quality controls in mammography.
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Affiliation(s)
- Leonardo Abbene
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
| | - Gaetano Gerardi
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
| | - Fabio Principato
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
| | - Stefano Del Sordo
- INAF/IASF Palermo, Via Ugo La Malfa 153, Palermo 90146, Italy; E-Mail:
| | - Giuseppe Raso
- Dipartimento di Fisica, Università di Palermo,Viale delle Scienze, Edificio 18, Palermo 90128, Italy; E-Mails: (G.G.); (F.P.); (G.R.)
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David MG, Pires EJ, Bernal MA, Peixoto JG, Dealmeida CE. Experimental and Monte Carlo-simulated spectra of standard mammography-quality beams. Br J Radiol 2012; 85:629-35. [PMID: 22010026 PMCID: PMC3479875 DOI: 10.1259/bjr/73088072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 02/08/2011] [Accepted: 02/16/2011] [Indexed: 11/05/2022] Open
Abstract
UNLABELLED A spectrometric study of standard mammography-quality beams by using experimental and Monte Carlo simulation methods was carried out in this work. The qualities of these beams are described according to the International Electrotechical Commission 61267 standard and the Technical Report Series 457 International Atomic Energy Agency report. Specifically, the non-attenuated RQR-M beam series was studied. METHODS A Si-PIN diode-based spectrometer and the PENELOPE Monte Carlo code (v. 2008F1) were used for experiments and simulations, respectively. In addition, an ionization chamber was used to determine the half-value layers (HVLs) of each beam quality. The measurements were done in the mammography dosimeter calibration setup of our laboratory, and the Monte Carlo simulations reproduced such conditions. RESULTS The relative differences between the HVLs calculated from experimental and simulated spectra were lower than 2.4% for all the beam qualities studied. These differences are 1.2% and 3.1% when comparing the HVLs calculated from the experimental and simulated spectra to those determined by using the ionization chamber, respectively. A semi-empirical relation was found to obtain the nominal tube potential from the effective tube potential. CONCLUSION According to our results, the mammography beams used in this work have energy spectra similar to clinical beams.
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Affiliation(s)
- M G David
- Laboratório de Ciências Radiológicas, Universidade do Estado do Rio de Janeiro, Brazil.
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Künzel R, Okuno E. Effects of the particle sizes and concentrations on the X-ray absorption by CuO compounds. Appl Radiat Isot 2012; 70:781-4. [DOI: 10.1016/j.apradiso.2011.12.040] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/13/2011] [Accepted: 12/22/2011] [Indexed: 11/30/2022]
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Tomal A, Cunha DM, Antoniassi M, Poletti ME. Response functions of Si(Li), SDD and CdTe detectors for mammographic x-ray spectroscopy. Appl Radiat Isot 2011; 70:1355-9. [PMID: 22169681 DOI: 10.1016/j.apradiso.2011.11.044] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 11/19/2011] [Accepted: 11/19/2011] [Indexed: 11/18/2022]
Abstract
In this work, the energy response functions of Si(Li), SDD and CdTe detectors were studied in the mammographic energy range through Monte Carlo simulation. The code was modified to take into account carrier transport effects and the finite detector energy resolution. The results obtained show that all detectors exhibit good energy response at low energies. The most important corrections for each detector were discussed, and the corrected mammographic x-ray spectra obtained with each one were compared. Results showed that all detectors provided similar corrected spectra, and, therefore, they could be used to accurate mammographic x-ray spectroscopy. Nevertheless, the SDD is particularly suitable for clinic mammographic x-ray spectroscopy due to the easier correction procedure and portability.
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Affiliation(s)
- A Tomal
- Departamento de Física, FFCLRP, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil
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Abbene L, Gerardi G, Principato F, Del Sordo S, Ienzi R, Raso G. High-rate x-ray spectroscopy in mammography with a CdTe detector: A digital pulse processing approach. Med Phys 2010; 37:6147-56. [DOI: 10.1118/1.3512804] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Krmar M, Bucalović N, Baucal M, Jovančević N. Possible use of CdTe detectors in kVp monitoring of diagnostic x-ray tubes. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT 2010; 622:256-260. [PMID: 21037976 PMCID: PMC2964844 DOI: 10.1016/j.nima.2010.07.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
It has been suggested that kVp of diagnostic X-ray devices (or maximal energy of x-ray photon spectra) should be monitored routinely; however a standardized noninvasive technique has yet to be developed and proposed. It is well known that the integral number of Compton scattered photons and the intensities of fluorescent x-ray lines registered after irradiation of some material by an x-ray beam are a function of the maximal beam energy. CdTe detectors have sufficient energy resolution to distinguish individual x-ray fluorescence lines and high efficiency for the photon energies in the diagnostic region. Our initial measurements have demonstrated that the different ratios of the integral number of Compton scattered photons and intensities of K and L fluorescent lines detected by CdTe detector are sensitive function of maximal photon energy and could be successfully applied for kVp monitoring.
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Affiliation(s)
- M Krmar
- Physics Department, University of Novi Sad, Novi Sad, Serbia
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Künzel R, Levenhagen RS, Herdade SB, Terini RA, Costa PR. X-ray spectroscopy applied to radiation shielding calculation in mammography. Med Phys 2008; 35:3539-45. [DOI: 10.1118/1.2953566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Costa PR, Nersissian DY, Salvador FC, Rio PB, Caldas LVE. Generation of calibrated tungsten target x-ray spectra: modified TBC model. HEALTH PHYSICS 2007; 92:24-32. [PMID: 17164596 DOI: 10.1097/01.hp.0000231565.66004.f9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In spite of the recent advances in the experimental detection of x-ray spectra, theoretical or semi-empirical approaches for determining realistic x-ray spectra in the range of diagnostic energies are important tools for planning experiments, estimating radiation doses in patients, and formulating radiation shielding models. The TBC model is one of the most useful approaches since it allows for straightforward computer implementation, and it is able to accurately reproduce the spectra generated by tungsten target x-ray tubes. However, as originally presented, the TBC model fails in situations where the determination of x-ray spectra produced by an arbitrary waveform or the calculation of realistic values of air kerma for a specific x-ray system is desired. In the present work, the authors revisited the assumptions used in the original paper published by . They proposed a complementary formulation for taking into account the waveform and the representation of the calculated spectra in a dosimetric quantity. The performance of the proposed model was evaluated by comparing values of air kerma and first and second half value layers from calculated and measured spectra by using different voltages and filtrations. For the output, the difference between experimental and calculated data was better then 5.2%. First and second half value layers presented differences of 23.8% and 25.5% in the worst case. The performance of the model in accurately calculating these data was better for lower voltage values. Comparisons were also performed with spectral data measured using a CZT detector. Another test was performed by the evaluation of the model when considering a waveform distinct of a constant potential. In all cases the model results can be considered as a good representation of the measured data. The results from the modifications to the TBC model introduced in the present work reinforce the value of the TBC model for application of quantitative evaluations in radiation physics.
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Affiliation(s)
- Paulo R Costa
- Instituto de Eletrotécnica e Energia/Universidade de São Paulo, Brazil.
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Künzel R, Herdade SB, Costa PR, Terini RA, Levenhagen RS. Ambient dose equivalent and effective dose from scattered x-ray spectra in mammography for Mo/Mo, Mo/Rh and W/Rh anode/filter combinations. Phys Med Biol 2006; 51:2077-91. [PMID: 16585846 DOI: 10.1088/0031-9155/51/8/008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this study, scattered x-ray distributions were produced by irradiating a tissue equivalent phantom under clinical mammographic conditions by using Mo/Mo, Mo/Rh and W/Rh anode/filter combinations, for 25 and 30 kV tube voltages. Energy spectra of the scattered x-rays have been measured with a Cd(0.9)Zn(0.1)Te (CZT) detector for scattering angles between 30 degrees and 165 degrees . Measurement and correction processes have been evaluated through the comparison between the values of the half-value layer (HVL) and air kerma calculated from the corrected spectra and measured with an ionization chamber in a nonclinical x-ray system with a W/Mo anode/filter combination. The shape of the corrected x-ray spectra measured in the nonclinical system was also compared with those calculated using semi-empirical models published in the literature. Scattered x-ray spectra measured in the clinical x-ray system have been characterized through the calculation of HVL and mean photon energy. Values of the air kerma, ambient dose equivalent and effective dose have been evaluated through the corrected x-ray spectra. Mean conversion coefficients relating the air kerma to the ambient dose equivalent and to the effective dose from the scattered beams for Mo/Mo, Mo/Rh and W/Rh anode/filter combinations were also evaluated. Results show that for the scattered radiation beams the ambient dose equivalent provides an overestimate of the effective dose by a factor of about 5 in the mammography energy range. These results can be used in the control of the dose limits around a clinical unit and in the calculation of more realistic protective shielding barriers in mammography.
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Affiliation(s)
- R Künzel
- Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, Cidade Universitária, CEP 05508-900, São Paulo, Brazil.
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Krmar M, Shukla S, Ganezer K. Some aspects involving the use of CdTe for finding end-point energies in diagnostic radiology. Appl Radiat Isot 2005; 64:584-7. [PMID: 16376090 DOI: 10.1016/j.apradiso.2005.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 11/15/2005] [Accepted: 11/16/2005] [Indexed: 10/25/2022]
Abstract
We have considered the use of CdTe detectors and commercially available spectroscopy systems for the determination of the end-point energies of diagnostic X-ray devices. A simple technique based upon filtered spectra and simple fitting procedures was used to deduce end-point energies. We observed some unexpected detector-related effects such as significant shifts in the energy calibration at high count rates. When CdTe detectors operate at high counting rates drifts in the DC level, associated with collection rates of the positive charge (holes) can yield a corresponding shift in the spectrum towards lower energies. Only for relatively low counting rates and long detection periods, in excess of 10 min, can end-point energies be obtained with CdTe that reach levels of precision found in recent protocols. High rates also decrease energy resolution and lower the accuracy of recalibrations using characteristic X-rays from the target.
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Affiliation(s)
- M Krmar
- Department of Physics, California State University Dominguez Hills, Carson, CA 90747, USA.
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