Physical evaluation of a new technique for X-ray dose reduction: Measurement of signal-to-noise ratio and modulation transfer function in an animal model

Paech, Andreas; Schulz, Arndt P.; Hahlbrauck, B.; Kiene, J.; Wenzl, M; Jürgens, Ch.

doi:10.1016/j.ejmp.2006.12.002

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…In the case of the slit method, if the dimensions are equal to those of the edge, the quotient of the SNRs oscillates between 0 and a value that is greater than 2 (see equation (20)). As the frequency increases this maximum decreases to 2.…”

Section: Discussionmentioning

confidence: 99%

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SNR of MTF calculations in non wide sense stationary systems

González‐López¹

2019

Biomed. Phys. Eng. Express

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Noise in phantom images is propagated to MTF calculated values, increasing their uncertainty. In this work, the phantom that maximizes the signal to noise ratio (SNR) of the MTF is determined as a function of spatial frequency and noise in the images. New analytic expressions for the SNRs of the MTF are derived, and formerly published ones are modified to take into account that real noise is not wide sense stationary (WSS). Five phantoms are used: slit, wire, edge, bar and star-bar. The SNRs are inversely proportional to the frequency in the slit, wire and edge methods. For the phantoms based in periodic pattern, the SNRs are inversely proportional to the squared root of frequency. In the slit and wire methods, an oscillating factor is also present. The loss of the WSS of noise determines the contribution of quantum noise to the SNR. This contribution is negligible in the slit case and remains unaltered in the wire case. The edge, bar and star-bar represent intermediate cases. Finally, ratios of the SNRs between the different methods are provided. These ratios quantify the relative uncertainty of two methods as a function of frequency, noise and the physical dimensions of the phantoms. In this way, these ratios can be used to determine which method produces the optimal SNR in any situation.

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Section: Discussionmentioning

confidence: 99%

“…The MTF is usually obtained by analysing the frequency contents of the image of a phantom. Phantoms based on pin-holes [2], slits [3][4][5], wires [3,4,[6][7][8], edges [9][10][11][12][13][14][15][16][17] or linear bar patterns [18][19][20] are used for this purpose.…”

Section: Introductionmentioning

confidence: 99%

SNR of MTF calculations in non wide sense stationary systems

González‐López¹

2019

Biomed. Phys. Eng. Express

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“…Processing the images of slits, [1][2][3][4][5] bar patterns [6][7][8][9] and edge objects [10][11][12][13][14][15][16][17][18] are commonly used methods for measuring the MTF. The edge method is the one recommended by the International Electrotechnical Commission.…”

Section: Introductionmentioning

confidence: 99%

Performance of a new star‐bar phantom designed for MTF calculations in x‐ray imaging systems

et al. 2020

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Purpose: A new phantom, designed and manufactured for modulation transfer function (MTF) calculations is presented in this work. The phantom has a star-bar pattern and is manufactured in stainless steel. Modulation transfer function determinations are carried out with the new phantom and with an edge phantom to compare their performance and to compare them with previous theoretical predictions. Methods: The phantoms are imaged in an x-ray imaging system using different beam qualities and different entrance air KERMA. Methods, previously developed for synthetic images and simulations, are adapted to real measurements, solving practical implementation issues. Results: In the case of the star-bar, in order to obtain optimal MTF determinations it is necessary to accurately determine the center of the pattern. Also, to avoid underestimates in MTF calculations, the length in pixels of each of the scanning circumferences must be an integer multiple of the number of cycles in the pattern. Both methods, star-bar and edge, give similar mean values of the MTF in all cases analyzed. Also, the dependence with frequency of the experimental MTF standard deviation (SD) agrees with the theoretical expressions presented in previous works. In this regard, the precision is better for the star-bar method than for the edge and differences in precision between both methods are higher for the lowest beam quality. Conclusions: The star-bar phantom can be used for MTF determinations with the advantage of having an improved precision. However, precision is reduced when the radiation quality increases. This fact suggests that, for the highest beam qualities, materials with an attenuation coefficient greater than that of steel should be used to manufacture the phantom.

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“…In order to obtain good quality examination results while decreasing the size of the absorbed radiation dose, the physical parameters affecting the distribution of the radiation dose should be optimized [7][8][9]. Optimization of the exposure conditions is related to the patient's anatomy and the area of the body to be examined.…”

Section: Introductionmentioning

confidence: 99%

Physical parameters affecting the distribution of X-ray dose during hysterosalpingography

Kasprzyk,

Chmaj-Wierzchowska,

Jurczyk

2020

Clin. Exp. Obstet. Gynecol.

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Objective: Hysterosalpingography (HSG) is based on the administration of a shading agent to the uterine cavity and fallopian tubes using a Schulze apparatus. An X-ray beam (X) is then directed at the abdominal area of the patient and diagnostic images are obtained for evaluation. The radiation beam and its mode of administration have a decisive influence on the radiation dose to which the patient is exposed. The aim of this study was to determine the physical parameters of this exposure in such a way that the dose distribution during the HSG examination was the most beneficial for the patient. Materials and Methods: Measurements to evaluate the effect of exposure parameters on the quality of radiological images obtained during HSG in slim and obese patients were made in 216 repetitions of the standard HSG test. Additional research data was obtained from measurements made in the X-ray laboratory at the Clinical Hospital. Results: The comparison of all measurements made for experimental models simulating a slim and obese patient demonstrated that the dose distribution most advantageous for the patient is obtained for pulsations of an X-ray tube for PPS = 6, regardless of the thickness of the patient. Conclusions: The image quality and size of the radiation dose received during the HSG examination depends on the individual characteristics of the patient. During the measurements performed in order to compare the exposure conditions set by the automatic exposure control (AEC) system and the resulting dose, this study demonstrated that the dose distribution most advantageous for the patients is obtained for pulsations on an X-ray tube for PPS = 6, regardless of the thickness of the patient.

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Physical evaluation of a new technique for X-ray dose reduction: Measurement of signal-to-noise ratio and modulation transfer function in an animal model

Cited by 5 publications

References 8 publications

SNR of MTF calculations in non wide sense stationary systems

SNR of MTF calculations in non wide sense stationary systems

Performance of a new star‐bar phantom designed for MTF calculations in x‐ray imaging systems

Physical parameters affecting the distribution of X-ray dose during hysterosalpingography

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