Comparison of Tin Filter–Based Spectral Shaping CT and Low-Dose Protocol for Detection of Urinary Calculi

Mozaffary, Amirhossein; Trabzonlu, Tugce Agirlar; Kim, Donald; Yaghmai, Vahid

doi:10.2214/ajr.18.20154

Cited by 29 publications

(41 citation statements)

References 22 publications

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“…stones (27,28). With the tin filter, a decrease in radiationdose overlap of the two applied energy spectra occurs allowing for better tissue discrimination (29,30).…”

Section: Discussionmentioning

confidence: 99%

Influence of Radiation Dose, Photon Energy, and Reconstruction Kernel on rho/z Analysis in Spectral Computer Tomography: A Phantom Study

Chatzaraki

Bolsi

Kubik‐Huch

et al. 2022

In Vivo

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Background/Aim: The effective atomic number (Z eff ) and electron density relative to water (ρ e or Rho) of elements can be derived in dual-energy computed tomography (DECT). The aim of this phantom study was to investigate the effect of different photon energies, radiation doses, and reconstruction kernels on Z eff and Rho measured in DECT. Materials and Methods: An anthropomorphic head phantom including five probes of known composition was scanned under three tube-voltage combinations in DECT: Sn140/100 kV, 140/80 kV and Sn140/80 kV with incremented radiation doses. Raw data were reconstructed with four reconstruction kernels (I30, I40, I50, and I70). Rho and Z eff were measured for each probe for all possible combinations of scan and reconstruction parameters. Results: DECT-based Rho and Z eff closely approached the reference values with a mean and maximum error of 1.7% and 6.8%, respectively. Rho was lower for 140/80 kV compared with Sn140/100 kV and Sn140/80 kV with differences being 0.009. Z eff differed among all tube voltages with the most prominent difference being 0.28 between 140/80 kV and Sn140/100 kV. Z eff was lower in I70 compared with those of I30 and I40 with a difference of 0.07. Varying radiation dose yielded a variation of 0.0002 in Rho and 0.03 in Z, both considered negligible in practice. Conclusion: DECT comprises a feasible method for the extraction of material-specific information. Slight variations should be taken into account when different radiation doses, photon energies, and kernels are applied; however, they are considered small and in practice not crucial for an effective tissue differentiation.

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“…stones (27,28). With the tin filter, a decrease in radiationdose overlap of the two applied energy spectra occurs allowing for better tissue discrimination (29,30).…”

Section: Discussionmentioning

confidence: 99%

Influence of Radiation Dose, Photon Energy, and Reconstruction Kernel on rho/z Analysis in Spectral Computer Tomography: A Phantom Study

Chatzaraki

Bolsi

Kubik‐Huch

et al. 2022

In Vivo

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“…Finally, it should be noted than special low dose protocols for some clinical indication, e.g. renal stone CT [74,75] and pulmonary nodule follow-up CT, should be distinguished from other protocols that share the same anatomic scan region, otherwise they will constantly produce low dose outliers.…”

Section: Data Analysis and Alertsmentioning

confidence: 99%

Radiation dose monitoring in computed tomography: Status, options and limitations

et al. 2020

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In the last few years there has been an increasing interest on radiation dose to patients undergoing various diagnostic or therapeutic procedures with the use of ionizing radiation. Especially for CT examinations and interventional procedures, where it is known that patient doses are much higher than conventional radiography, new norms have been published that require to have appropriate radiation dose indices registered in the patient medical record. Because of these demands, dose monitoring has been recommended and adopted into many clinical practices as a routine procedure for every patient and every examination. Dedicated dose monitoring systems (DMS) that facilitate data collection and processing, statistical comparisons, reporting and management of radiation dose related information have been devised and are being used worldwide. In this review paper, a brief flashback to the reasons that necessitated dose monitoring in radiology will be first presented. Furthermore, since the focus of this manuscript is on CT, the CT dosimetry principles and metrics will be summarized. The limitations of these metrics will be also discussed, so that DMS users are aware of the semantics of the parameters shown in the DMS reports. The operation of DMS systems will be outlined to make users aware of functions, limitations, and available options of DMS systems. Furthermore, the usefulness of DMS systems as an optimization tool will be presented and discussed. Finally, information about the DMS solutions available in the market and relevant links will be presented.

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“…In abdominal scans for urinary stone detection 22% dose reduction was achieved by Dewes et al 6 . Mozaffary et al 7 . found 28% to 66% dose reduction in CT scans for urinary stone disease.…”

Section: Introductionmentioning

confidence: 99%

“…Leyendecker et al 4 were able to achieve 81% dose reduction in contrast-enhanced abdominal CT. Weis et al 5 found 77% dose reduction in pediatric chest CT. In abdominal scans for urinary stone detection 22% dose reduction was achieved by Dewes et al 6 Mozaffary et al 7 found 28% to 66% dose reduction in CT scans for urinary stone disease. All four studies used the Siemens Force system with its 0.6 mm tin filter.…”

Section: Introductionmentioning

confidence: 99%

Dose reduction potential in diagnostic single energy CT through patient‐specific prefilters and a wider range of tube voltages

et al. 2021

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Various studies have demonstrated that additional prefilters and/or reduced tube voltages have the potential to significantly increase the contrastto-noise ratios at unit dose (CNRDs) and thereby to significantly reduce patient dose in clinical CT. An exhaustive analysis, accounting for a wide range of filter thicknesses and a wide range of tube voltages extending beyond the 70 to 150 kV range of today's CT systems, including their specific choice depending on the patient size, is, however, missing. Therefore, this work analyzes the dose reduction potential for patient-specific selectable prefilters combined with a wider range of tube voltages. We do so for soft tissue and iodine contrast in single energy CT. The findings may be helpful to guide further developments of x-ray tubes and automatic filter changers. Methods: CT acquisitions were simulated for different patient sizes (semianthropomorphic phantoms for child, adult, and obese patients), tube voltages (35-150 kV), prefilter materials (tin and copper), and prefilter thicknesses (up to 5 mm). For each acquisition soft tissue and iodine CNRDs were determined. Dose was calculated using Monte Carlo simulations of a computed tomography dose index (CTDI) phantom. CNRD values of acquisitions with different parameters were used to evaluate dose reduction. Results: Dose reduction through patient-specific prefilters depends on patient size and available tube current among others. With an available tube current time product of 1000 mAs dose reductions of 17% for the child, 32% for the adult and 29% for the obese phantom were achieved for soft tissue contrast. For iodine contrast dose reductions were 57%, 49%, and 39% for child, adult, and obese phantoms, respectively. Here, a tube voltage range extended to lower kV is important. Conclusions: Substantial dose reduction can be achieved by utilizing patientspecific prefilters. Tube voltages lower than 70 kV are beneficial for dose reduction with iodine contrast, especially for small patients. The optimal implementation of patient-specific prefilters benefits from higher tube power. Tin prefilters should be available in 0.1 mm steps or lower, copper prefilter in 0.3 mm steps or lower. At least 10 different prefilter thicknesses should be used to cover the dose optima of all investigated patient sizes and contrast mechanisms. In many cases it would be advantageous to adapt the prefilter thickness rather than the tube current to the patient size, that is, to always use the maximum available tube current and to control the exposure by adjusting the thickness of the prefilter.

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Comparison of Tin Filter–Based Spectral Shaping CT and Low-Dose Protocol for Detection of Urinary Calculi

Cited by 29 publications

References 22 publications

Influence of Radiation Dose, Photon Energy, and Reconstruction Kernel on rho/z Analysis in Spectral Computer Tomography: A Phantom Study

Influence of Radiation Dose, Photon Energy, and Reconstruction Kernel on rho/z Analysis in Spectral Computer Tomography: A Phantom Study

Radiation dose monitoring in computed tomography: Status, options and limitations

Dose reduction potential in diagnostic single energy CT through patient‐specific prefilters and a wider range of tube voltages

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