Tin-filtered 100 kV Ultra-low-dose Abdominal CT for Calculi Detection in the Urinary Tract: A Comparative Study of 510 Cases

Kunz, Andreas Steven; Grunz, Jan-Peter; Halt, Daniel; Kalogirou, Charis; Luetkens, Karsten Sebastian; Patzer, Theresa Sophie; Christner, Sara Aniki; Sauer, Stephanie; Bley, Thorsten Alexander; Huflage, Henner

doi:10.1016/j.acra.2022.07.013

Cited by 8 publications

(5 citation statements)

References 26 publications

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“…Dual-energy computed tomography (DECT) has been established in an increasing number of applications for multiple body regions in recent years [1][2][3][4][5][6][7]. However, DECT can result in longer reading times for radiologists due to increased information content [8].…”

Section: Introductionmentioning

confidence: 99%

Obesity-Related Pitfalls of Virtual versus True Non-Contrast Imaging—An Intraindividual Comparison in 253 Oncologic Patients

et al. 2023

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Objectives: Dual-source dual-energy CT (DECT) facilitates reconstruction of virtual non-contrast images from contrast-enhanced scans within a limited field of view. This study evaluates the replacement of true non-contrast acquisition with virtual non-contrast reconstructions and investigates the limitations of dual-source DECT in obese patients. Materials and Methods: A total of 253 oncologic patients (153 women; age 64.5 ± 16.2 years; BMI 26.6 ± 5.1 kg/m2) received both multi-phase single-energy CT (SECT) and DECT in sequential staging examinations with a third-generation dual-source scanner. Patients were allocated to one of three BMI clusters: non-obese: <25 kg/m2 (n = 110), pre-obese: 25–29.9 kg/m2 (n = 73), and obese: >30 kg/m2 (n = 70). Radiation dose and image quality were compared for each scan. DECT examinations were evaluated regarding liver coverage within the dual-energy field of view. Results: While arterial contrast phases in DECT were associated with a higher CTDIvol than in SECT (11.1 vs. 8.1 mGy; p < 0.001), replacement of true with virtual non-contrast imaging resulted in a considerably lower overall dose-length product (312.6 vs. 475.3 mGy·cm; p < 0.001). The proportion of DLP variance predictable from patient BMI was substantial in DECT (R2 = 0.738) and SECT (R2 = 0.620); however, DLP of SECT showed a stronger increase in obese patients (p < 0.001). Incomplete coverage of the liver within the dual-energy field of view was most common in the obese subgroup (17.1%) compared with non-obese (0%) and pre-obese patients (4.1%). Conclusion: DECT facilitates a 30.8% dose reduction over SECT in abdominal oncologic staging examinations. Employing dual-source scanner architecture, the risk for incomplete liver coverage increases in obese patients.

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Section: Introductionmentioning

confidence: 99%

Obesity-Related Pitfalls of Virtual versus True Non-Contrast Imaging—An Intraindividual Comparison in 253 Oncologic Patients

et al. 2023

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“…Although effective dose was investigated in several tin filter studies, it was calculated by multiplying the DLP using a constant dose conversion factor, regardless of the beam quality. More commonly, dose reduction from tin filter is quantified using the scanner CTDI vol or DLP as a surrogate for patient dose or risk 8–14 . While these approaches may be helpful in approximating dose reduction, a more accurate assessment of the dose reduction potential from tin filtration should come from studying its impact on patient organ dose.…”

Section: Introductionmentioning

confidence: 99%

“…Among the recent development of CT technologies, tin spectral filtration has shown potential in radiation dose reduction while maintaining image quality for noncontrast enhanced CT scans. [8][9][10][11][12][13][14] This is applicable to LCS and CTC, which do not require the use of contrast agents due to the inherently high-contrast differential between air and the anatomy of interest (i.e., the pulmonary nodules in the lungs or the colorectal polyps of an CO 2 -insufflated colon). Given this nature, tin filtration is well-suited for these procedures because it removes low-energy X-rays that are less important for image contrast in unenhanced CT.…”

Section: Introductionmentioning

confidence: 99%

“…More commonly, dose reduction from tin filter is quantified using the scanner CTDI vol or DLP as a surrogate for patient dose or risk. [8][9][10][11][12][13][14] While these approaches may be helpful in approximating dose reduction, a more accurate assessment of the dose reduction potential from tin filtration should come from studying its impact on patient organ dose. The goal of this study was to evaluate the effect of tin filtration on patient organ dose and the effective dose calculated from organ dose.…”

Section: Introductionmentioning

confidence: 99%

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Effect of tin spectral filtration on organ and effective dose in CT colonography and CT lung cancer screening

Fong,

Herts,

Primak

et al. 2023

Medical Physics

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BackgroundStudies of tin spectral filtration have demonstrated potential in reducing radiation dose while maintaining image quality for unenhanced computed tomography (CT) scans. The extent of dose reduction, however, was commonly measured using the change in the scanner's reported CTDIvol. This method does not account for how tin filtration affects patient organ and effective dose.PurposeTo investigate the effect of tin filtration on patient organ and effective dose for CT Lung Cancer Screening (LCS) and CT Colonography (CTC).MethodsA previously‐developed Monte Carlo program was adapted to model a 96‐row CT scanner (Somatom Force, Siemens Healthineers) with tin filtration capabilities at 100 kV (100Sn) and 150 kV (150Sn). The program was then validated using experimental CTDIvol measurements at all available kV (70–150 kV) and tin‐filtered kV options (100Sn and 150Sn). After validation, the program simulated LCS scans of the chest and CTC scan of the abdomen‐pelvis for a population of 53 computational patient models from the extended cardiac‐torso family. Each scan was performed using three different spectra: 120 kV, 100Sn, and 150Sn. CTDIvol‐normalized organ doses and DLP‐normalized effective doses, commonly referred to as dose conversion factors, were compared between the different spectra.ResultsFor all LCS and CTC scans, CTDIvol‐normalized organ doses and DLP‐normalized effective doses increased with increasing beam hardness (120 kV, 100Sn, 150 Sn). For LCS, relative for 120 kV, conversion factors for 100Sn produced a median increase in effective dose of 9%, with organ dose increases of 8% to lung, 5% to breast, 15% to thyroid, and 3% to skin. Conversion factors for 150Sn produced a median increase in effective dose of 20%, with organ dose increases of 16%, 18%, 26%, and 12% to these same organs, respectively. For CTC, relative for 120 kV, conversion factors for 100Sn produced a median increase in effective dose of 12%, with organ dose increases of 9% to colon, 10% to liver, 11% to stomach, and 4% to skin. Conversion factors for 150Sn produced a median increase in effective dose of 21%, with organ dose increases of 16%, 17%, 19%, and 10% to these same organs, respectively.ConclusionsResults show that dose conversion factors are greater when using tin filtration and should be considered when evaluating tin's potential for dose reduction.

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“…In recent years, spectral shaping via tin prefiltration has gained increasing recognition in CT research, albeit primarily focused on the paranasal sinus, lung and skeletal system [1][2][3][4][5][6][7]. With regard to abdominal imaging, the use of tin filters is still less common, although studies employing energy-integrating-detector CT systems have previously shown substantial effects here, too [7][8][9][10]. Latest investigations with first-generation photoncounting detector CT (PCD-CT) systems suggest potential for further dose reduction in various imaging tasks [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Potential of Unenhanced Ultra-Low-Dose Abdominal Photon-Counting CT with Tin Filtration: A Cadaveric Study

et al. 2023

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Objectives: This study investigated the feasibility and image quality of ultra-low-dose unenhanced abdominal CT using photon-counting detector technology and tin prefiltration. Materials and Methods: Employing a first-generation photon-counting CT scanner, eight cadaveric specimens were examined both with tin prefiltration (Sn 100 kVp) and polychromatic (120 kVp) scan protocols matched for radiation dose at three different levels: standard-dose (3 mGy), low-dose (1 mGy) and ultra-low-dose (0.5 mGy). Image quality was evaluated quantitatively by means of contrast-to-noise-ratios (CNR) with regions of interest placed in the renal cortex and subcutaneous fat. Additionally, three independent radiologists performed subjective evaluation of image quality. The intraclass correlation coefficient was calculated as a measure of interrater reliability. Results: Irrespective of scan mode, CNR in the renal cortex decreased with lower radiation dose. Despite similar mean energy of the applied x-ray spectrum, CNR was superior for Sn 100 kVp over 120 kVp at standard-dose (17.75 ± 3.51 vs. 14.13 ± 4.02), low-dose (13.99 ± 2.6 vs. 10.68 ± 2.17) and ultra-low-dose levels (8.88 ± 2.01 vs. 11.06 ± 1.74) (all p ≤ 0.05). Subjective image quality was highest for both standard-dose protocols (score 5; interquartile range 5–5). While no difference was ascertained between Sn 100 kVp and 120 kVp examinations at standard and low-dose levels, the subjective image quality of tin-filtered scans was superior to 120 kVp with ultra-low radiation dose (p < 0.05). An intraclass correlation coefficient of 0.844 (95% confidence interval 0.763–0.906; p < 0.001) indicated good interrater reliability. Conclusions: Photon-counting detector CT permits excellent image quality in unenhanced abdominal CT with very low radiation dose. Employment of tin prefiltration at 100 kVp instead of polychromatic imaging at 120 kVp increases the image quality even further in the ultra-low-dose range of 0.5 mGy.

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Tin-filtered 100 kV Ultra-low-dose Abdominal CT for Calculi Detection in the Urinary Tract: A Comparative Study of 510 Cases

Cited by 8 publications

References 26 publications

Obesity-Related Pitfalls of Virtual versus True Non-Contrast Imaging—An Intraindividual Comparison in 253 Oncologic Patients

Obesity-Related Pitfalls of Virtual versus True Non-Contrast Imaging—An Intraindividual Comparison in 253 Oncologic Patients

Effect of tin spectral filtration on organ and effective dose in CT colonography and CT lung cancer screening

Potential of Unenhanced Ultra-Low-Dose Abdominal Photon-Counting CT with Tin Filtration: A Cadaveric Study

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