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Multi-detector row CT: radiation dose characteristics.
Radiology. 2003 Mar; 226(3):762-72.R

Abstract

PURPOSE

To determine the dose characteristics of multi-detector row computed tomography (CT) and to provide tabulated dose values and rules of thumb that assist in minimizing the radiation dose at multi-detector row CT.

MATERIALS AND METHODS

Weighted CT dose index (CTDI100w) values were obtained from three multi-detector row CT scanners (LightSpeed; GE Medical Systems, Milwaukee, Wis) for both head and body CT modes by using standard CT-dose phantoms. The CTDI100w was determined as a function of x-ray tube voltage (80, 100, 120, 140 kVp), tube current (range, 50-380 mA), tube rotation time (0.5-4.0 seconds), radiation profile width (RPW) (5, 10, 15, 20 mm), and acquisition mode (helical high-quality and high-speed modes and axial one-, two-, and four-section modes). Statistical regression was performed to characterize the relationships between CTDI100w and various technique factors.

RESULTS

The CTDI100w (milligray) increased linearly with tube current: in head mode, CTDI100w = (0.391 mGy/mA +/- 0.004) x tube current (milliampere) (r2 = 0.999); in body mode, CTDI100w = (0.162 mGy/mA +/- 0.002) x tube current (milliampere) (r2 = 0.999). The CTDI100w increased linearly with rotation time: in head mode, CTDI100w = (34.7 mGy/sec +/- 0.2) x rotation time (seconds) (r2 = 1.0); in body mode, CTDI100w = (13.957 mGy/sec +/- 0.005) x rotation time (seconds) (r2 = 1.0). The relationship of normalized CTDI100w (milligrays per 100 mAs) with tube voltage followed a power law: in head mode, CTDI100w = (0.00016 mGy/100 mAs. kVp +/- 0.00007) x (tube voltage)(2.5+/-0.1) (r2 = 0.997); in body mode, CTDI100w = (0.000012 mGy/100 mAs. kVp +/- 0.000007) x (tube voltage)(2.8+/-0.1) (r2 = 0.996). In all scanning modes, CTDI100w decreased when RPW increased. CTDI100w was 10% higher in head mode and 13% lower in body mode compared with the value suggested by the manufacturer, which is displayed at the scanner console. When deposited power exceeded 24 kW, CTDI100w increased by 10% as a result of use of the large focal spot.

CONCLUSION

The authors provide a set of tables of radiation dose as a function of imaging protocol to facilitate implementation of radiation dose-efficient studies.

Authors+Show Affiliations

Department of Radiology, Perfusion and Physiology Analysis Laboratory, Massachusetts General Hospital, 55 Fruit St, Gray Bldg, Rm B238, Boston, MA 02114, USA. lhamberg@partners.orgNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

12616020

Citation

Hamberg, Leena M., et al. "Multi-detector Row CT: Radiation Dose Characteristics." Radiology, vol. 226, no. 3, 2003, pp. 762-72.
Hamberg LM, Rhea JT, Hunter GJ, et al. Multi-detector row CT: radiation dose characteristics. Radiology. 2003;226(3):762-72.
Hamberg, L. M., Rhea, J. T., Hunter, G. J., & Thrall, J. H. (2003). Multi-detector row CT: radiation dose characteristics. Radiology, 226(3), 762-72.
Hamberg LM, et al. Multi-detector Row CT: Radiation Dose Characteristics. Radiology. 2003;226(3):762-72. PubMed PMID: 12616020.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Multi-detector row CT: radiation dose characteristics. AU - Hamberg,Leena M, AU - Rhea,James T, AU - Hunter,George J, AU - Thrall,James H, PY - 2003/3/5/pubmed PY - 2003/4/11/medline PY - 2003/3/5/entrez SP - 762 EP - 72 JF - Radiology JO - Radiology VL - 226 IS - 3 N2 - PURPOSE: To determine the dose characteristics of multi-detector row computed tomography (CT) and to provide tabulated dose values and rules of thumb that assist in minimizing the radiation dose at multi-detector row CT. MATERIALS AND METHODS: Weighted CT dose index (CTDI100w) values were obtained from three multi-detector row CT scanners (LightSpeed; GE Medical Systems, Milwaukee, Wis) for both head and body CT modes by using standard CT-dose phantoms. The CTDI100w was determined as a function of x-ray tube voltage (80, 100, 120, 140 kVp), tube current (range, 50-380 mA), tube rotation time (0.5-4.0 seconds), radiation profile width (RPW) (5, 10, 15, 20 mm), and acquisition mode (helical high-quality and high-speed modes and axial one-, two-, and four-section modes). Statistical regression was performed to characterize the relationships between CTDI100w and various technique factors. RESULTS: The CTDI100w (milligray) increased linearly with tube current: in head mode, CTDI100w = (0.391 mGy/mA +/- 0.004) x tube current (milliampere) (r2 = 0.999); in body mode, CTDI100w = (0.162 mGy/mA +/- 0.002) x tube current (milliampere) (r2 = 0.999). The CTDI100w increased linearly with rotation time: in head mode, CTDI100w = (34.7 mGy/sec +/- 0.2) x rotation time (seconds) (r2 = 1.0); in body mode, CTDI100w = (13.957 mGy/sec +/- 0.005) x rotation time (seconds) (r2 = 1.0). The relationship of normalized CTDI100w (milligrays per 100 mAs) with tube voltage followed a power law: in head mode, CTDI100w = (0.00016 mGy/100 mAs. kVp +/- 0.00007) x (tube voltage)(2.5+/-0.1) (r2 = 0.997); in body mode, CTDI100w = (0.000012 mGy/100 mAs. kVp +/- 0.000007) x (tube voltage)(2.8+/-0.1) (r2 = 0.996). In all scanning modes, CTDI100w decreased when RPW increased. CTDI100w was 10% higher in head mode and 13% lower in body mode compared with the value suggested by the manufacturer, which is displayed at the scanner console. When deposited power exceeded 24 kW, CTDI100w increased by 10% as a result of use of the large focal spot. CONCLUSION: The authors provide a set of tables of radiation dose as a function of imaging protocol to facilitate implementation of radiation dose-efficient studies. SN - 0033-8419 UR - https://www.unboundmedicine.com/medline/citation/12616020/Multi_detector_row_CT:_radiation_dose_characteristics_ L2 - https://pubs.rsna.org/doi/10.1148/radiol.2263020205?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -