Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages

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Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages. / Sandborg, Michael; Tingberg, Anders; Ullman, Gustaf; Dance, David R.; Carlsson, Gudrun Alm.

In: Medical Physics, Vol. 33, No. 11, 2006, p. 4169-4175.

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Sandborg, Michael ; Tingberg, Anders ; Ullman, Gustaf ; Dance, David R. ; Carlsson, Gudrun Alm. / Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages. In: Medical Physics. 2006 ; Vol. 33, No. 11. pp. 4169-4175.

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TY - JOUR

T1 - Comparison of clinical and physical measures of image quality in chest and pelvis computed radiography at different tube voltages

AU - Sandborg, Michael

AU - Tingberg, Anders

AU - Ullman, Gustaf

AU - Dance, David R.

AU - Carlsson, Gudrun Alm

PY - 2006

Y1 - 2006

N2 - The aim of this work was to study the dependence of image quality in digital chest and pelvis radiography on tube voltage, and to explore correlations between clinical and physical measures of image quality. The effect on image quality of tube voltage in these two examinations was assessed using two methods. The first method relies on radiologists' observations of images of an anthropomorphic phantom, and the second method was based on computer modeling of the imaging system using an anthropomorphic voxel phantom. The tube voltage was varied within a broad range (50-150 kV), including those values typically used with screen-film radiography. The tube charge was altered so that the same effective dose was achieved for each projection. Two x-ray units were employed using a computed radiography (CR) image detector with standard tube filtration and antiscatter device. Clinical image quality was assessed by a group of radiologists using a visual grading analysis (VGA) technique based on the revised CEC image criteria. Physical image quality was derived from a Monte Carlo computer model in terms of the signal-to-noise ratio, SNR, of anatomical structures corresponding to the image criteria. Both the VGAS (visual grading analysis score) and SNR decrease with increasing tube voltage in both chest PA and pelvis AP examinations, indicating superior performance if lower tube voltages are employed. Hence, a positive correlation between clinical and physical measures of image quality was found. The pros and cons of using lower tube voltages with CR digital radiography than typically used in analog screen-film radiography are discussed, as well as the relevance of using VGAS and quantum-noise SNR as measures of image quality in pelvis and chest radiography.

AB - The aim of this work was to study the dependence of image quality in digital chest and pelvis radiography on tube voltage, and to explore correlations between clinical and physical measures of image quality. The effect on image quality of tube voltage in these two examinations was assessed using two methods. The first method relies on radiologists' observations of images of an anthropomorphic phantom, and the second method was based on computer modeling of the imaging system using an anthropomorphic voxel phantom. The tube voltage was varied within a broad range (50-150 kV), including those values typically used with screen-film radiography. The tube charge was altered so that the same effective dose was achieved for each projection. Two x-ray units were employed using a computed radiography (CR) image detector with standard tube filtration and antiscatter device. Clinical image quality was assessed by a group of radiologists using a visual grading analysis (VGA) technique based on the revised CEC image criteria. Physical image quality was derived from a Monte Carlo computer model in terms of the signal-to-noise ratio, SNR, of anatomical structures corresponding to the image criteria. Both the VGAS (visual grading analysis score) and SNR decrease with increasing tube voltage in both chest PA and pelvis AP examinations, indicating superior performance if lower tube voltages are employed. Hence, a positive correlation between clinical and physical measures of image quality was found. The pros and cons of using lower tube voltages with CR digital radiography than typically used in analog screen-film radiography are discussed, as well as the relevance of using VGAS and quantum-noise SNR as measures of image quality in pelvis and chest radiography.

KW - chest radiography

KW - signal-to-noise ratio

KW - visual grading analysis

KW - tube voltage

KW - image quality

KW - effective dose

KW - pelvis radiography

KW - computed

KW - radiography

U2 - 10.1118/1.2362871

DO - 10.1118/1.2362871

M3 - Article

VL - 33

SP - 4169

EP - 4175

JO - Medical Physics

T2 - Medical Physics

JF - Medical Physics

SN - 0094-2405

IS - 11

ER -