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National Survey of Radiation Dose and Image Quality in Adult CT Head Scans in Taiwan.

Lin CJ, Mok GS, Tsai MF, Tsai WT, Yang BH, Tu CY, Wu TH - PLoS ONE (2015)

Bottom Line: SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C.MDCT with higher slice numbers used more tube potential resulting in higher effective doses.Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices.

View Article: PubMed Central - PubMed

Affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.

ABSTRACT

Introduction: The purpose of the present study was to evaluate the influence of different variables on radiation dose and image quality based on a national database.

Materials and methods: Taiwan's Ministry of Health and Welfare requested all radiology departments to complete a questionnaire for each of their CT scanners. Information gathered included all scanning parameters for CT head scans. For the present analysis, CT machines were divided into three subgroups: single slice CT (Group A); multi-detector CT (MDCT) with 2-64 slices (Group B); and MDCT with more than 64 slices (Group C). Correlations between computed tomography dose index (CTDI) and signal-to-noise ratio (SNR) with cumulated tube rotation number (CTW(n)) and cumulated tube rotation time (CTW(s)), and sub group analyses of CTDI and SNR across the three groups were performed.

Results: CTDI values demonstrated a weak correlation (r = 0.33) with CTW(n) in Group A. SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C. MDCT with higher slice numbers used more tube potential resulting in higher effective doses. There were both significantly lower CTDI and SNR values in helical mode than in axial mode in Group B, but not Group C.

Conclusion: CTW(n) and CTW(s) did not influence radiation output. Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices.

No MeSH data available.


Related in: MedlinePlus

The work flow diagram demonstrates how the raw data from the questionnaire was rearranged into the final dataset.
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pone.0131243.g002: The work flow diagram demonstrates how the raw data from the questionnaire was rearranged into the final dataset.

Mentions: For each questionnaire, missing values were left blank while other available data were still used. The questionnaire was considered invalid if values of both CTDI and SNR were missing. Entry values of > 1.5 times the inter-quartile range from the mean were excluded from subsequent analysis. Given the fundamental differences in the hardware design of single slice CT and MDCT, all CT scanners were divided into 3 subgroups: single slice CT(Group A); MDCTs with a detector number <64 (Group B); MDCTs with ≥64 detectors. Subgroup comparisons of CTDI and SNR were also done for different scan modes and between Group B and C. The workflow of the study was summarized in Fig 2.


National Survey of Radiation Dose and Image Quality in Adult CT Head Scans in Taiwan.

Lin CJ, Mok GS, Tsai MF, Tsai WT, Yang BH, Tu CY, Wu TH - PLoS ONE (2015)

The work flow diagram demonstrates how the raw data from the questionnaire was rearranged into the final dataset.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488422&req=5

pone.0131243.g002: The work flow diagram demonstrates how the raw data from the questionnaire was rearranged into the final dataset.
Mentions: For each questionnaire, missing values were left blank while other available data were still used. The questionnaire was considered invalid if values of both CTDI and SNR were missing. Entry values of > 1.5 times the inter-quartile range from the mean were excluded from subsequent analysis. Given the fundamental differences in the hardware design of single slice CT and MDCT, all CT scanners were divided into 3 subgroups: single slice CT(Group A); MDCTs with a detector number <64 (Group B); MDCTs with ≥64 detectors. Subgroup comparisons of CTDI and SNR were also done for different scan modes and between Group B and C. The workflow of the study was summarized in Fig 2.

Bottom Line: SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C.MDCT with higher slice numbers used more tube potential resulting in higher effective doses.Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices.

View Article: PubMed Central - PubMed

Affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.

ABSTRACT

Introduction: The purpose of the present study was to evaluate the influence of different variables on radiation dose and image quality based on a national database.

Materials and methods: Taiwan's Ministry of Health and Welfare requested all radiology departments to complete a questionnaire for each of their CT scanners. Information gathered included all scanning parameters for CT head scans. For the present analysis, CT machines were divided into three subgroups: single slice CT (Group A); multi-detector CT (MDCT) with 2-64 slices (Group B); and MDCT with more than 64 slices (Group C). Correlations between computed tomography dose index (CTDI) and signal-to-noise ratio (SNR) with cumulated tube rotation number (CTW(n)) and cumulated tube rotation time (CTW(s)), and sub group analyses of CTDI and SNR across the three groups were performed.

Results: CTDI values demonstrated a weak correlation (r = 0.33) with CTW(n) in Group A. SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C. MDCT with higher slice numbers used more tube potential resulting in higher effective doses. There were both significantly lower CTDI and SNR values in helical mode than in axial mode in Group B, but not Group C.

Conclusion: CTW(n) and CTW(s) did not influence radiation output. Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices.

No MeSH data available.


Related in: MedlinePlus