统计分析以获得 CT 扫描仪的最佳数量，用于确定国家诊断参考水平的患者剂量调查。

Statistical analysis for obtaining optimum number of CT scanners in patient dose surveys for determining national diagnostic reference levels.

机构信息

Health Physics and Dosimetry Research Laboratory, Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran, Iran.

Department of Radiology, Faculty of Paramedical, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.

出版信息

Eur Radiol. 2019 Jan;29(1):168-175. doi: 10.1007/s00330-018-5547-3. Epub 2018 Jun 28.

DOI:10.1007/s00330-018-5547-3

PMID:29955947

Abstract

OBJECTIVES

To statistically determine an 'optimum number of CT scanners' for obtaining 'diagnostic reference levels' (DRLs) in CT examinations as close as possible to 'ideal DRLs' when all available CT scanners are considered.

METHODS

First, six 'ideal DRLs' (CTDI and DLP) were determined for head, chest and abdomen/pelvis examinations by using patient-dose survey data of 100 CT scanners of different models in Tehran. Then, a 'random sampling method' was applied to different percent fractions of patient dose data of 100 CT scanners. The percent differences (PD) of the DRLs obtained from 'ideal DRLs' and their coefficients of variation (CVs) were calculated. The 'optimum number of CT scanners' determined met those of 'ideal DRL' criteria; i.e. precision (CV ≤ 10%) and accuracy (PD ≤ 10%).

RESULTS

'Optimum number of CT scanners' for determining DRLs as close as possible to 'ideal DRLs', fulfilling the stated criteria, is 43 instead of using 100.

CONCLUSION

'Optimum number of CT scanners' for obtaining DRLs as close as possible to 'ideal DRLs' was determined. This optimum number can be effectively applied in patient-dose survey situations with limited resources in a time- and cost-effective manner.

KEY POINTS

• Ideal DRLs were determined by a CT patient-dose survey applied to available scanners. • 'Optimum number of CT scanners' statistically determined for DRLs is 43%. • Optimum number can be used for DRLs as if 'ideal DRLs' were determined by all scanners.

摘要

目的

通过统计方法确定“最佳 CT 扫描仪数量”，以便在考虑所有可用 CT 扫描仪时，尽可能接近“理想诊断参考水平（DRL）”获得 CT 检查中的 DRL。

方法

首先，通过对德黑兰 100 台不同型号 CT 扫描仪的患者剂量调查数据，确定头、胸和腹部/骨盆检查的 6 个“理想 DRL（CTDI 和 DLP）”。然后，应用“随机抽样法”对 100 台 CT 扫描仪的不同比例的患者剂量数据进行抽样。计算从“理想 DRL”得出的 DRL 的百分差（PD）及其变异系数（CV）。确定的“最佳 CT 扫描仪数量”符合“理想 DRL”标准；即精度（CV≤10%）和准确性（PD≤10%）。