Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran

Abstract

Objective: The literature has approved that the use of the concept of diagnostic reference level (DRL) as a part of an optimization process could help to reduce patient doses in diagnostic radiology comprising the Computed Tomography (CT) examinations. There are four public/governmental CT centers in the province (Semnan, Iran) and, to our knowledge, after about 12 years since the launch of the first CT scanner in the province there is no dosimetry information on those CT scanners. The aim of this study was to evaluate CT dose indices with the aim of the establishment of the DRL for head, chest, cervical spine, and abdomen-pelvis examinations. Methods: Scan parameters of 381 patients were collected during two months from 4 CT scanners. The CT dose index (CTDI) was measured using a calibrated ionization chamber on two cylindrical poly methyl methacrylate (PMMA) phantoms. For each sequences, weighted CTDI (CTDIw), volumetric CTDI (CTDIv) and dose length product (DLP) were calculated. The 75th percentile was proposed as the criterion for DRL values. Results: Proposed DRL (CTDIw, CTDIv, DLP) for the head, chest, cervical spine, and abdomen-pelvis were (46.1 mGy, 46.1 mGy, 723 mGy × cm), (13.8 mGy, 12.0 mGy, 377 mGy × cm), (40.0 mGy, 40.0 mGy, 572 mGy × cm) and (14.9 mGy, 12.1 mGy, 524 mGy × cm), respectively. Conclusion: Comparison with the others results from the other countries indicates that the head, chest and abdomen-pelvis scans in our region are lower or in the range of the other studies investigated in terms of dose. In the case of cervical spine scanning it’s necessary to review and regulate scan protocols to reach acceptable dose levels.

Computed tomography radiation doses for common computed tomography examinations: a nationwide dose survey in United Arab Emirates

“…A survey of CT dosage in Syria was conducted in 2009 and thus is relatively old with no updates available. Table 5 shows a comparison of the CTDI vol and DLP results with those of Australia (2015), ACR DIR (2016), Japan (2015), the EU (2014), Greece (2014), Egypt (2017), and ICRP (2007) [3,[16][17][18]. The values in this study were approximately lower than and comparable with those reported in other studies.…”

“…Generally, variation in the protocol can affect the radiation dose; therefore, the same scanner might result in doses higher or lower than the DRLs. Similar or higher variation was reported: about 12-fold in the UK and more than 20-fold in the USA, and 2.9- to 10.4-fold variations in the head and abdomen-pelvis examinations [ 17 ]. Foley et al reported variations of up to 89% dose variation using identical scanners in different sites [ 18 ].…”

Diagnostic Reference Level of Radiation Dose and Image Quality among Paediatric CT Examinations in A Tertiary Hospital in Malaysia

“…Both developed and developing countries have established dose survey data as a guideline to develop their own DRL in medical imaging procedures [20][21][22]. A DRL could serve as a good tool in optimizing the radiation doses of CT examinations in pediatric patients and ensuring good image quality [23][24][25]. The Malaysian Health Ministry had established its DRL for radiological procedures in its Medical Radiation Exposure Report in May 2013.…”

A review on chest CT scanning parameters implemented in COVID-19 patients: bringing low-dose CT protocols into play

“…The primary dose descriptor for CT is computed tomography dose index (CTDI). The CTDI describes the summation of all dose contributions along the z -axis [ 33 , 34 ]: …”