Comparison of Different Body Size Parameters for Individual Dose Adaptation in Body CT of Adults

Menke, Jan

doi:10.1148/radiol.2362041327

Cited by 152 publications

(99 citation statements)

References 24 publications

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“…The optimal radiation dose will depend on patient size and a large correlation between patient size and absorbed radiation dose, also achievable in a thoracic CT examination. 20 We cannot see that this has been initiated in the RP-CT scans.…”

Section: Discussionmentioning

confidence: 99%

Radiation dose differences between thoracic radiotherapy planning CT and thoracic diagnostic CT scans

et al. 2016

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Purpose: To compare the absorbed dose from computed tomography (CT) in radiotherapy planning (RP-CT) against those from diagnostic CT (DG-CT) examinations and to explore the possible reasons for any dose differences.Method: Two groups of patients underwent CT-scans of the thorax with either DG-CT (n=55) or RP-CT (n=55). Patients from each group had similar weight and body mass index (BMI) and were divided into low (<25) and high BMI (>25). Parameters including CTDIvol, DLP and scan-length were compared. Results:The mean CTDIvol and DLP values from RP-CT (38.1 mGy, 1472 mGy·cm) are approximately four times higher than for DG-CT (9.63 mGy, 376.5 mGy·cm). For low BMI group, the CTDIvol in the RP-CT scans (36.4 mGy) is 6.3 times higher than the one in the DG-CT scans (5.8 mGy). For high BMI group, the CTDIvol in the RP-CT (39.6 mGy) is 2.5 times higher than the one in the DG-CT scans (15.8 mGy). In the DG-CT scans a strong negative linear correlation between noise index (NI) and mean CTDIvol was observed (r =-0.954, p=0.004); the higher NI, the lower CTDIvol. This was not the case in the RP-DG scans. Conclusion:The absorbed radiation dose is significantly higher and less BMI dependent for RP-CT scans compared to DG-CT. Image quality requirements of the examinations should be researched to ensure that radiation doses are not unnecessarily high.

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Section: Discussionmentioning

confidence: 99%

Radiation dose differences between thoracic radiotherapy planning CT and thoracic diagnostic CT scans

et al. 2016

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“…Patient age may provide a way to adjust dose measurements in children but does not account for variations in body habitus and does not address dose normalization in small adults. Although height and weight information provide information on body habitus [7], a nomogram is required to translate this information into an equivalent body size; furthermore, there is evidence to suggest that direct measurements of body size are more suitable for dose correction [8,9].…”

Section: Discussionmentioning

confidence: 99%

Automated Estimation of Abdominal Effective Diameter for Body Size Normalization of CT Dose

Cheng

2012

J Digit Imaging

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Most CT dose data aggregation methods do not currently adjust dose values for patient size. This work proposes a simple heuristic for reliably computing an effective diameter of a patient from an abdominal CT image. Evaluation of this method on 106 patients scanned on Philips Brilliance 64 and Brilliance Big Bore scanners demonstrates close correspondence between computed and manually measured patient effective diameters, with a mean absolute error of 1.0 cm (error range +2.2 to −0.4 cm). This level of correspondence was also demonstrated for 60 patients on Siemens, General Electric, and Toshiba scanners. A calculated effective diameter in the middle slice of an abdominal CT study was found to be a close approximation of the mean calculated effective diameter for the study, with a mean absolute error of approximately 1.0 cm (error range +3.5 to −2.2 cm). Furthermore, the mean absolute error for an adjusted mean volume computed tomography dose index (CTDI vol ) using a mid-study calculated effective diameter, versus a mean per-slice adjusted CTDI vol based on the calculated effective diameter of each slice, was 0.59 mGy (error range 1.64 to −3.12 mGy). These results are used to calculate approximate normalized dose length product values in an abdominal CT dose database of 12,506 studies.

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“…Acquisitions were performed without automated exposure control (AEC) devices because these systems were not available on our scanners at the time of enrolment. We did not use weight-specific tube current products since the relationship between body size parameters for individual dose adaptation in body CT of adults had not been implemented in our clinical routine at that time [17]. None of the patients received oral, rectal or IV contrast material, such protocol yielding high diagnostic performance even for alternative diseases as compared with enhanced CT [16,[18][19][20].…”

Section: Ct Examinationsmentioning

confidence: 99%

Optimisedz-axis coverage at multidetector-row CT in adults suspected of acute appendicitis

Brassart

Winant²,

Tack³

et al. 2013

BJR

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Objective: To compare diagnostic performances of two reduced z-axis coverages to full coverage of the abdomen and pelvis for the diagnosis of acute appendicitis and alternative diseases at unenhanced CT. Methods: This study included 152 adults suspected of appendicitis who were enrolled in two ethical committeeapproved previous prospective trials. Based on scans covering the entire abdomen and pelvis (set L), two additional sets of images were generated, each with reduced z-axis coverages: (1) from the top of the iliac crests to the pubis (set S) and (2) from the diaphragmatic crus to the pubis (set M). Two readers independently coded the visualisation of the appendix, measured its diameter and proposed a diagnosis (appendicitis or alternative). Final diagnosis was based on surgical findings or clinical follow-up. Fisher exact and McNemar tests and logistic regression were used.Results: 46 patients had a definite diagnosis of appendicitis and 53 of alternative diseases. The frequency of appendix visualisation was lower for set S than set L for both readers (89% and 84% vs 95% and 91% by Readers A and B, respectively; p50.021 and 0.022). The probability of giving a correct diagnosis was lower for set S (68%) than set L (78%; odds ratio, 0.611; p50.008) for both readers, without significant difference between sets L and M (77%, p50.771); z-axis coverage being reduced by 25% for set M. Conclusion: Coverage from diaphragmatic crus to pubis, but not focused on pelvis only, can be recommended in adults suspected of appendicitis. Advances in knowledge: In suspected appendicitis, CT-coverage can be reduced from diaphragmatic crus to pubis.

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Comparison of Different Body Size Parameters for Individual Dose Adaptation in Body CT of Adults

Abstract: Body weight and circumference enable suitable estimates for individual dose adaptation in body CT of adults if automated dose adaptation is not available.

Cited by 152 publications

References 24 publications

Radiation dose differences between thoracic radiotherapy planning CT and thoracic diagnostic CT scans

Radiation dose differences between thoracic radiotherapy planning CT and thoracic diagnostic CT scans

Automated Estimation of Abdominal Effective Diameter for Body Size Normalization of CT Dose

Optimisedz-axis coverage at multidetector-row CT in adults suspected of acute appendicitis

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