Relationships between patient size, dose and image noise under automatic tube current modulation systems

Sookpeng, Supawitoo; Martin, C J; Gentle, David J; Lopez-Gonzalez, M. Rosario

doi:10.1088/0952-4746/34/1/103

Cited by 31 publications

(21 citation statements)

References 22 publications

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“…Other systems use comparisons with a reference image or reference mAs, thus allowing a higher level of noise for larger patients (Siemens and Philips). The images from larger patients have better separation of organs and other structures due to interposed fatty tissue, so a higher noise level can be tolerated without impairing diagnosis (Sookpeng et al., 2014; Martin and Sookpeng, 2016). (326) Most scanners use the x-ray attenuation of the localiser radiograph for tube current modulation planning.…”

Section: Application Of Drls In Clinical Practicementioning

confidence: 99%

“…This may be done by taking data for different weight groupings or through the fit of an exponential equation to DLP vs weight data (Järvinen et al., 2015). Alternatively, the patient diameter or the cross-sectional area, either of which can be measured from the scanner display, may be recorded and used to group patients (Sookpeng et al., 2014). If data are recorded in an RIS or other patient dose management system, so that results for large numbers of patients are available, then the first and third quartiles may be recorded as well as the median value (Martin, 2016).…”

Section: Application Of Drls In Clinical Practicementioning

confidence: 99%

See 1 more Smart Citation

ICRP Publication 135: Diagnostic Reference Levels in Medical Imaging

Vañó¹,

Miller²,

Martin³

et al. 2017

Ann ICRP

622

383

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The International Commission on Radiological Protection (ICRP) first introduced the term ‘diagnostic reference level’ (DRL) in 1996 in Publication 73. The concept was subsequently developed further, and practical guidance was provided in 2001. The DRL has been proven to be an effective tool that aids in optimisation of protection in the medical exposure of patients for diagnostic and interventional procedures. However, with time, it has become evident that additional advice is needed. There are issues related to definitions of the terms used in previous guidance, determination of the values for DRLs, the appropriate interval for re-evaluating and updating these values, appropriate use of DRLs in clinical practice, methods for practical application of DRLs, and application of the DRL concept to newer imaging technologies. This publication is intended as a further source of information and guidance on these issues. Some terminology has been clarified. In addition, this publication recommends quantities for use as DRLs for various imaging modalities, and provides information on the use of DRLs for interventional procedures and in paediatric imaging. It suggests modifications in the conduct of DRL surveys that take advantage of automated reporting of radiation-dose-related quantities, and highlights the importance of including information on DRLs in training programmes for healthcare workers. The target audience for this publication is national, regional, and local authorities; professional societies; and facilities that use ionising radiation for medical purposes, and responsible staff within these facilities. A full set of the Commission’s recommendations is provided.

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Section: Application Of Drls In Clinical Practicementioning

confidence: 99%

Section: Application Of Drls In Clinical Practicementioning

confidence: 99%

ICRP Publication 135: Diagnostic Reference Levels in Medical Imaging

Vañó¹,

Miller²,

Martin³

et al. 2017

Ann ICRP

622

383

View full text Add to dashboard Cite

show abstract

“…The reference values depend on specific detector configuration, scanning geometry, and beam filtration of different scanner models and manufacturers [47]. Table 1 shows the latest modulation software details of various manufacturers [31,[47][48][49][50][51]. Although TCM is developed for dose reduction, in some situations such as the use of thin slice, low pitch, and short scan time, the dose might increase unexpectedly for maintaining the target image quality (offsetting the negative effect on quality induced by these settings) [21,31,37,52].…”

Section: Tube Currentmentioning

confidence: 99%

Pediatric Computed Tomography Dose Optimization Strategies: A Literature Review

Mahrooqi

Sun

2015

Journal of Medical Imaging and Radiation Sciences

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Introduction: Computed tomography (CT) dose optimization is an important issue in radiography because CT is the largest contributor to medical radiation dose and its use is increasing. However, CT dose optimization for pediatric patients could be more challenging than their adult counterparts. The purpose of this literature review was to identify and discuss the current pediatric CT dose saving techniques. Optimized pediatric protocols were also proposed.Methods: A comprehensive literature search was conducted using the Medline, ProQuest Health and Medical Complete, PubMed, ScienceDirect, Scopus, Springer Link, and Web of Science databases and the keywords CT, pediatric, optimization, protocol, and radiation dose to identify articles focusing on pediatric CT dose optimization strategies published between 2004 and 2014.Results and Summary: Seventy-seven articles were identified in the literature search. Strategies for optimizing a range of scan parameters and technical considerations including tube voltage and current, iterative reconstruction, diagnostic reference levels, bowtie filters, scout view, pitch, scan collimation and time, overscanning, and overbeaming for pediatric patients with different ages and body sizes and compositions were discussed. An example of optimized pediatric protocols specific to age and body size for the 64-slice CT scanners was devised. It is expected that this example could provide medical radiation technologists, radiologists, and medical physicists with ideas to optimize their pediatric protocols.

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“…To reduce the patient dose without compromising image quality, automatic tube current modulation (ATCM) has been implemented on commercial systems of fan-beam computed tomography (FBCT). 15 – 18 The first requirement for the operation of ATCM is the determination of patient attenuation, and this is primarily obtained from the scan projection radiograph (SPR). The methods of ATCM operation are different in CT scanners from different manufacturers.…”

Section: Introductionmentioning

confidence: 99%

A Projection Quality-Driven Tube Current Modulation Method in Cone-Beam CT for IGRT: Proof of Concept

Men

Dai

2017

Technol Cancer Res Treat

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Purpose:To develop a projection quality-driven tube current modulation method in cone-beam computed tomography for image-guided radiotherapy based on the prior attenuation information obtained by the planning computed tomography and then evaluate its effect on a reduction in the imaging dose.Materials and Methods:The QCKV-1 phantom with different thicknesses (0-400 mm) of solid water upon it was used to simulate different attenuation (μ). Projections were acquired with a series of tube current–exposure time product (mAs) settings, and a 2-dimensional contrast to noise ratio was analyzed for each projection to create a lookup table of mAs versus 2-dimensional contrast to noise ratio, μ. Before a patient underwent computed tomography, the maximum attenuation μmaxθ within the 95% range of each projection angle (θ) was estimated according to the planning computed tomography images. Then, a desired 2-dimensional contrast to noise ratio value was selected, and the mAs setting at θ was calculated with the lookup table of mAs versus 2-dimensional contrast to noise ratio,μmaxθ. Three-dimensional cone-beam computed tomography images were reconstructed using the projections acquired with the selected mAs. The imaging dose was evaluated with a polymethyl methacrylate dosimetry phantom in terms of volume computed tomography dose index. Image quality was analyzed using a Catphan 503 phantom with an oval body annulus and a pelvis phantom.Results:For the Catphan 503 phantom, the cone-beam computed tomography image obtained by the projection quality-driven tube current modulation method had a similar quality to that of conventional cone-beam computed tomography . However, the proposed method could reduce the imaging dose by 16% to 33% to achieve an equivalent contrast to noise ratio value. For the pelvis phantom, the structural similarity index was 0.992 with a dose reduction of 39.7% for the projection quality-driven tube current modulation method.Conclusions:The proposed method could reduce the additional dose to the patient while not degrading the image quality for cone-beam computed tomography. The projection quality-driven tube current modulation method could be especially beneficial to patients who undergo cone-beam computed tomography frequently during a treatment course.

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Relationships between patient size, dose and image noise under automatic tube current modulation systems

Cited by 31 publications

References 22 publications

ICRP Publication 135: Diagnostic Reference Levels in Medical Imaging

ICRP Publication 135: Diagnostic Reference Levels in Medical Imaging

Pediatric Computed Tomography Dose Optimization Strategies: A Literature Review

A Projection Quality-Driven Tube Current Modulation Method in Cone-Beam CT for IGRT: Proof of Concept

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