Strategies for Reducing Radiation Dose in CT

McCollough, Cynthia H.; Primak, Andrew N.; Braun, Natalie N.; Kofler, James M.; Yu, Lifeng; Christner, Jodie A.

doi:10.1016/j.rcl.2008.10.006

Cited by 698 publications

(453 citation statements)

References 67 publications

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“…There is a well‐recognized tradeoff between image quality and radiation dose in CT imaging 21, 22, 23, 24, 25, 26, 27. In our department, the tube current of routine MDCT body scans is modulated automatically by the AEC system to achieve consistent image quality for different patient sizes or body parts.…”

Section: Methodsmentioning

confidence: 99%

Optimizing the target detectability of cone beam CT performed in image‐guided radiation therapy for patients of different body sizes

Yang

Ruan

et al. 2018

J Applied Clin Med Phys

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PurposeThe target detectability of cone beam computed tomography (CBCT) performed in image‐guided radiation therapy (IGRT) was investigated to achieve sufficient image quality for patient positioning over a course of treatment session while maintaining radiation exposure from CBCT imaging as low as reasonably achievable (ALARA).MethodsBody CBCT scans operated in half‐fan mode were acquired with three different protocols: CBCTlowD, CBCTmidD, and CBCThighD, which resulted in weighted CT dose index (CTDIw) of 0.36, 1.43, and 2.78 cGy, respectively. An electron density phantom that is 18 cm in diameter was covered by four layers of 2.5‐cm‐thick bolus to simulate patients of different body sizes. Multivariate analysis was used to examine the impact of body size, radiation exposure, and tissue type on the target detectability of CBCT imaging, quantified as contrast‐to‐noise ratio (CNR).ResultsCBCTmidD allows sufficient target detection of adipose, breast, muscle, liver in a background of water for normal‐weight adults with cross‐sectional diameter less than 28 cm, while CBCThighD is suitable for adult patients with larger body sizes or body mass index over 25 kg/m2. Once the cross‐sectional diameter of adult patients is larger than 35 cm, the CTDIw of CBCT scans should be higher than 2.78 cGy to achieve required CNR. As for pediatric and adolescent patients with cross‐sectional diameter less than 25 cm, CBCTlowD is able to produce images with sufficient target detection.ConclusionThe target detectability of soft tissues in default CBCT scans may not be sufficient for overweight or obese adults. Contrary, pediatric and adolescent patients would receive unnecessarily high radiation exposure from default CBCT scans. Therefore, the selection of acquisition parameters for CBCT scans optimized according to patient body size was proposed to ensure sufficient image quality for daily patient positioning in radiation therapy while achieving the ALARA principle.

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Section: Methodsmentioning

confidence: 99%

Optimizing the target detectability of cone beam CT performed in image‐guided radiation therapy for patients of different body sizes

Yang

Ruan

et al. 2018

J Applied Clin Med Phys

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“…The tube voltage was set at 120 kV, and the target noise for the tube current selection was set at 25 HU. The effective radiation dose was estimated from the dose length product multiplied by a conversion coefficient for the chest (0.014 mSv/mGy/cm) as proposed by the European Working Group for Guidelines on Quality Criteria in CT (11).…”

Section: Cctamentioning

confidence: 99%

A New Contrast Enhancement Protocol for Subtraction Coronary Computed Tomography Requiring a Short Breath-Holding Time

et al. 2017

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Rationale and Objectives:We have developed a new contrast enhancement protocol for subtraction coronary computed tomography (SCCTA) requiring a short breath-holding time. In the protocol, test and main boluses were sequentially and automatically injected, and correct timings for pre-contrast and contrast-enhanced scans for main bolus were automatically determined only by the test bolus tracking. Combined with a fixed short main bolus injection for 7 seconds, the breath-holding time was shortened as possible. The purpose of this study was to evaluate whether use of this new protocol produced adequate quality images, taking into account calcified lesions and in-stent lumens.Materials and Methods: Patients (n = 127) with calcium scores of >400 Agatston units or a history of stent placement were enrolled. Breath-holding times were recorded, and image quality was visually evaluated by two observers.Results: The mean ± standard deviation breath-holding time was 13.2 ± 0.6 seconds. The mean ± SD computed tomography (CT) number of coronary arteries for the pre-contrast scan was sufficiently low [99.2 ± 32.2 Hounsfield units (HU)] and, simultaneously, that for SCCTA was 367.0 ± 77.2 HU. The rate of segments evaluated as unreadable was sufficiently low (3.8%).Conclusions: Use of the SCCTA protocol was efficient and allowed for a shorter breath-holding time and adequate diagnostic accuracy of SCCTA images, including images of calcified and stent implantation segments.

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“…In diagnostic radiology, the epidemiological risks associated with the radiation dose of diagnostic imaging have been repeatedly reported as an increasing public threat [5][6][7]; hence a lot of efforts have been made to optimize the radiation doses especially for the CT scan, which accounts for the largest portion of medical exposure today [8][9][10]. Approaches like the use of bowtie filter and automated exposure control are now established practices in diagnostic CT. More recently, the 'Image Gently' [11] and 'Image Wisely' [12] campaigns have been initiated to increase awareness of the opportunities to lower radiation doses in the imaging of children and adults.…”

Section: Personalized Imaging In Igrtmentioning

confidence: 99%