Computed tomography colonography and radiation risk: How low can we go? (original) (raw)
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Journal of Applied Clinical Medical Physics
Objective: To assess the radiation dose and image quality of ultra-low dose (ULD)-CT colonography (CTC) obtained with the combined use of automatic tube current (mAs) modulation with a quality reference mAs of 25 and sinogram-affirmed iterative reconstruction (SAFIRE), compared to low-dose (LD) CTC acquired with a quality reference mAs of 55 and reconstructed with filtered back projection (FBP). Methods: Eighty-two patients underwent ULD-CTC acquisition in prone position and LD-CTC acquisition in supine position. Both ULD-CTC and LD-CTC protocols were compared in terms of radiation dose [weighted volume computed tomography dose index (CTDI vol) and effective dose], image noise, image quality, and polyp detection. Results: The mean effective dose of ULD-CTC was significantly lower than that of LD-CTC (0.98 and 2.69 mSv respectively, P < 0.0001) with an overall dose reduction of 63.2%. Image noise was comparable between ULD-CTC and LD-CTC (28.6 and 29.8 respectively, P = 0.09). There was no relevant difference when comparing image quality scores and polyp detection for both 2D and 3D images. Conclusion: ULD-CTC allows to significantly reduce the radiation dose without meaningful image quality degradation compared to LD-CTC.
European radiology, 2015
To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the ...
Computed tomographic colonography: clinical value
Abdominal Imaging, 2007
Computed tomographic colonography (CTC) has the potential to reliably detect polyps in the colon. Its clinical value is accepted for several indications. The main target is screening asymptomatic people for colorectal cancer (CRC). As in large multi-centre trials controversial results were obtained, acceptance of this indication on a large scale is still pending. Agreement exists that in experienced hands screening can be performed with CTC. This emphasizes the importance of adequate and intensive training. Besides this, other problems have to be solved. A low complication profile is mandatory. Perforation rate is very low. Ultra-low dose radiation should be used. When screening large patient cohorts, CTC will need a time-efficient and cost-effective management without too many false positives and additional exploration. Can therefore a cut-off size of polyp detection safely be installed? Is the flat lesion an issue? Can extra-colonic findings be treated efficiently? A positive relationship with the gastro-enterologists will improve the act of screening. Improvements of scanning technique and software with dose reduction, improved 3D visualisation methods and CAD are steps in the good direction. Finally, optimisation of laxative-free CTC could be invaluable in the development of CTC as a screening tool for CRC.
AGA future trends report: CT colonography
Gastroenterology, 2004
Since the initial introduction of CTC by Vining et al. in 1994 1 a number of studies have compared CTC with colonoscopy. Early reports typically involved small populations at high risk for colorectal pathology and used single-row scanners. In these studies, the perpolyp analyses showed that CTC was poor at detecting small lesions (sensitivity, 11%-55%) but slightly better for medium-sized (6 -9 mm) and large lesions (Ն10 mm) with sensitivities ranging from 34% to 82% and 50% to 91%, respectively. The per-patient sensitivity, although Abbreviations used in this paper: CT, computed tomography; CTC, computerized tomographic colonography.
Advances in CT Colonography for Colorectal Cancer Screening and Diagnosis
Journal of Cancer, 2013
CT colonography (CTC) is a validated colorectal cancer test that provides an additional minimally-invasive screening option which is likely to be preferred by some patients. Important examination prerequisites include adequate colonic cleansing and distention. Tagging of residual material aids in the differentiation of true polyps from stool. Low radiation dose technique should be employed routinely for screening studies. Readers must be skilled in the use of both 2D and 3D interpretation methods.
Reducing data size and radiation dose for CT colonography
American Journal of Roentgenology, 1997
U sing helical CT data and advanced imaging software, CT colonography provides a complete colorectal examination with minimal patient risk or discomfort. Unlike two-dimensional (2D) axial CT images that are perpendicular to the patient's midline, reformatted 2D CT colonography images are produced at cross sections and orthogonal angles to the colon midline. Threedimensional (3D) CT colonography is a perspective intraluminal imaging technique that simulates an endoscopic view. Preliminary results using CT colonography have been promising for detecting colorectal cancer and polyps 11-41. but clinical usefulness is limited by lengthy image processing times and data storage requirements.