• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5111-5116
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• 2014

Computed Tomography Colonography (CTC) is a medical imaging technology used in identifying polyps and colon cancer masses in the large intestine. The technique has evolved a great deal since its invention and has become a routine diagnostic procedure in Western countries due to its non invasiveness and ease of use. The objective of our study was to explore the possibility of CTC application in Indian hospitals. This paper gives an overview of the procedure and its commercial viability. The explanation begins with the domain aspects from gastroenterologist perspective, the new way of thinking in polyp classification, the technical components of CTC procedure, and how engineering solutions have helped clinicians in solving the complexities involved in colon diagnosis. The colon cancer statistics in India and the results of single institution study we carried out with retrospective data is explained. By considering the increasing number of patients developing colon malignancies, the practicality of CTC in Indian hospitals is discussed. This paper does not reveal any technical aspects (algorithms) of engineering solutions implemented in CTC.

• Clinical Endoscopy
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• v.55 no.2
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• pp.183-190
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• 2022

Colorectal cancer is an important cause of morbidity and mortality worldwide. Optical colonoscopy (OC) is widely accepted as the reference standard for the screening of colorectal polyps and cancers, and computed tomography colonography (CTC) is a valid alternative to OC. The purpose of this review was to assess the diagnostic accuracy of OC and CTC for colorectal lesions. A literature search was performed in PubMed, Embase, and Cochrane Library, and 18 articles were included. CTC has emerged in recent years as a potential screening examination with high accuracy for the detection of colorectal lesions. However, the clinical application of CTC as a screening technique is limited because it is highly dependent on the size of the lesions and has poor performance in detecting individual lesions <5 mm or flat lesions, which, although rarely, can have a malignant potential.

• Clinical Endoscopy
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• v.55 no.1
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• pp.101-112
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• 2022

Background/Aims: The aim of our study was to determine the efficacy of computed tomography colonography (CTC) in screening for colorectal cancer (CRC). Methods: A total of 612 females and 588 males aged 45 to 75 years were enrolled in CTC screening. CTC was performed following standard bowel preparation and colonic insufflation with carbon dioxide. The main outcomes were the detection rate of CRC and advanced adenoma (AA), prevalence of colorectal lesions in relation to socio-demographic and health factors, and overall diagnostic performance of CTC. Results: Overall, 56.5% of the 1,200 invited subjects underwent CTC screening. The sensitivity for CRC and AA was 0.89 and 0.97, respectively, while the specificity was 0.71 and 0.99, respectively. The prevalence of CRC and AA was 3.0% (18/593) and 7.1% (42/593), respectively, with the highest CRC prevalence in the 66-75 age group (≥12 times; odds ratio [OR], 12.11; 95% confidence interval [CI], 4.45-32.92). CRC and AA prevalence were inversely correlated with Asian descent, physical activity, and negative fecal immunochemical test results (OR=0.43; 95% CI, 0.22-0.83; OR=0.16; 95% CI, 0.04-0.68; OR=0.5; 95% CI, 0.07-3.85, respectively). Conclusions: Our study revealed high accuracy of CTC in diagnosing colonic neoplasms, good compliance with CTC screening, and high detection rate of CRC.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.214-227
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• 2013

Computed tomographic scan as a screening procedures in asymptomatic individuals has seen a steady increase with the introduction of multiple-raw detector CT scanners. This report provides a brief review of the current controversy surrounding CT cancer screening, with a focus on the radiation induced cancer risks and clinical efficacy. 1. A large study of patients at high risk of lung cancer(the National Lung Screening Trial[NLST]) showed that CT screening reduced cancer deaths by 20%(1.33% in those screened compared with 1.67% in those not screened). The rate of positive screening tests was 24.2% and 96.4% of the positive screening results in the low-dose CT group were false-positive. Radiation induced lung cancer risk was estimated the most important in screening population because ERR of radiation induced lung cancer does not show the decrease with increasing age and synergistic connection between smoking and radiation risk. Therefore, the radiation risk may be on the same order of magnitude as the benefit observed in the NLST. Optimal screening strategy remain uncertain, CT lung cancer screening is not yet ready for implementation. 2. Computed tomographic colonography is as good as colonoscopy for detecting colon cancer and is almost as good as colonoscopy for detecting advanced adenomas, but significantly less sensitive and specific for smaller lesions and disadvantageous for subsequent therapeutic optical colonoscopy if polyps are detected. The average effective dose from CT colonography was estimated 8-10 $mS{\nu}$, which could be a significant dose if administered routinely within the population over many years. CT colonography should a) achieve at least 90% sensitivity and specificity in the size category from 6 and 10 mm, b) offer non-cathartic bowl preparation and c) be optimized and standardized CT parameters if it is to be used for mass screening. 3. There is little evidence that demonstrates, for whole-body scanning, the benefit outweighs the detriment. This test found large portion of patient(86~90.8%) had at least one abnormal finding, whereas only 2% were estimated to have clinically significant disease. Annual scans from ages 45 to 75 years would accrue an estimated lifetime cancer mortality risk of 1.9%. There is no group within the medical community that recommends whole-body CT. No good studies indicate the accuracy of screening CT, at this time. The benefit/risk balance for any of the commonly suggested CT screening techniques has yet to be established. These areas need further research. Therefore wild screening should be avoided.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8351-8358
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• 2016

Electronic cleansing is an image post processing technique in which the tagged colonic content is subtracted from colon using CTC images. There are post processing artefacts, like: 1) soft tissue degradation; 2) incomplete cleansing; 3) misclassification of polyp due to pseudo enhanced voxels; and 4) pseudo soft tissue structures. The objective of the study was to subtract the tagged colonic content without losing the soft tissue structures. This paper proposes a novel adaptive method to solve the first three problems using a multi-step algorithm. It uses a new edge model-based method which involves colon segmentation, priori information of Hounsfield units (HU) of different colonic contents at specific tube voltages, subtracting the tagging materials, restoring the soft tissue structures based on selective HU, removing boundary between air-contrast, and applying a filter to clean minute particles due to improperly tagged endoluminal fluids which appear as noise. The main finding of the study was submerged soft tissue structures were absolutely preserved and the pseudo enhanced intensities were corrected without any artifact. The method was implemented with multithreading for parallel processing in a high performance computer. The technique was applied on a fecal tagged dataset (30 patients) where the tagging agent was not completely removed from colon. The results were then qualitatively validated by radiologists for any image processing artifacts.