Editing Virtual colonoscopy (section)

==Disadvantages==
During virtual colonoscopy, it is not possible to take tissue samples ([[biopsy]]) or remove polyps, so a conventional [[colonoscopy]] must be performed if abnormalities are found.<ref>{{cite web |url=https://www.niddk.nih.gov/health-information/diagnostic-tests/virtual-colonoscopy |title=Virtual Colonoscopy |website= National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), US|access-date= 11 December 2018}}</ref> Also, VC does not show as much detail as a conventional colonoscopy, so polyps smaller than between 2 and 10 millimeters in diameter may not show up on the images.<ref>[http://www.eurekalert.org/pub_releases/2006-10/wfub-cc102406.php Findings presented at the American College of Gastroenterology] annual scientific meeting in Las Vegas, Nev. An abstract of the study was printed in the September 2006 issue of The American Journal of Gastroenterology.</ref> Furthermore virtual colonoscopy performed with CT exposes the patient to [[ionizing radiation]], on the order of a milli[[Gray (unit)|gray]].<ref>{{cite journal|title = Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control?|date = Feb 2011|doi = 10.1007/s00330-010-1922-4|pmid = 20700594|volume=21 |pages=345–52| last1=Lim | first1=Hyun Kyong | last2=Lee | first2=Kyoung Ho | last3=Kim | first3=So Yeon | last4=Kim | first4=Kil Joong | last5=Kim | first5=Bohyoung | last6=Lee | first6=Hyunna | last7=Park | first7=Seong Ho | last8=Yanof | first8=Jeffrey H. | last9=Hwang | first9=Seung-sik | last10=Kim | first10=Young Hoon | journal=European Radiology | issue=2 | s2cid=20987597 }}</ref> Some research has demonstrated that ultra-low dose VC can be just as effective in demonstrating bowel disease due to the great difference in x-ray absorption between air and the tissue comprising the inner wall of the colon.
Optical colonoscopy is taken as the "[[Gold standard (test)|gold standard]]" for colorectal cancer screening by the vast majority of the medical and research communities. However, some radiologists recommend VC as a preferred approach to colorectal screening. Virtual colonoscopy is favored by some professionals because it permits complete visualization of the entire colon, hence providing more opportunity to identify precancerous polyps and cancer, and to then do prompt diagnostic biopsies or therapeutic removal of these lesions.{{cn|date=January 2022}}