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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients, referring physicians, the media, and government agencies have all expressed concern over the risks of medical radiation, particularly as it relates to CT. This concern is particularly paramount when associated with a screening examination such as CT colonography. These theoretical risks must be weighed realistically against the substantial benefits of colon cancer screening as well as against the risks inherent in the major alternative screening option, optical colonoscopy. When put into perspective, the risk-benefit ratio is highly in favor of the performance of CT colonography. Nevertheless, in following the ALARA principle, there is an ever increasing armamentarium of options that can be employed in the pursuit of CT radiation dose reduction, all of which can be used in many synergistic combinations allowing for dose reduction while simultaneously preserving image quality and minimizing image noise. After a brief tutorial on estimating radiation dose, various strategies will be discussed including reductions in tube current and tube voltage as well as the use of automatic dose modulation and iterative reconstruction. Other practical considerations will also be reviewed including proper patient isocentering, optimization of colonic insufflation to minimize additional decubitus scans, proper choice of scan volumes to avoid overranging, and variation of slice thickness and window width to minimize perceived image noise. Finally, a strategy for how to incrementally introduce these methods as well as a way to compare dose reduction efforts across institutions throughout the country will be offered.
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PMID:Dose reduction methods for CT colonography. 2322 77

A rare case of a tracheal bronchus coexisting with a left-shifted carina and an acute angle of left main bronchus is presented. A 66 year old man with a history of colon cancer was scheduled for right thoracoscopic pericardial window due to recurrent pericardial effusion. After induction of anesthesia, the trachea was intubated using a 39-French, left-sided double lumen tube (DLT); the DLT was positioned with fiberoptic bronchoscopic guidance. Significantly high airway pressure was noticed as we initiated one-lung ventilation after the patient was positioned in the left lateral decubitus position. While repositioning the DLT, we found an aberrant tracheal bronchus. Although multiple attempts were made to adjust the DLT so as to achieve lung isolation, we could not place the DLT in the appropriate position due to abnormal and distorted anatomy. Lung isolation was unsuccessful; both lungs were carefully ventilated with small tidal volumes.
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PMID:Difficulty in placement of a left-sided double-lumen tube due to aberrant tracheobronchial anatomy. 2396 14