CT has a sensitivity of 100 per cent, while others like digital radiography and digital X-ray have only 85 per cent and 70 per cent respectively
During 1924, Captain T W Barnard, Director, Erstwhile Institute of Radiology at the General Hospital, Madras, helped the police to locate a gold chain in the stomach of a thief by x-raying him.
A few years later, Barnard found precious stones secreted in small cavities inside the cheeks of the women of a band of criminals by x-raying them; police suspected that they stole a large quantity of jewels. Identifying drugs in place of gold will be difficult.
The US Customs and Border Patrol (CBP) seize over a million pounds of drugs (mainly marijuana, cocaine and heroin) annually. Eighty percent of the smugglers caught by CBP practice ‘body packing' of these illegal narcotics.
The May 2008 issue of the Applied Radiology describes the practice of body packing as the trafficking of illicit drugs within the gastrointestinal tract or vagina. According to the journal, body packers are also known as ‘swallowers,' ‘internal carriers,' ‘couriers' or ‘mules.'
A study presented recently at the annual meeting of the Radiological Society of North America (RSNA) identified computed tomography (CT) as the best way to detect cocaine in the body of a ‘mule.'
Dr Patricia Flach, a radiologist at University Hospital of Berne and Institute of Forensic Medicine of Berne in Switzerland and colleagues analyzed images from 89 exams using various imaging methods (CT:27; Digital X-ray: 50 and low-dose linear slit digital radiography (LSDR):12) and performed on 50 suspected drug ‘mules' over a three-year period at University Hospital.
The study group included 45 men and five women aged between 16 and 45. Researchers identified forty-three of the suspects as drug mules. They compared the radiologic findings with a written record of the drug containers recovered from the faeces of suspects.
CT imaging the best
CT imaging allowed the physicians to see all the drug containers, especially when they knew what to look for. Thus the sensitivity of CT is 100 per cent. LSDR had a sensitivity rate of 85 per cent; digital x-ray was able to identify the presence of cocaine containers only 70 per cent of the time.
Intestinal contents are messy and non-uniform in consistency. According to Dr Flach, there were positive findings on CT that were clearly not detectable on conventional x-rays due to overlap of intestinal air, faeces or other dense structures.
The coating and manufacture of the containers changed their appearance, especially on CT images. Rubber-coated condoms filled with cocaine appeared hyper-dense, or white, on CT, while other containers of similar size with plastic foil wrapping appeared iso- to hypo-dense or grey to black.
Dr. Stephen J. Taub, Division of Toxicology, Department of Emergency Medicine, Beth Israel Deaconess Medical Centre, Boston, USA and colleagues stated that body packers usually carry about one kg of drug, divided into 50 to 100 packets of 8 to 10 g each. Smugglers have devised automatic processes to pack drugs densely into latex sheaths or condoms.
Writing in The New England Journal of Medicine, they noted instances in which physicians interpreted two plain abdominal radiographs as negative. The suspects subsequently passed 106 and 135 packets.
Plain abdominal radiographs may be useless to identify drugs in the ‘mules.'
When the law enforcing authorities suspect an individual of being a drug ‘mule,' they often seek the help of radiologists to detect quickly the presence of drugs concealed in the body.
According to the researchers, cocaine containers, which may be swallowed or inserted in the vagina or rectum, can be as large as a banana or as small as a blueberry.
“In these cases it is important for us to know that we have identified all the drug containers in a body, both for legal purposes and for the health of the patient,” Dr. Flach said.
“However, there was no research telling us which imaging modality was best in detecting cocaine containers in the stomach, intestines or other body orifices.”
CT exposes the suspects to higher doses of ionizing radiation. It is obviously of concern while imaging healthy people.
“CT is the way to go," Dr. Flach said. "But low-dose protocols need to be implemented to ensure the safety of the people undergoing the procedure,” she cautioned.
Raja Ramanna Fellow, Department of Atomic Energy email@example.com