CT Scan Of Soft-Bodied Leech Opens Door To New Research

Researchers have successfully performed a CT scan of Chtonobdella tanae, a terrestrial leech with a soft body that is typically difficult to scan. When it comes to such invertebrates — those with a soft body, that is — researchers usually must dissect the creature to learn about its inner part, or section it and create a 3D model using those sections. A CT scan, though, produces a model much quicker and without killing the specimen.

The successful scan was recently detailed by the American Museum of Natural History, which reports soft-bodied invertebrates are traditionally difficult to scan due to soft tissues permitting x-rays to pass through uninhibited. It would be necessary to increase the contrast of the scans, which could be done using a contrasting dye.

The researchers experimented with different "fixatives," eventually finding one dubbed "AFA" which works when refixed using osmium tetroxide to bind osmium in the soft tissues. AFA is composed of acetic acid, formalin, and alcohol. The tests were first done on a North American leech, and after proving successful, later done on a new species of leech found in Australia.

This new leech is only a couple centimeters long and about two millimeters wide, making it too tiny for researchers to dissect. The leech has been named after author Amy Tan, and thanks to the new contrasting solution, has been CT scanned at a high resolution, revealing the creature's inner structure to researchers.

SOURCE: American Museum of Natural History