After industry representatives cited other medical conferences that allow live demonstrations, RSNA decided this year to reverse a 13-year-old policy and permit ultrasound phantom scanning on the showroom floor.Phantoms are used to mimic human ultrasound
After industry representatives cited other medical conferences that allow live demonstrations, RSNA decided this year to reverse a 13-year-old policy and permit ultrasound phantom scanning on the showroom floor.
Phantoms are used to mimic human ultrasound testing, primarily as a quality control device for institutions. They are also manufactured for other imaging modalities, but the RSNA is not about to allow ionizing radiation on the exhibit floor.
"In ultrasound you need many different phantoms because sound behaves differently with each body and each body part," said Jeff Peiffer, GE Medical Systems manager for ultrasound marketing in the Americas. "It's easier to make a phantom for CT."
Although phantoms will be allowed for ultrasound demonstrations, human subjects will not, and ultrasound vendors ultimately prefer to demonstrate products for potential buyers using real people.
These are not the specters of literaturethey do have shape and substance. Most ultrasound phantoms are tissue-simulating gel inside rectangular boxes. Doppler phantoms have tubes in the tissue with 7- to 9-micron-wide "scatterers" that simulate red blood cells. A few breast phantoms have small simulated lesions in them, so resident physicians can practice needle biopsies.
Several industry veterans recalled that in the past, ultrasound sales personnel have used poultry breasts to simulate human tissue. A few remembered using fish tanks (but the fish refused to hold still).
Phantoms are sometimes designed to resemble actual body parts, although that is time-consuming and expensive. However, Gammex RMI of Middleton, WI, sells "Rachel, the Anthropomorphic Breast Phantom." And brain phantoms are often easy to recognize as brains, because brains look somewhat jellylike to begin with.
Not all ultrasound vendors will bring phantoms to the floor, although salespeople sometimes use them for product demos.
"Acuson will probably not be doing phantom scanning at the RSNA show," said that company's director of marketing Bill Carrano. "A lot of radiology customers felt scanning phantoms was not the same as patients, and we've found they don't really show the true overall value of the system. It's not the real world."
Although an ultrasound system might make a beautiful phantom image, on a patient the results would be of much lower quality because patients move and breathe, Carrano said.
The RSNA last allowed phantom scanning in 1987, according to Steve Drew, assistant executive director of scientific assembly and informatics for the RSNA. He said the ban on phantoms began in 1988 and has been continued until now.
"For health and safety reasons, as well as ethical reasons, RSNA has prohibited live imaging, diagnostic, therapeutic, or health screening procedures on individuals or phantoms," he said. "Exhibitors have not routinely (asked to perform) live ultrasound imaging of phantoms."
The RSNA technical exhibits committee will be monitoring the demonstrations, Drew said, adding that the committee has not set rules for vendors to follow in their phantom scanning.
There are no plans to allow other types of scanning on the exhibit floor, he said, although turkey breasts may be used in hands-on demonstrations in scientific sessions. No mention was made of the meeting's proximity to Thanksgiving.