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Additional Applications THE E X PLORER TOTA L'BODY PE T scanner's improved signal collec- tion capability opens the door to potential uses ranging far beyond oncology. According to the device's lead developers at the University of California, Davis, a few of those applications include: + Assessing the responses of patients with diabetes to pre- scribed exercise regimens + Identifying reservoirs of diseases such as AIDS + Examining maternal-fetal interac- tions to better understand how certain disorders develop in utero + Studying the brain/gut connection that could play a role in the devel- opment of obesity and diabetes + Following the paths and activities of cells used in regenerative medicine to refi ne self-heal- ing therapies Additionally, total-body PET may make it possible to follow the path of antibody and antibody- derived agents intended to treat cancer and infl ammatory diseases through the body, as well as observe processes that take place concurrently in disparate parts of the body, according to Antonio Sastre, PhD, Program Director of the Division of Applied Science and Technology at the National Institute of Biomedical Imaging and Bioengineering. "The ability to track complex metabolic or physiologic pathways which may be taking place nearly simultaneously in different places in the body, such as activation of brown fat by a number of external or internal stressors, may open new perspectives in research," Sastre says. because the scanner only sees part of the body at a ny one time, but the radiation is a l l t h roug hout t he body, em it ti ng away," he says. To solve t hat problem, t he patient n e e d s t o b e s u r r ou n d e d b y d e t e c - t ors t hat ca n col lect a s much of t he radioactive tracer's sig na l as possible, according to Cher r y. He a nd his col- leag ue, Ra msey Badawi, PhD, Chief of Nuclea r Medicine at UC Davis Medica l Center a nd Professor of Radiolog y a nd Biomedica l Eng ineering at UC Davis, have developed a PET sca nner that is intended to do just that. A SURGE IN SIGNAL COLLECTION A f ter more tha n a decade of concep- tua lization, desig n a nd development, Cher r y a nd Ba daw i have developed EXPLORER , a tota l-body PET scanner with a 6-foot gantry and 560,000 signa l detectors — 10 times more than those feat ured i n conventiona l mach i nes, according to Cherr y. Sha nghai-based United Imaging Hea lthcare produced a sma ll-sca le version of EXPLORER in early 2017 that is being used in anima l tria ls at UC Davis School of Veterinary Medicine. Cherr y a nd Badawi expect to begin human research tria ls in 2018. Conventiona l PET sca nners require a patient to move through the sca nner du r i n g a n exa m t o i ma ge t he ent i re body. With EXPLOR ER , the patient will enter the bore a nd rema in stationa r y while the machine obta ins a full-body i m a ge . C her r y a nd B a d aw i pr e d ic t EX PLOR ER will improve radiotracer sig na l collection by a factor of 40 for a whole-body sca n. " You could choose to use that entire factor of 40 to speed up the sca n; you c ou ld do a s c a n of t he w hole b o d y in 1/40th of the time that we currently do t he sca n ," Cher r y say s . "A fa i rly t y pica l 20-minute protocol could now be done in 30 seconds. You cou ld use that factor-of- 40 sig na l collection in other ways, as well, or at least pa r t of it. You could use it to reduce the injected dose ... or to col lect more sig na l a nd get better-qua lit y sca ns. You have this massive improvement in sig na l collec- tion, and you can use it in different ways depending on the task at ha nd." A GAME CHANGER IN CARING FOR PATIENTS? The impact of EX PLOR ER on the way clinicia ns detect a nd assess ca ncer, as well as eva luate the success of oncologic t herapies, cou ld be tremendous. The machine may be able to identify sma ller, less active lesions a nd a llow clinicia ns to be more def initive in their judgments of treatments' ef f icacy, according to Badawi. He says EX PLOR ER may a lso eliminate a common problem of PET. "Breathing motion is the single most impor ta nt degrading factor in terms of spatia l accuracy when sca nning t he t hora x ," Ba daw i says. " If you [cou ld sca n a patient] in 30 seconds, you c ou ld do a breath-hold PET." A fa ster sca n wou ld be especia l ly impor ta nt for the pediatric population. " You ca n reduce the need for a nes- thesia or even do away with it in some cases if you sca n fast enough," Badawi says. "[Children] a re more susceptible t o ra d i at ion dose [t h a n a du lt s], but anesthesia itself a lso carries significant risks — more so tha n radiation. If you could obviate the need for anesthesia in even a fraction of the pediatric popula- tion, that would be a big dea l." Jacobs, with NCI, cautions that the dev ice faces yea rs of st udy before it enters clinica l ca re. "I'd expect the clinica l eff icacy tria ls to beg in in about four to f ive yea rs ... in pa ra llel with eng ineering effor ts to bring it to practica l a nd cost-effective ma nufact ur ing, fol lowed by g radua l expa nsion of ava ilabilit y over the fol- lowing years," she says. "If the increase in throughput a nd qua lity a re rea lized, both patient ca re a nd hea lthca re costs will benef it." ■ M D N E W S .C O M /// M D N E W S C L E V E L A N D /A K R O N / C A N T O N 2 017 2 1