title: Non-invasive vesicoureteral reflux detection: heating risk studies for a new device.
abstract: OBJECTIVE
  To investigate a novel non-invasive device developed to warm bladder urine and to measure kidney temperature to detect vesicoureteral reflux.
  
  
  METHODS
  Microwave antennas focused energy within the bladder. Phantom experiments measured the results. The heating protocol was optimized in an in-vivo porcine model, and then tested once, twice and three times consecutively in three pigs followed by pathologic examinations.
  
  
  RESULTS
  Computer simulations showed a dual concentric conductor square slot antenna to be the best. Phantom studies revealed that this antenna easily heated a bladder phantom without over heating intervening layers. In-vivo a bladder heating protocol of 3 min with 30 W each to two adjacent antennas 45 s on 15 s off followed by 15 min of 15 s on and 45 s off was sufficient. When pigs were heated once, twice and three times with this heating protocol, pathologic examination of all tissues in the heated area showed no thermal changes. More intensive heating in the animal may have resulted in damage to muscle fibers in the anterior abdominal wall.
  
  
  CONCLUSIONS
  Selective warming of bladder urine was successfully demonstrated in phantom and animals. Localized heating for this novel vesicoureteral reflux device requires low-power levels and should be safe for humans.
authors.affiliation: University of Utah and Primary Children's Medical Center, Salt Lake City, UT 84113, USA. brent.snow@hsc.utah.edu
authors.forename: B W
authors.initials: BW
authors.lastname: Snow
authors.forename: K
authors.initials: K
authors.lastname: Arunachalam
authors.forename: V
authors.initials: V
authors.lastname: De Luca
authors.forename: P F
authors.initials: PF
authors.lastname: Maccarini
authors.forename: O
authors.initials: O
authors.lastname: Klemetsen
authors.forename: Y
authors.initials: Y
authors.lastname: Birkelund
authors.forename: T J
authors.initials: TJ
authors.lastname: Pysher
authors.forename: P R
authors.initials: PR
authors.lastname: Stauffer
mesh_terms: D000818:Animals; D003950:Diagnostic Techniques, Urological; D006358:Hot Temperature / Q000009:adverse effects; D066298:In Vitro Techniques; D007668:Kidney; D008872:Microwaves; D034421:Sus scrofa; D013696:Temperature; D001743:Urinary Bladder; D014556:Urine; D014718:Vesico-Ureteral Reflux / Q000175:diagnosis*