Radiation Dose and Screening for Vesicoureteral Reflux

Abstract

AJR 2010; 194:W1 0361–803X/10/1942–W1 © American Roentgen Ray Society Radiation Dose and Screening for Vesicoureteral Reflux We read with interest the review by Dr. Lim [1] concerning recent advances in the diagnosis of vesicoureteral reflux (VUR). The article provides an otherwise excellent review of the current controversy regarding VUR screening methods; however, we are concerned by the lack of attention given to the radiation dose from 99mTc-dimercaptosuccinic acid (DMSA) renal scans. At our institution, a DMSA renal scan performed in a 1-year-old child carries a 1.3-fold higher radiation dose than continuous fluoroscopy voiding cystourethrography (VCUG), a 10-fold higher radiation dose than pulsed fluoroscopy VCUG, and a 200-fold higher radiation dose than radionuclide cystography [2]. Importantly, because of the lack of clinical guidelines or standardized dosimetry, there is marked variation in the administered radiation dose for children undergoing nuclear medicine scans [3]. As a result, these figures may, in fact, underestimate the excess radiation dose associated with a systemic abandonment of the bottom-up (i.e., early cystography) approach in favor of the top-down (i.e., early DMSA scan) approach. It has been postulated that adoption of the top-down approach would result in a decrease in the number of patients diagnosed with VUR who are not actually at risk of renal damage, clearly a worthy and admirable goal. However, relatively little evidence is yet available to support this claim, and both the American Academy of Pediatrics and the American Urological Association continue to recommend the bottom-up approach in screening children at risk of VUR [4, 5]. Thus, a commitment to the as low as reasonably achievable (ALARA) principle for our young patients would seem to suggest that providers should shift to the topdown approach only after a preponderance of evidence shows that the clinical benefits merit the inevitable accompanying increase in radiation dose. Jonathan C. Routh Richard S. Lee Jeanne S. Chow Children’s Hospital Boston Harvard Medical School Boston, MA