Radiation risk to the urologist during endourologic procedures, and a new shield that reduces exposure.

OBJECTIVES: With the increasing use of endourologic procedures to diagnose and treat urologic problems, the urologist's exposure to radiation from fluoroscopy becomes an important safety consideration. Although collimation of the x-ray beam generally prevents direct radiation exposure by the urologist, the patient absorbs radiation during the procedure and becomes a secondary source of exposure through radiation scatter. METHODS: We measured radiation exposure to the urologist during endourologic procedures using standard body shields and thyroid collars. We repeated our surveys using a newly designed urologic surgery radiation shield. RESULTS: We found dose rates to the urologist of up to 1100 mrem per hour of flouroscopy time. The maximum yearly whole-body exposure as recommended by the National Council on Radiation Protection is 5000 mrem, or 5 rem. CONCLUSIONS: Urologists should be cognizant of this radiation risk, and the concepts of time, distance, and shielding are critically important to know in efforts to reduce radiation exposure. We introduce a newly designed fluoroscopic drape which reduces the radiation dosage to the urologist from scatter nearly 70-fold. We found this shield to be very practical and easy to use, and we offer it as an effective safeguard against secondary radiation exposure.

A modification of standard percutaneous nephrolithotripsy technique for the morbidly obese patient.

OBJECTIVES: Urolithiasis in the morbidly obese patient presents several unique challenges to the urologist, and its treatment often requires creativity and innovation. We present a new modification of standard percutaneous nephrolithotripsy (PNL) technique, which is very helpful in overcoming some of the problems that are encountered when performing PNL in this group of patients. METHODS: We present 5 patients in whom this new technique has been used. Each had either failed prior extracorporeal shock-wave lithotripsy (ESWL) therapy or their size and abdominal girth precluded use of ESWL technology. All 5 patients underwent PNL. The radiographically measured skin-to-stone distances (determined by computed tomography or ultrasonography or both) exceeded the lengths of the standard percutaneous access sheaths and the 26 F rigid nephroscope. Thus larger and longer Amplatz access sheaths and a 30 F gynecologic laparoscope were used to reach the stones. Standard ultrasonic lithotripsy was then performed, and extralong bronchoscopic grasping forceps were used to remove stone fragments. RESULTS: All 5 patients were rendered stone-free using this technique. There was no significant perioperative morbidity. CONCLUSIONS: For this very challenging group of patients, the use of larger and longer access sheaths and the gynecologic laparoscope have been very effective additions to the urologists' armamentarium in the treatment of urolithiasis.

The diagnosis of acute pyelonephritis in the piglet using single photon emission computerized tomography dimercaptosuccinic acid scintigraphy: a pathological correlation.

Single photon emission computerized tomography (SPECT) scintigraphy has proved to be an extremely sensitive renal imaging modality in children with genitourinary pathology, including pyelonephritis, particularly when compared to 2-dimensional planar imaging. This study was undertaken to corroborate SPECT dimercaptosuccinic acid (DMSA) scintigraphic findings with specific histopathology in acute pyelonephritis. Unilateral vesicoureteral reflux was produced in 19 Yorkshire piglets 3 to 4 weeks old. The bladders of 12 animals were inoculated with Escherichia coli 2 weeks later, after baseline SPECT DMSA scans had been obtained. The animals were then re-imaged at 3 (4), 7 (4) or 14 (4) days after infection and sacrificed for histological evaluation. Seven purposefully uninfected piglets with unilateral reflux served as controls and were followed for up to 6 weeks before imaging and sacrifice. SPECT proved to be 97% sensitive and 93% specific in providing the diagnosis of acute pyelonephritis. The SPECT findings were manifest by a spectrum of abnormal findings (mottling, striations, inner cortical scalloping and focal cortical defects), which correlated precisely with the extent and severity of cortical involvement in the acute pyelonephritic process. We propose a new classification scheme for SPECT DMSA renal scintigraphic imaging, and believe that this modality is exquisitely sensitive in providing the diagnosis as well as in evaluating the extent of renal parenchymal involvement when acute pyelonephritis is induced in the animal model.