The Effect of Lemonade and Diet Lemonade Upon Urinary Parameters Affecting Calcium Urinary Stone Formation.

PURPOSE: To determine the effects of regular and diet lemonade upon urinary parameters affecting kidney stone formation. METHODS: In this prospective blinded crossover study, 12 healthy participants consumed either 2 L of regular or diet lemonade daily while on a standardized low sodium moderate calcium diet. Twenty four-hour urine collections were obtained at baseline on the controlled diet only and on days 4 and 5 of each treatment phase. There was a 1-week washout period between regular and diet lemonade treatments. Primary outcomes were urine citrate, pH, and volume determined by 24-hour urine collections. Secondary outcomes included the supersaturation of calcium oxalate, calcium phosphate, and uric acid. RESULTS: Urine volume was significantly higher with both regular and diet lemonade consumption compared with baseline values. Urinary citrate significantly increased from baseline with diet lemonade only. Urine pH was unchanged with both beverages. The supersaturation of calcium oxalate significantly decreased with diet lemonade only, whereas supersaturation of calcium phosphate decreased with both beverages. Daily consumption of 2 L of regular and diet lemonade resulted in an intake of 168.4 and 170.2 mEq of citrate but a total alkali intake of 12.2 and 16.0 mEq, respectively. Compared with diet lemonade, regular lemonade provided subjects with 805 additional calories and 225 g of sugar per day. CONCLUSIONS: Diet lemonade may provide a low-calorie sugar-free cost-effective option for decreasing the risk of recurrent calcium nephrolithiasis through a significant increase in urine volume, increase in urinary citrate, and reduction in supersaturation of calcium oxalate and calcium phosphate.

In automated fluoroscopy settings, does shielding affect radiation exposure to surrounding unshielded tissues?

BACKGROUND AND PURPOSE: Automatic brightness control (ABC), a function of modern fluoroscopy machines, adjusts radiation intensity in real time to enhance image quality. While shielding reduces radiation exposure to protected areas, it is unknown how much radiation adjacent unshielded areas receive when using ABC settings. Our purpose was to assess radiation dosage to shielded and unshielded tissue when using fluoroscopic ABC mode compared with fixed exposure settings. MATERIALS AND METHODS: In a simulated ureteroscopy, thermoluminescent dosimeters (TLDs) were placed at three sites in a female human cadaver, including the right renal hilum, right distal ureter adjacent to the uterus, and directly over the uterus. The cadaver received 60 seconds of radiation exposure using a C-arm fluoroscopy system under ABC and fixed settings (1.38 mAs, 66 kVp) with and without uterine shielding. Radiation dosage absorbed by the TLDs was compared using two-way analysis of variance and least-squares confidence intervals. RESULTS: Shielding significantly reduced radiation dose to the uterus by 62% and 82% (P<0.05 for both) in ABC and fixed settings, respectively. Shielding of the uterus in ABC, however, resulted in an approximately twofold increase in radiation dosage to the ureter and ipsilateral kidney (P<0.05 for both) and a decrease in image quality. Using fixed settings, shielding of the uterus did not increase radiation dose to the ipsilateral ureter and kidney. CONCLUSION: There is a significant increase in radiation dosage to surrounding tissues when shielding is used with ABC mode during fluoroscopy. Radiation can be reduced and image quality improved by using fixed settings when shielding is indicated.