Effective radiation exposure evaluation during a one year follow-up of urolithiasis patients after extracorporeal shock wave lithotripsy.

348 Central European Journal of Urology UROLITHIASIS ORIGINAL PAPER Effective radiation exposure evaluation during a one year follow-up of urolithiasis patients after extracorporeal shock wave lithotripsy Mehmet Kaynar1, Erdem Tekinarslan2, Suat Keskin3, İbrahim Buldu4, Mehmet Giray Sönmez5, Tuna Karatag6, Mustafa Okan Istanbulluoglu6 Department of Urology, Selcuk University, Faculty of Medicine, Konya, Turkey Department of Urology, Konya Education and Research Hospital, Konya, Turkey 3 Department of Radiology, Necmettin Erbakan University, Faculty of Medicine, Konya, Turkey 4 Department of Urology, Mevlana University, Faculty of Medicine, Konya, Turkey 5 Medical Park Ankara Hospital, Ankara, Turkey 6 Department of Urology, Faculty of Medicine, Mevlana University, Konya, Turkey 1 2 Citation: Kaynar M, Tekinarslan E, Keskin S, et al. Effective radiation exposure evaluation during a one year follow-up of urolithiasis patients after SWL. Cent European J Urol. 2015; 68: 348-352. Article history Submitted: Jan. 22, 2015 Accepted: June 2, 2015 Published on-line: Sept. 26, 2015 Corresponding author Mehmet Kaynar Selcuk University Faculty of Medicine Department of Urology Selçuk Üniversitesi Alaeddin Keykubat Kampüsü 42075 Konya, Turkey phone +905333916339 Introduction To determine and evaluate the effective radiation exposure during a one year follow-up of urolithiasis patients following the SWL (extracorporeal shock wave lithotripsy) treatment. Material and methods Total Effective Radiation Exposure (ERE) doses for each of the 129 patients: 44 kidney stone patients, 41 ureter stone patients, and 44 multiple stone location patients were calculated by adding up the radiation doses of each ionizing radiation session including images (IVU, KUB, CT) throughout a one year follow-up period following the SWL. Results Total mean ERE values for the kidney stone group was calculated as 15, 91 mSv (5.10-27.60), for the ureter group as 13.32 mSv (5.10-24.70), and in the multiple stone location group as 27.02 mSv (9.41-54.85). There was no statistically significant differences between the kidney and ureter groups in terms of the ERE dose values (p = 0.221) (p >0.05). In the comparison of the kidney and ureter stone groups with the multiple stone location group; however, there was a statistically significant difference (p = 0.000) (p <0.05). Conclusions ERE doses should be a factor to be considered right at the initiation of any diagnostic and/or therapeutic procedure. Especially in the case of multiple stone locations , due to the high exposure to ionized radiation, different imaging modalities with low dose and/or totally without a dose should be employed in the diagnosis, treatment, and follow-up bearing the aim to optimize diagnosis while minimizing the radiation dose as much as possible. Key Words: urolithiasis ‹› SWL ‹› radiation exposure ‹› follow-up INTRODUCTION There are various invasive and non-invasive treatment modalities in kidney and ureter stone treatments, each with inherent advantages, disadvantages, and differing stone free rates. Patients undergoing shock wave lithotripsy (SWL) due to urolithiasis make up a major part of the uroradiological practice because Cent European J Urol 2015; 68: 348-352 of the various diagnostic procedures used. Imaging plays a significant role in the diagnosis, treatment, and follow-up of urolithiasis. Although ultrasonography, plain abdominal radiography (KUB), and intravenous urography (IVU) are widely used in urolithiasis diagnosis, non-contrast computer tomography (NCCT) is accepted as the golden standard in the urinary system stone diagnosis due to the higher sensitivity and specificity when compared to IVU [1]. doi: 10.5173/ceju.2015.547 349 Central European Journal of Urology Urolithiasis with a high recurrence rate of 50%, affects 5–15% of the total world population. Simple renal calculi of <2 cm can be successfully treated up to 80–85% of the time with SWL in patients with normal renal anatomy [2]. There are numerous factors with an impact on both the urologists’ and patients’ diagnosis and treatment- related decision making mechanisms. Radiation exposure due to high recurrence rate and intense and close follow up is among one of the important disadvantages of SWL in urolithiasis. It is estimated that radiation exposure during NCCT to diagnose urolithiasis may lead to fatal malignancy in 1/1000 [3]. Throughout a single year, 50 millisieverts (mSv) or 20 mSv per year for a 5-year period are accepted as the threshold levels for “safe” exposure by the International Commission on Radiological Protection (ICRP) [4]. A recent study about the effective radiation exposure in evaluation and follow-up of patients with urolithiasis confirmed that 17.3% had surpassed that 50 mSv/a year threshold level determined by the ICRP within the first year [5]. Effective radiation exposure (ERE) evaluation during the one year follow-up of urolithiasis patients following the SWL treatment was calculated and compared according to stone locations in the present study. MATERIAL AND METHODS With a minimum follow-up of 12 months, 129 patients who had undergone SWL (ELMED Complit lithotripsy system, Turkey) due to renal stones ≤20 mm, ureteral stones ≥10 mm, and/or in conditions requiring active removal of the stones in size of <10 mm from September 2010 to January 2012 were reviewed retrospectively. Patient age, gender, and number of ionizing radiation sessions, including images obtained via KUB, IVU and CT were registered. Exclusion criteria: patients younger than 18 and older than 80 years of age, surgical intervention following SWL, presence of conditions decreasing SWL efficacy such as severe obesity, skeletal malformations, renal insufficiency, and composition of the stone (hardness such as cystine), participation less than a year. The amount of effective radiation exposure for each scan was calculated using the dose length product (DLP) of the CT scanner (Siemens Somatom Emotion 16 CT Scanner, Germany) during a standard CT scan protocol. The effective radiation exposure dose (reported in mSv) of each CT scan was calculated by multiplying the DLP (reported in mSv/cm) by the 0,015 conversion factor [6, 7]. ERE doses for the 2-view KUB was calculated as 1.7 mSv and for an IVU as 2.5 mSv [5, 8]. Total ERE doses for each patient was calculated by adding up the radiation doses of each ionizing radiation session, including images (IVU, KUB, CT) throughout a one year follow-up period following the SWL. Data analysis was conducted using an SPSS version 20 package program. Statistical analysis of the variance was made with a One-Way ANOVA test. P <0.05 was taken as the cut-off point to determine the statistical significance. RESULTS A total of 129 patients, 42 female and 87 male, were evaluated in the present study. In the kidney stone group there were 44 patients, 14 female and 30 male with a mean age of 43.4 (23-76). In the ureter stone group ther (...truncated)