Pricop C et al, 2015: Extracorporeal shock waves lithotripsy versus retrograde ureteroscopy: is radiation exposure a criterion when we choose which modern treatment to apply for ureteric stones?
Pricop C, Maier A, Negru D, Malau O, Orsolya M, Radavoi D, Serban DR
University of Medicine and Pharmacy of Iasi
The aim of this study is to compare two major urological procedures in terms of patient exposure to radiation. We evaluated 175 patients, that were subjected to retrograde ureteroscopy (URS) and extracorporeal shock waves lithotripsy (ESWL) for lumbar or pelvic ureteral lithiasis, at two urological departments. The C-arm Siemens (produced in 2010 by Siemens AG, Germany) was used for ureteroscopy. The radiological devices of the lithotripters used in this study in the two clinical centers had similar characteristics. We evaluated patient exposure to ionizing radiation by using a relevant parameter, the air kerma-area product (PKA; all values in cGy cm2), calculated from the radiation dose values recorded by the fluoroscopy device. PKA depends on technical parameters that change due to anatomical characteristics of each case examined, such as body mass index (BMI), waist circumference, and stone location. For the patients subjected to ESWL for lumbar ureteral lithiasis the mean of PKA (cGy cm2) was 509 (SD=180), while for those treated for pelvic ureteral lithiasis the mean of PKA was 342 (SD=201). In the URS group for lumbar ureteral lithiasis, the mean of PKA (cGy cm2) was 892 (SD=436), while for patients with pelvic ureteral lithiasis, the mean of PKA was 601 (SD=429). The patients treated by URS had higher exposure to ionizing
radiation dose than patients treated by ESWL. The risk factors of higher radiation doses were obesity, exposure time, and localization of the stones.
Bosn J Basic Med Sci. 2014 Oct 18;14(4):254-8. FREE ARTICLE
This report is of particular interest inasmuch as it has its focus on radiation during urological procedures. It is stated that the radiation doses are calculated for a projection area of 100 cm2. This means that the corresponding apertures either are a circular field with diameter of 11 cm or a square of 10 x 10 cm. It needs to be emphasized that reduction of the aperture (projection area) is an extremely important step during SWL, URS and all other stone removing procedures. It is my own experience that this step, unfortunately, too often is neglected! Quotients between radiation dose and fluoroscopy time are useful indicators of the extent of aperture reduction.
To me the result presented in this study was slightly surprising because my guess would have been that the radiation dose was higher for SWL, but this was obviously not the case. There are, however, certainly pronounced differences in radiation exposure between different centres, urologists and treatment strategies.
The important message of this report is that there is continuous need of attention to the radiation dose and always with the aim of keeping this dose as low as possible. In this regard a compromise is necessary because insufficient use of fluoroscopy during treatment might result in poor treatment result and need of repeated treatments with more radiation. Attention to radiation exposure is also particularly important in view of the common and generous use of CT-examinations for diagnosis and follow-up.