A Study on Radiation Dose Received by Patients during Extracorporeal Shock Wave Lithotripsy

BACKGROUND

Extracorporeal shock wave lithotripsy (ESWL) is considered as the method of choice for treatment of most stone diseases. The present study aims to evaluate radiation dose received by patients undergoing ESWL.

METHODS

In total, 46 patients from both genders were referred to the Shohadaye Ashayer hospital of Khorramabad, Iran and were included in the present study. Patients were positioned in anteroposterior (AP) projection and along 30° anterior oblique (AO) projection upon the X-ray fluoroscopy table and exposures were conducted. Thermoluminescent dosimeters (TLDs) were used for radiation dose measurements. To evaluate the entrance surface dose (ESD), each TLD chip was taped on back of patient at the entrance surfaces of the X-ray beam.

RESULTS

The mean number of stones in each patient was 1.4. The stone sizes ranged from 7 to 29 mm, and a mean of 3200 pulses were need for each patient. The mean ESD in the postero-anterior (PA) and oblique X-ray beam entrance were obtained at 12.04 and 68.84 mGy, respectively. There was linear correlation between patient dose with fluoroscopy time, tube current (mA), tube potential (kVp) and patient position (P < 0.001); however, we found no strong correlation between patient dose with patient body mass (P = 0.837), number of shock wave pulses (P = 0.089), stone size (P = 0.773) and locations (P = 0.463).

CONCLUSION

The data obtained in the current study are comparable with information available in the literature. They emphasized that ESWL exposes patients to much more radiation compared to those from conventional radiography and is in the range of computed tomography (CT) procedures. Therefore, following safety guidelines is recommended.

FOP: still turning into stone

Fibrodysplasia ossificans progressiva (FOP) is a rare catastrophic genetic condition of extraskeletal (heterotopic) ossification. One in every two million people is affected worldwide, with no ethnic, racial, gender, or geographic predisposition. Most cases of FOP arise from a spontaneous missense mutation in the gene encoding bone morphogenic protein (BMP) type II receptor (ACVR1/ALK2). Affected individuals are normal at birth apart from malformed great toes. Onset of clinical symptoms is usually in the first decade of life, presenting with episodic emergence of painful rapidly appearing tumor-like soft tissue swellings (flare-ups). Heterotopic bone replaces the skeletal muscles, tendons, ligaments, and connective tissue at the site of the damage through a process of endochondral ossification, causing fixation of joints and permanent limitation of motion. Most affected individuals are confined to wheelchair in the third decade of life. Worldwide rate of misdiagnosis of FOP is very high; clinicians often fail to associate the two classic clinical features of FOP: rapidly developing soft tissue swellings and the abnormal great toes. The current case presents a previously undiagnosed 39-year-old FOP patient, sadly a victim of lack of clinical awareness of this rare condition. As a result of repetitive iatrogenic harm, he has tragically "turned into stone."