Evaluation of optimal parameters for using low-dose computed tomography to diagnose urolithiasis

• Published in: Radiation physics and chemistry (Oxford, England : 1993) England : 1993), 2017-11, Vol.140, p.242-246
• Main Authors: Chen, Hui-Hsien, Yu, Cheng-Ching, Hsu, Fang-Yuh
• Format: Article
• Language: English
• Subjects: Calculus; Computation; Computed tomography; Computer simulation; Diagnostic systems; Dose conversion factor; Dosimeters; Effective dose; Image quality; Kidney stones; Low-dose computed tomography; Medical diagnosis; Patients; Physicians; Polymethyl methacrylate; Radiation dosage; Radiography; Tomography; Urinary tract radiography; Urography; Urolithiasis; Urology
• ISSN: 0969-806X; 1879-0895
• DOI: 10.1016/j.radphyschem.2017.02.036

Urolithiasis is a common disease; patients suspected of suffering from urolithiasis will be examined by abdomen x-ray, Sono, Intraudio Videonous Urography (IVU) and Computed Tomography (CT). The detection rates for calculus in above examinations are respectively: 50–70% (x-ray), 50–60% (Sono), 70–90% (IVU) and 97% (CT). In addition, the effective doses are respectively: 0.63mSv (x-ray), no radiation dose (Sono), 2.6mSv (IVU) and 8–16mSv (CT). Although CT has the highest detection rate for calculus, it also has the highest radiation dose. This research sought to lower the radiation dose by using CT scans with different dose conditions of standard dose (SD), 50% SD, 25% SD, and 15% SD to diagnose patients who suffer from urolithiasis and thus explore the feasibility of examining urolithiasis via CT with lower dose conditions. This research simulated the examination of patients with RANDO phantom, collocating PMMA slice phantom and pig's kidney. Fake calculuses made of five different materials of different sizes were put into the phantom and scanned individually. The results of the scanned images were given to two physicians who had many years of diagnostic experience to interpret the urolithiasis images. This study explored the different image qualities of CT with different dose conditions. In addition, this research used thermoluminescent dosimeters (TLD) to measure the radiation doses and compared the results with the dose values shown on the screen of the CT scanner to estimate the dose conversion factor (k). The research results showed that a low-dose CT was able to provide good image quality and thus have a lower radiation dose. Therefore, a low-dose CT is suggested the main examination method to diagnose patients with urolithiasis. •This study lower CT scan doses with different conditions to diagnose urolithiasis.•RANDO, PMMA phantoms and pig kidney were used to simulate a patient in examination.•Fake calculuses made of different materials were put into the phantom to scan.•CT dose conversion factor (k) of 0.029 (mSvmGy−1cm−1) for ICRP 103 was obtained.•LDCT is suggested the main examination method to diagnose urolithiasis patients.