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• The algorithm developed was applied prospectively in patients to check its validity. • The present study was divided into ex vivo and in vivo experiments. • Non-invasive characterization of calcium renal stones is quite useful in selecting suitable treatment modality. • This study introduces the concept of DECT based characterization of materials using effective atomic number (Z eff) and electron density(ρ e) Non-invasive DECT based characterization of renal stones using their effective atomic number (Z eff) and the electron density (ρe) in patients. This paper aims to develop a method for in-vivo characterization of renal stone. Differentiation of renal stones in-vivo especially sub types of calcium stones have very important advantage for better judgement of treatment modality. 50 extracted renal stones were scanned ex-vivo using dual energy CT scanner. A method was developed to characterize these renal stones using effective atomic number and electron density obtained from dual energy CT data. The method and formulation developed in ex-vivo experiments was applied in in-vivo study of 50 randomly selected patients of renal stones who underwent dual energy CT scan. The developed method was able to characterize Calcium Oxalate Monohydrate (COM) and the combination of COM and Calcium Oxalate Dihydrate (COD) stones non-invasively in patients with a sensitivity of 81% and 83%respectively. The method was also capable of differentiating Uric, Cystine and mixed stones with the sensitivity of 100, 100 and 85.71% respectively. The developed dual energy CT based method was capable of differentiating sub types of calcium stones which is not differentiable on single energy or dual energy CT images. [ABSTRACT FROM AUTHOR]

Aim: This study aims to develop a method using dual-energy computed tomography (DECT) to determine the effective atomic number and electron density of substances. Materials and Methods: Ten chemical substances of pure analytical grade were obtained from various manufacturers. These chemicals were pelletized using a hydraulic press. These pellets were scanned using DECT. A relation was obtained for the pellet's atomic number and electron density with their CT number or Hounsfield unit (HU) values. Calibration coefficients were determined. Five new chemical pellets were scanned, and their effective atomic number and electron densities were determined using the calibration coefficients to test the efficacy of the calibration method. Results: The results obtained for effective atomic number and electron density from the HU number of DECT images were within ±5% and ±3%, respectively, of their actual values. Conclusions: DECT can be used as an effective tool for determining the effective atomic number and electron density of high atomic number substance. [ABSTRACT FROM AUTHOR]