THE TECHNICAL PROBLEMS IN COMPUTED TOMOGRAPHY

Mathematical Problems in Computed Tomography

Estimating the Radiation-Induced Cancer Risks in Pediatric Computed Tomography

Introduction One of the central questions in radiological protection is the magnitude of the risks from low doses of radiation, related to the justification and optimization of the diagnostic medical exposures. Therefore, the aim of this study was to estimate the cancer incidence and mortality risks in children of different ages, sizes, and ethnicities undergoing computed tomography examination...

Computed Tomography (CT) Perfusion in Abdominal Cancer: Technical Aspects

Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed table position. Advances in reconstruction algorithms make it possible to reduce the radiation dose fo...

Dose Reduction Methods in Chest Computed Tomography

Introduction: Computed tomography is one of the most powerful tools for investigating thorax disease, because it shows progression of lung disease much clearer than chest radiography. Technical advances in CT scanners have led to some abilities for CT scanners such as coverage of larger volume, lower noise and ability for acquiring image in one respiratory phase. However, this will be accompani...

The conjugate gradient regularization method in Computed Tomography problems

In this work we solve inverse problems coming from the area of Computed Tomography by means of regularization methods based on conjugate gradient iterations. We develop a stopping criterion which is eecient for the computation of a regularized solution for the least{squares normal equations. The stopping rule can be suitably applied also to the Tikhonov regularization method. We report computat...