The purpose of bowtie filters in CT scanners is to homogenize the x-ray intensity measured by the detectors in order to improve the image quality and at the same time to reduce the dose to the patient because of the preferential filtering near the periphery of the fan beam. For CT dosimetry, especially for Monte Carlo calculations of organ and tissue absorbed doses to patients, it is important ...

SUMMARY: Technologic advances in CT have generated a dramatic increase in the number of CT studies, with a resultant increase in the radiation dose related to CT scanning. Such increase in radiation dose is becoming a concern for the radiology community, especially with increasing public awareness of the dose burden related to examinations. To cope with the increase in CT-related radiation expo...

Current estimation of radiation dose from computed tomography (CT) scans on patients has relied on the measurement of Computed Tomography Dose Index (CTDI) in standard cylindrical phantoms, and calculations based on mathematical representations of "standard man". Radiation dose to both adult and pediatric patients from a CT scan has been a concern, as noted in recent reports. The purpose of thi...

abstract   background: while the benefits of computed tomography (ct) are well known in accurate diagnosis, those benefits are not risk free. ct is a device with higher patient dose in comparison with other conventional radiological procedures. is the reduction of exposures by requiring optimization of ct procedures [a principle concern in radiological protection]? in this study, the radiation ...

  ABSTRACT   Background: While the benefits of Computed Tomography (CT) are well known in accurate diagnosis, those benefits are not risk free. CT is a device with higher patient dose in comparison with other conventional radiological procedures. Is the reduction of exposures by requiring optimization of CT procedures [a principle concern in radiological protection]? In this study, the radiatio...

The objective of this study was to compare the diagnostic accuracy of positron emission tomography/low-dose computed tomography (PET/ldCT) versus the same technique implemented by contrast-enhanced computed tomography (ceCT) in staging Hodgkin’s disease (HD). Forty patients (18 men and 22 women, mean age 30 9.6) with biopsy-proven HD underwent a PET/ldCT study for initial staging including an u...

BACKGROUNDAND PURPOSE: There is a desire within many institutions to reduce the radiation dose in CTP examinations. The purpose of this study was to simulate dose reduction through the addition of noise in brain CT perfusion examinations and to determine the subsequent effects on quality and quantitative interpretation. MATERIALS ANDMETHODS: A total of 22 consecutive reference CTP scans were id...

Purpose: To compare image resolution using Iterative Reconstruction (IR) with the resolution using Filtered Back Projection (FBP), for low-contrast objects in phantom images across vendors and exposure levels. Materials and Methods: Randomized repeat scans of the Gammex 464 American College of Radiology (ACR) CT Accreditation Phantom (Module 2, Low-contrast) were performed for multiple radiatio...

PURPOSE As cone-beam CT (CBCT) systems dedicated to various imaging specialties proliferate, technical assessment grounded in imaging physics is important to ensuring that image quality and radiation dose are quantified, understood, and justified. This paper involves technical assessment of a new CBCT scanner (CS 9300, Carestream Health, Rochester, NY) dedicated to imaging of the ear and sinuse...