Material and Methods: The biomaterial bolus consists of Cycowood and brass. Since the probability of nuclear fragmentation is different between low-Z and high-Z materials with the same water equivalent length, the shape of Bragg curves depends on the material through which carbon ions pass. Then we have developed an accurate dose calculation model taking into account the effect by using an inte...

1. Seated subjects stopped ventilation briefly at end expiration while a 5 ml bolus of 133Xe was injected close to the mouth. They then inspired air at different flow rates and the distribution of radioactivity in the lungs was measured with a scanning technique during a period of breath-holding at maximal inspiration. 2. In five normal subjects the dependent zones received a greater fraction o...

Spherical monodisperse ferromagnetic iron oxide particles of 1.9-microm geometric and 4.2-microm aerodynamic diameter were inhaled by 13 healthy nonsmoking subjects using the shallow bolus technique. The bolus width was 100 ml, and the penetration front depth was 150 +/- 27 ml. The mean flow rate during inhalation and exhalation was 250 ml/s. The Fowler dead space and the phase 1 dead space of ...

An x-ray imaging system is described that can be used for obtaining arterial blood flow information. The system consists of a linear photodiode array image detector, simple optical and mechanical components, and a data acquisition microcomputer that connect to a conventional x-ray image intensifier based fluorography system. Flow information is obtained by detecting the movement of a small, loc...

Introduction Bolus is a soft and resilient material which is used for increasing skin dose or to even out the irregular patient contour. The main property of various materials used presently as bolus is the water-equivalent electron density. Ethyl methacrylate is used as a soft-liner in dentistry and its physical and chemical properties are proved to be nontoxic for human body. The goal of this...

Computed tomography thoracic angiography studies were performed on five adult beagles using the bolus tracking (BT) technique and the test bolus (TB) technique, which were performed at least two weeks apart. For the BT technique, 2 mL/kg of 300 mgI/mL iodinated contrast agent was injected intravenously. Scans were initiated when the contrast in the aorta reached 150 Hounsfield units (HU). For t...

A new approach to the modeling of the marker in Perfusion CT and Perfusion MR datasets is outlined and initial results given. The technique is based on estimation of the dilation and delay of an estimated bolus shape and a template fit to an new solution of the heat equation. Initial results are provided.