Biomedical subjects

D Bhaduri

Publications and source records attributed to D Bhaduri.

3 recordsLinked to original sources

PubMed1979

Compton scatter densitometry in cancellous bone.

A single-source low-energy Compton densitometer has been used to investigate the effects of multiple scattering on density determinations. The relative electron density and mass density were determined in samples of known density, and in samples of human cancellous bone tissue. The influence of sample diameter on the measured relative electron density of known samples was investigated. The measured value was strongly dependent on the diameter and the density range of the sample. The bias inherent in the density determination which is attributable to multiple scattering and attenuation in human femoral bone was evaluated, and a correction for these effects is suggested for clinical measurements.

Bone and Bones↗

PubMedDate not supplied

Geometrical considerations for Compton scatter densitometry.

The determination of the physical density by Compton scatter densitometry is dependent upon the geometry used for the measurement. The diameter of the sample, the density range, and the scattering volume size and shape influence the relative electron density values obtained by such a system. This work presents the results of an experimental analysis of these parameters in which the importance of each is evaluated for samples of known density. A bias in the computed Compton density, due to multiple scattering and attenuation, is defined; and an expression relating the density bias to these geometrical parameters is presented. The importance of applying corrections to the computed physical density for samples of large diameter and/or high density (cortical bone tissue and large diameter cancellous bone tissue) is discussed.

Bone and Bones↗

PubMedDate not supplied

Dose distribution from a Delta-25 head scanner.

The dose distribution pattern from a Delta-25 head scanner was evaluated experimentally in a 17.5-cm-diam cylinder water phantom for different scan speed and slice thickness combinations. TLD chips were used to measure the dose at different points across the scan section. The isodose curves thus obtained were found to be asymmetric, with the regions of maximum and minimum dose near the surface on the opposite sides of the phantom. The effect of changing the scan thickness and speed on dose was evaluated and a linear increase in dose with the increase of slice thickness was observed. This was consistent with the design of the line focus and the beam collimators used in this system. The effect of multiple slice scan on the dose was also evaluated.

Humans↗