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Biomedical subjects

P Randaccio

Publications and source records attributed to P Randaccio.

7 recordsLinked to original sources
PubMed2005

A Simulator for X-ray images.

A simulator for X-ray images is presented based on a virtual X-ray source and a virtual human body obtained from tomographic slices. In the simulator it is possible to modify the tube potential, the anodic current, the exposure time, the filtration and some geometric parameters such as source-skin distance, orientation and field size. The virtual body consists of a three-dimensional voxel matrix in which CT numbers for each point of the body are stored. The interactions of X rays passing through the body are evaluated using the pencil beam technique. The image is obtained by computing the dose absorbed by the detector and converting it into optical density using a proper response function. The image spatial resolution is limited by the voxel size. The influence of each parameter on the image quality can be observed interactively. The dose absorbed in each point of the body is an important parameter obtained as output of the simulator.

Computer Simulation↗
PubMed1988

[Automation of radiotherapy plans with the use of a personal computer].

A system for the automation of radiotherapy treatment planning is described, implemented by a personal computer, which can be employed with both electromagnetic and corpuscular radiation beams, once the characteristics of the beams employed have been recorded. The use of both moving-field and fixed-field techniques is considered. Along the beams, wedge filters and limitation blocks can be interposed. When calculating the radiation dose, both beam obliquity and inhomogeneous tissue structure are to be considered. Dose distribution can be optimized and adapted to the patient's needs.

Humans↗
PubMed1984

Gamma-irradiation effects on phosphatidylcholine multilayer liposomes: calorimetric, NMR, and spectrofluorimetric studies.

Chemical and structural modifications in multilayer liposomes of synthetic phosphatidylcholine induced by gamma irradiation are investigated with different techniques. Fluorescence anisotropy of the DPH probe and differential scanning calorimetry reveal a broadening of the main lipid transition and the disappearance of pretransition. Fluorescence anisotropy is shown to be higher in the irradiated sample and particularly so at low temperatures. NMR and TLC results show that lysolecithin and palmitic acid are formed with a consequent change in bilayer organization. The possibility that these modifications may account for the permeability variations observed in irradiated natural membranes is discussed.

Calorimetry, Differential Scanning↗
PubMed1979

[A program for optimizing radiation beam parameters in radiotherapy (author's transl)].

A very large-use optimization technique for radiation treatment planning is presented. Very few input data are sufficient to enable the program to work out an optimized dose distribution; optimization is obtained by modifying the intersection point of beams and the size, the wedge and the time of each beam. The technique may be extended to moving beam teletherapy. A memorized collection of typical geometric arrangements allows a good saving in operator's time especially during data preparation.

Computers↗