Biomaterial Database

[Changes of the dose at the surface in oblique incidence of high energy photon beams]. 1994

S Dupont, and S Rosenwald, and H Beauvais

Service de physique médicale, Institut Curie, Paris.

For oblique incident photon beams, the absorbed dose is markedly different from normal incident beams. Our aim was to study the changes of the dose at the surface and in the build-up region for oblique incident 4, 6, 10, 15, 25 MV photon beams angled 0 degree to 80 degrees for square fields ranging from 5 x 5 to 30 x 30 cm2. All doses were measured as a function of the depth along the beam axis and used to define an obliquity factor. For all energies investigated, we have studied the obliquity factor as a function of depth, field sizes, energy and angle of incidence. Our results show that the obliquity factor is highly dependent on these different parameters. In addition, by considering the equivalent squares of the entrance fields distorted by obliquity, an analytical method has been developed to predict the dose at the surface of high energy photon beams for various angles and field sizes.

UI	MeSH Term	Description	Entries
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008962	Models, Theoretical	Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Experimental Model,Experimental Models,Mathematical Model,Model, Experimental,Models (Theoretical),Models, Experimental,Models, Theoretic,Theoretical Study,Mathematical Models,Model (Theoretical),Model, Mathematical,Model, Theoretical,Models, Mathematical,Studies, Theoretical,Study, Theoretical,Theoretical Model,Theoretical Models,Theoretical Studies
D011879	Radiotherapy Dosage	The total amount of radiation absorbed by tissues as a result of radiotherapy.	Dosage, Radiotherapy,Dosages, Radiotherapy,Radiotherapy Dosages
D011882	Radiotherapy, High-Energy	Radiotherapy using high-energy (megavolt or higher) ionizing radiation. Types of radiation include gamma rays, produced by a radioisotope within a teletherapy unit; x-rays, electrons, protons, alpha particles (helium ions) and heavy charged ions, produced by particle acceleration; and neutrons and pi-mesons (pions), produced as secondary particles following bombardment of a target with a primary particle.	Megavolt Radiotherapy,High-Energy Radiotherapy,Radiotherapy, Megavolt,High Energy Radiotherapy,Radiotherapy, High Energy
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man