Biomaterial Database

Computed LET distributions in the build-up region of tissue for 14 MeV neutrons. 1979

D P Bhatia, and P S Nagarajan

Experimental radiobiological investigations of fast neutron beams involve irradiation of thin cell layers. The irradiation of cells is done either in free air or with a material such as graphite, TE plastic or bone-equivalent plastic covering the cells. This paper discusses the computed dose distributions in LET at shallow depths between 5 or 10 micrometers and the equilibrium depth, and the influence of the overlying materials on the distributions. The secondaries considered are elastic recoils of H, C, N and O, and 22 alpha particle groups and the corresponding heavy recoils arising from (n, alpha) events in C, N, O, P and Ca. Dose-average LET and curves of detailed dose distributions in LET as a function of depth in tissue are given for various overlying materials.

UI	MeSH Term	Description	Entries
D009502	Neutrons	Electrically neutral elementary particles found in all atomic nuclei except light hydrogen; the mass is equal to that of the proton and electron combined and they are unstable when isolated from the nucleus, undergoing beta decay. Slow, thermal, epithermal, and fast neutrons refer to the energy levels with which the neutrons are ejected from heavier nuclei during their decay.	Neutron
D011829	Radiation Dosage	The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).	Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D005214	Fast Neutrons	Neutrons, the energy of which exceeds some arbitrary level, usually around one million electron volts.	Fast Neutron,Neutron, Fast,Neutrons, Fast