Biomaterial Database

Effects of fractionated irradiation on mouse lung and a phenomenon of slow repair. 1976

S B Field, and S Hornsey, and Y Kutsutani

The LD/50 between 40 and 180 days after irradiation of the thorax has been taken as a measure of lung damage in mice. The method has been used to derive the relationship between total dose, number of fractions (N) and overall treatment time (T). For X rays the results fit an Ellis type of relationship, i.e. total dose alphaN0-25 T0-07. This only applies for more than 8 fractions, below which N0-39 becomes a good fit to the results. For neutrons, the best fit is total dose alphaT0-07. Various possible explanations for the T factor are discussed, but for lung damage we attribute it to a slow repair process which possibly may only be observed in slowly proliferating tissues. Slow repair is about 100 times less rapid than Elkind-type of repair of sublethal damage and whereas Elkind repair is greatly reduced for irradiation with fast neutrons, relative to X rays, slow repair is not.

UI	MeSH Term	Description	Entries
D007928	Lethal Dose 50	The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.	LD50,Dose 50, Lethal
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
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
D011833	Radiation Injuries, Experimental	Experimentally produced harmful effects of ionizing or non-ionizing RADIATION in CHORDATA animals.	Experimental Radiation Injuries,Injuries, Experimental Radiation,Experimental Radiation Injury,Radiation Injury, Experimental
D002470	Cell Survival	The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.	Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D005214	Fast Neutrons	Neutrons, the energy of which exceeds some arbitrary level, usually around one million electron volts.	Fast Neutron,Neutron, Fast,Neutrons, Fast
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor