Absorbed dose	Absorbed dose is the mean energy imparted to a quantity of matter divided by the mass of that matter i.e. energy per unit massUnit: J kg-1Special name: gray (Gy) 1Gy = 1J kg-1Typical radiation processing dose of 25 kGy delivered to water results in a temperature rise of ≈6 deg.C.
Accelerator	A machine capable of accelerating charged particles in a vacuum and discharging the resultant particulate or other radiation into another medium.
Activity	The number of nuclear transitions occurring in a given quantity of radioactive material per unit of time. For example one disintegration/second is a becquerel (Bq), which has replaced curie (Ci) as the standard unit of activity.
Alanine Dosimeter	Irradiation of the amino acid alanine produces stable free radicals:H H| Ionising |H3C-C-COOH --------> H3C-C-COOH| Radiation • NH2The concentration of the radicals is proportional to the absorbed dose and can be measured by Electron Paramagnetic Resonance (EPR) spectroscopy.
Atom	The smallest particle of an element that cannot be divided or broken up by chemical means. It consists of a central core of protons and neutrons called the nucleus. Electrons revolve in orbits in the region surrounding the nucleus.
Backscattering	Primary radiation deflected or secondary radiation emitted in the general direction of the incident radiation beam
batch	Defined quantity of bulk, intermediate, or finished product that is intended or purported to be uniform in character and quality, and which has been produced during a defined cycle of manufacturing.
beam window	The beam window is where the electron beam leaves the accelerator and comes into air, where the product is being exposed. The window is a tightly fastened foil of titanium of around 50 microns, fixed in a flange by multiple screws and a metal seal. It has to be cooled by compressed air as a small percentage of the electrons are trapped within the windows and induce heat. There is a high stress on the material, as the atmospheric pressure is bending der windows inwards. It has to be cleaned, checked and replaced regularly in order to avoid an implosion of the accelerator with excessive damage.
Becquerel (Bq)	The unit of radioactive decay equal to 1 disintegration per second. 37 billion (3.7 x 1010) becquerels = 1 curie (Ci).
Betas	A beta is a high speed particle, identical to an electron, that is emitted from the nucleus of an atom
Bioburden	The total number of all viable aerobic bacteria, yeasts and moulds expressed as colony forming units (CFU) per unit or gram of product.
Biological shield	A mass of absorbing material placed around a reactor or radioactive source to reduce the radiation to a level safe for humans.
Bremsstrahlung	X-rays emitted when a charged particle (such as an electron) is decelerated by passing through matter. The word bremsstrahlung is German for "braking radiation".
Calibration	The adjustment, as necessary, of a measuring device such that it responds within the required range and accuracy to known values of input.
Cathode	In physics a cathode is an electrode in a vacuum tube or other vacuum system which produces electrons. Electrons are extracted from metal electrodes either by heating the electrode, causing thermionic emission, or by applying a strong electric field and causing field emission. Electrons can also be emitted from the electrodes of certain metals when light of frequency greater than the threshold frequency falls on it. This is called photoelectric emission. Cathodes used for field emission are called cold cathodes. Heated electrodes, frequently called filaments, are much more common. They form the source of the electron beam in cathode ray tubes and the electrodes for fluorescent lamps. The electron beam in an accelerator is produced by a filament.
Cavity	central compartment in the Rhodotron accelerator, in which the electrons are accelerated. The cavity of the Rhodotron TT 300 accelerator has a diameter of 2 meters. The Rhodotron is based on the principle of "re-circulationg" a beam through successive diameters of a single coaxial cavity resonating in metric waves. 10 Successive crossings of the electrons are required to achieve 10 MeV at the exit of the Rhodotron. The cavity is under high vaccum during use, and it consists of welded steel with a plating of copper.
Change Control	A formal system by which qualified representatives of appropriate disciplines review proposed or actual changes that might affect a validated status. The intent is to determine the need for action that would ensure and document that the system is maintained in a validated state
Chemical recombination	Following an ionization event, the positively and negatively charged ion pairs may or may not realign themselves to form the same chemical substance they formed before ionization. Thus, chemical recombination could change the chemical composition of the material treated by ionizing radiation.
cobalt	A chemical element with atomic number 27. Cobalt was discovered by Brandt in 1735. The name cobalt is derived from Kobold, an evil German spirit, and results from the interference of Cobalt in Copper mining. Until 1540, it was believed that the cobalt mineral was unusable. Adding the mineral to glass produces a bright blue color (from which we get the phrase cobalt blue).
cobalt 60	a radioactive isotope of cobalt having a mass number of 60 and a half-life of 5.27 years. Cobalt 60 is a nuclear product that generates gamma rays and is the leading source for industrial gamma irradiation . It produces two gamma rays with energies of 1.17 MeV and 1.33 MeV
Commissioning	An engineering term that covers all aspects of bringing a system or sub-system to a position where it is regarded as being ready for use in pharmaceutical manufacture. Commissioning involves all the basis requirements of Installation Qualification (IQ) and Operational Qualification (OQ).
Concurrent Validation	Validation carried out during routine production of products intended for sale
Continuous Process	A process that occurs in an assembly line fashion where the assembly line keeps moving with new products entering the process and old products exiting the process at all times. (In gamma facilities using Pallet irradiators this form of processing is used with the conveyors carrying the totes acting as the “assembly line”.)
Crosslinking	crosslinking is when individual polymer chains are linked together by covalent bonds to form one giant molecule.
Curie (Ci)	The basic unit used to describe the intensity of radioactivity in a sample of material. The curie is equal to 37 billion (3.7 x 1010) disintegrations per second, which is approximately the activity of 1 gram of radium. A curie is also a quantity of any radionuclide that decays at a rate of 37 billion disintegrations per second. It is named for Marie and Pierre Curie, who discovered radium in 1898.
Date Processed	Date (day/month/year) on which a load of product has been irradiated or removed from the chamber
Decay	The decrease in the amount of any radioactive material with the passage of time due to spontaneous emission from the atomic nuclei of either alpha or beta particles, often accompanied by gamma radiation. Every radionuclide has a definite half-life.
Decay, radioactive	The decrease in the amount of any radioactive material with the passage of time due to the spontaneous emission from the atomic nuclei of either alpha or beta particles, often accompanied by gamma radiation.
D-Max	The maximum radiation dose that can be delivered to a product before unacceptable damage occurs.
D-Min	The minimal radiation dose required to sterilize the product to the desired sterilization assurance level (SAL).
Dose	The absorbed dose, given in rads (or in SI units, grays), that represents the energy absorbed from the radiation in a gram of any material. Furthermore, the biological dose or dose equivalent, given in rem or sieverts, is a measure of the biological damage to living tissue from radiation exposure.
Dose Audit	A set of procedures performed to ensure the dose is still correct. The population and sterilization resistance of microorganisms vary with environmental conditions such as temperature and moisture. Thus, verification of the appropriateness of the sterilizing dose is performed quarterly as a dose audit.
Dose mapping	An exercise conducted within the irradiation equipment to determine the distribution of absorbed dose throughout a load of product or simulated product of specified density ("dummy product") arranged in the irradiation container in a defined configuration A dose mapping study is to be performed in order to identify the minimum and maximum dose zones within the product load, using a predetermined loading pattern. This verifies that the minimum sterilization dose is achieved, while material integrity is maintained by staying within the maximum allowable dosage. In addition, the dose mapping study establishes the reproducibility of the sterilization process and is used in the selection of the dose monitoring locations for routine processing.
Dose rate	The ionizing radiation dose delivered per unit time. For example, Gy or kGy per hour.
Dose, absorbed	Dose, absorbed The amount of energy deposited in any substance by ionizing radiation per unit mass of the substance. It is expressed numerically in rads or grays.
dosimeter	A device that measures radiation dose. Synonym: dose meter.
Dosimetry	The theory and application of the principles and techniques involved in the measurement and recording of ionizing radiation doses.
Dummy product	A material that closely approximates the physical and, where practical, thechemical characteristics (e.g. viscosity, particle size, pH etc.) of the product under validation. In many cases, these characteristics may be satisfied by a placebo product batch
Electromagnetic (em) wave	Electromagnetic waves make up the electromagnetic spectrum.Visible light, ultraviolet, infrared, radio and TV signals are all examples of "everyday" em waves. X-rays, microwaves and high energy photons or gamma rays are also electromagnetic waves.
Electron	An elementary particle with a negative charge and a mass 1/1837 that of the proton. Electrons surround the positively charged nucleus and determine the chemical properties of the atom.
Electron Beam	a focused stream of electrons.
Electron Accelerator
Endotoxin	A fever producing substance for human beings. Every lot of blood or spinal fluid contacting devices must be tested for Endotoxic bacteria (generally using an LAL test) prior to release.
eV (electronvolt)	The basic unit of energy used in high energy physics. It is the energy gained by one electron when it moves through a potential difference of one volt. By definition an eV is equivalent to 1.6 x 10-19 joules. This is a very small amount of energy and the more commonly used multiples are MeV (million eV), GeV (billion eV or giga-electronvolt) and TeV (trillion eV).
Free Radical	An unstable and highly reactive molecule, bearing an atom with an unpaired electron, that nonspecifically reacts with a variety of organic structures such as DNA. The interaction of ionizing radiation with water can generate free radicals in the form of hydroxyl and hydroperoxyl groups that are potent oxidizing agents.
FWT-60 SERIES RADIACHROMIC DOSIMETERS	FWT-60 series of radiochromic dosimeters are designed for radiation processing. They are thin, colorless films that gradually change to deep blue in relation to absorbed dose. Colorless derivatives of the family of aminotriphenyl- methane dyes can be made radiochromic: that is they will change from colorless to a deeply colored state as a function of absorbed dose. The FWT-60 series of dosimeters use hexa(hydroxyethyl) aminotriphenylacetonitrile (HHEVC) dye. Analysis of the dosimeters is simple using a photometer or spectrophotometer. FWT manufactures Radiachromic readers designed specifically for analyzing its dosimeters. The wavelengths in general use are 510 nm and 600 or 605 nm. Together they cover the whole range of the dosimeter. http://www.fwt.com/racm/fwt60ds.htm
Gamma Radiation	High-energy, short wavelength electromagnetic radiation emitted from the nucleus of an atom. Gamma rays are very penetrating and are shielded by dense materials such as lead. Gamma rays are similar to X rays.
Gamma Rays	Gamma rays are electromagnetic waves or photons emitted from the nucleus (center) of an atom.
Grafting	Reaction in which one or more species of block are connected to the main chain of a macromolecule as side chains having constitutional or configurational features that differ from those in the main chain.
Gray (Gy)	The gray is a unit used to measure a quantity called absorbed dose. This relates to the amount of energy actually absorbed in some material, and is used for any type of radiation and any material. One gray is equal to one joule of energy deposited in one kg of a material. The unit gray can be used for any type of radiation, but it does not't describe the biological effects of the different radiations.
ICT	Insulated core transformer. A principle for electron beam accelerators. The high voltage is produced by a 3-phase transformer with multiple secondary windings that are energized by insulated core segments in an iron core. The resulting voltage and current are transferred to an accelerator tube and tungsten wire filament. The electrons omitted by the tungsten filament are then accelerated by means of voltage differential. Once the accelerated electrons pass through the accelerator tube, they are deflected magnetically (scanned) so as to sweep a larger irradiation field.
Induced Radioactivity	Radioactivity produced in any material as a result of nuclear reactions, especially by absorption of neutrons.
Installation Qualification (IQ)	The performance and documentation of tests to ensure that equipment (such as machines, measuring equipment) used in a manufacturing process, areappropriately selected, correctly installed and work in accordance withestablished specifications
Ionization	The process of adding to or removing one or more electrons from atoms or molecules, thereby creating ions and free radicals. High temperatures, metabolic processes, electrical discharges, and radiation can cause ionization.
Ionizing Radiation	Radiation that has enough energy to eject electrons from electrically neutral atoms, leaving behind charge atoms or ions. There are four basic types of ionizing radiation: Alpha particles (helium nuclei), beta particles (electrons), neutrons, and gamma rays (high frequency electromagnetic waves, x-rays, are generally identical to gamma rays except for their place of origin.) Neutrons are not themselves ionizing but their collisions with nuclei lead to the ejection of other charged particles that do cause ionization.
Isotope	Any two or more forms of an element having identical or very closely related chemical properties and the same atomic number but different atomic weights or mass numbers.
Joule	Measure of energy. Deposition of one Joule/Kg is equal to 1 Gy or 100 rads.
Linear Accelerator	A type of particle accelerator in which charged particles are accelerated in a straight line, either by a steady electrical field or by means of radiofrequency electric fields. In the latter variety, the passage of the particle is synchronized with the phase of the accelerating field
Maximum Dose Determination	Definition -- Maximum dose determination is the establishment of a maximum level of radiation to which the product is to be exposed and which will not effect the form, fit, or function of the product. Typically, the maximum dose is at least two times the minimum sterilization dose. This provides an adequate processing window for electron beam sterilization. The maximum dose is established by the irradiation of representative samples of the product at various dose levels to determine the dose level at which form, fit, or function is compromised.
Megacurie (MCi)	One million curies
MeV (Mega Electron Volt)	Energy equal to that acquired by a particle with one electronic charge in passing through a potential difference of one million volts.
Minimum Dose Determination	Minimum dose determination is the establishment of the minimum level of radiation which will effectively and consistently eradicate inherent bioburden levels within a specific product or product family.
Operational Qualification (OQ)	Documented verification that the system or sub-system performs as intended throughout all anticipated operating ranges
Pallet Irradiator	An irradiator that processes entire pallets instead of carriers and/or totes.
Parameters	A set of physical properties approved by the customer whose values determine the characteristics of the processing cycle
Performance Qualification or PQ	another expression for the process validation
Photon	The indivisible unit or quantum of electromagnetic radiation. The photons' energy determines the radiation's nature from radio waves at the lowest energy levels through infrared, visible, and ultraviolet light to X or gamma rays, which have energy high enough to ionize atoms.
Photon radiation	Forms of electromagnetic radiation such as x-rays, gamma rays and sunlight.
product family	Products grouped together for sterilization purposes by similarity of raw materials, components, design, and manufacturing processes
Prouct group	Grouping of Products -- The grouping of products can be used to minimize the amount of testing required to establish the minimum dose for each product and/or group of products. Factors to be considered for grouping of products for minimum dose establishment are typically based upon the manufacturing process itself, which includes handling of the product by employees, machine-made parts versus hand-assembled parts, materials of construction, and raw materials suppliers if a purchased sub-assembly is included in the manufacturing process.
Rad	A unit of radiation dose equal to 100 ergs deposited in 1 gram of tissue or other material. The rad is not an SI unit and is mainly used by some U.S. scientists. Some scientific journals will not accept the rad unit when you submit a paper for publication. They prefer that you use the gray, which corresponds to 100 rad.
Radiation	Radiation is energy in transit in the form of high speed particles and electromagnetic waves. We encounter electromagnetic waves every day. They make up our visible light, radio and television waves, ultra violet (UV), and microwaves with a large spectrum of energies. These examples of electromagnetic waves do not cause ionizations of atoms because they do not carry enough energy to separate molecules or remove electrons from atoms.
Radiation shielding	Reduction of radiation by interposing a shield of absorbing material between any radioactive source and a person, work area, or radiation-sensitive device.
Radiation source	Usually a sealed source of radiation used in teletherapy and industrial radiography, as a power source for batteries (as in use in space craft), or in various types of industrial gauges. Machines, such as accelerators and radioisotope generators, and natural radionuclides may be considered sources.
Re-Validation	A repeat of the process validation to provide an assurance that changes in the process/equipment introduced in accordance with change control procedures do not adversely affect process characteristics and product quality
sample item portion (SIP):	Defined portion of a health care product unit which is tested.
Scan horn	A triangular shaped steel structure, in which the accelerated electrons are sweeped in X and Y direction, in oder to give a homogenous field of radiation. At the bottom of the Scan horn, the beam window is placed and the electrons leave the system to irradiate the product.
SI units	The international system of units as defined by the general conference on weights and measures in 1960. These units are generally based on meter/kilogram/second units, with special quantities for radiation including the becquerel, gray, sievert.
sterility	The absence of viable microorganisms
sterility assurance level (SAL):	The probability of having a non-sterile product unit. For example, an SAL of 10-6 demonstrates a one in one million probability of a non-sterile product unit. The AAMI/ISO standards generally require demonstrating a SAL of 10-6.
sterilization dose:	Minimum absorbed dose required to achieve the specified sterility assurance level.
Units of radiation dose	a) Definitions. As used in this part, the units of radiation dose are: Gray (Gy) is the SI unit of absorbed dose. One gray is equal to an absorbed dose of 1 Joule/kilogram (100 rads). Rad is the special unit of absorbed dose. One rad is equal to an absorbed dose of 100 ergs/gram or 0.01 joule/kilogram (0.01 gray). Rem is the special unit of any of the quantities expressed as dose equivalent. The dose equivalent in rems is equal to the absorbed dose in rads multiplied by the quality factor (1 rem=0.01 sievert). Sievert is the SI unit of any of the quantities expressed as dose equivalent. The dose equivalent in sieverts is equal to the absorbed dose in grays multiplied by the quality factor (1 Sv=100 rems).
Validation Master Plan	A document providing information on the company’s validation work programme. It should define details of and timescales for the validation work to be performed. Responsibilities relating to the plan should be stated
Validation Protocol	A written plan stating how validation will be conducted, including testparameters, product characteristics, production equipment and decision points on what constitutes acceptable test results
Validation Report	Document reporting the validation activities, the validation data and the conclusions drawn.
VALIDATION:	A documented procedure that allows to deliver, record and interpret the results necessary to show, that a process is constantly in accordance with the predefined specifications. Comment: In case of sterilization with wet heat, validation consists of a complete program that covers commissioning and performance qualification. The current understanding of experts of validation of sterilization processes includes two basis requirements (reproducibility and documentation) that are not inherent in the word itself. Reproducibility: Validation shall also prove that every repetition of the sterilization process will show the intended effect. Documentation: Validation shall be documented to serve as a reference in case proof must be furnished that the sterilization process was correct. The intended effect means particularly the killing of the germs. It also includes that the goods are not damaged excessively and that the sterile packaging can serve its purpose after processing. (That is, for example, the packaging must not be wet after steam sterilization.) Validation of sterilization processes is to be seen as the documented proof that the sterilization process reproducibly achieves its intended effect.
verification dose	Dose of radiation applied to product units, or portions thereof, with the intention of validating or monitoring a sterilization dose. The verification dose is lower than the routine sterilization dose.
Worst Case	A condition or set of conditions encompassing upper and lower processing limits and circumstances, within standard operating procedures, which pose the greatest chance of product or process failure when compared to idealconditions. Such conditions do not necessarily induce product or process failure
X-rays	Penetrating electromagnetic radiation (photon) having a wavelength that is much shorter than that of visible light. These rays are usually produced by excitation of the electron field around certain nuclei. In nuclear reactions, it is customary to refer to photons originating in the nucleus as x-rays