ISO 20046:2019 放射線防護—電離放射線への曝露を評価するために蛍光in Situハイブリダイゼーション（FISH）転座アッセイを使用する実験室の性能基準 | ページ 6

3.1

absorbed dose

D

quantity of ionizing radiation energy imparted per unit mass of a specified material

3.2

acentric

terminal or interstitial chromosome fragment of varying size lacking a centromere, referred to as an excess acentric fragment when it is formed independently of a dicentric or centric ring chromosome aberration

3.3

anticoagulant

drug which prevents blood from clotting

3.4

background frequency/level

spontaneous frequency (or number) of chromosome aberrations recorded in a general population

3.5

buffy coat

layer of an anticoagulated blood sample after centrifugation that contains most of the white blood cells

3.6

calibration curve

graphical or mathematical description of the dose effect relation derived by the in vitro irradiation of blood samples to known absorbed doses

Note 1 to entry: The curve is used to determine, by interpolation, the absorbed radiation dose to a potentially exposed individual.

3.7

centromere

specialized constricted region of a chromosome that appears during mitosis and joins together the chromatid pair

3.8

chromatid

either of the two strands of a duplicated chromosome that are joined by a single centromere and separate during cell division to become individual chromosomes

3.9

chromosome

structure comprised of discrete packages of DNA and proteins that carries genetic information, which condense to form characteristically shaped bodies during nuclear division

3.10

chromosome aberration

change in the normal structure of a chromosome involving both chromatids of a single chromosome at the same locus as observed in metaphase

3.11

colcemid

alkaloid compound that inhibits spindle formation during cell division

Note 1 to entry: It is used to collect a large number of metaphase cells by preventing them from progressing to anaphase.

3.12

complex aberration

aberration involving three or more breaks in two or more chromosomes and is characteristically induced after exposure to densely ionizing radiation or high doses of sparsely ionizing radiation

3.13

confidence interval

range within which the true value of a statistical quantity lies with a specified probability

3.14

covariance

measure of the correlation of the variance between two (or more) dependent sets of data or parameters

3.15

decision threshold

value of the estimator of the measurand, which when exceeded by the result of the actual measurement using a given measurement procedure of a measurand quantifying a physical effect, one decides that the physical effect is present

Note 1 to entry: The decision threshold is defined such that in cases where the measurement result, y, exceeds the decision threshold, y*, the probability that the true value of the measurand is zero is less or equal to a chosen probability, α.

Note 2 to entry: If the result, y, is below the decision threshold, y*, the result cannot be attributed to the physical effect; nevertheless it cannot be concluded that it is absent.

3.16

detection limit

smallest true value of the measurand which ensures a specified probability of being detectable by the measurement procedure

Note 1 to entry: With the decision threshold (3.15) , the detection limit is the smallest true value of the measurand for which the probability of wrongly deciding that the true value of the measurand is zero is equal to a specified value, β, when, in fact, the true value of the measurand is not zero

3.17

dicentric

aberrant chromosome bearing two centromeres derived from the joining of parts from two broken chromosomes, generally accompanied by an acentric fragment

3.18

fluorescence in situ hybridization

FISH

technique that uses specific sequences of DNA as probes to particular parts of the genome, allowing the chromosomal regions to be highlighted or “painted” in different colours by attachment of various fluorochromes

3.19

fluorochrome

molecules that are fluorescent when appropriately excited

Note 1 to entry: They are used for FISH cytogenetics to highlight specific chromosomal regions.

3.20

genome equivalent

number of translocations that would be observed with all chromosomes painted, calculated from the number of translocations detected with a limited number of painted chromosomes

3.21

insertion

chromosome rearrangement in which a piece of one chromosome has been inserted within another chromosome

3.22

interphase

period of a cell cycle between the mitotic divisions

3.23

linear energy transfer

LET

radiation energy lost per unit length of path through a biological material

3.24

metaphase

stage of mitosis when the nuclear membrane is dissolved, the chromosomes condensed to their minimum lengths and aligned for division

3.25

protocol for aberration identification and nomenclature terminology

PAINT

terminology used in FISH analysis for describing chromosomal aberrations

3.26

precision

concept employed to describe dispersion of measurements with respect to a measure of location or central tendency

3.27

proficiency test

evaluation of participant performance against pre-established criteria by means of inter-laboratory comparisons

3.28

quality assurance

QA

planned and systematic actions necessary to provide adequate confidence that a process, measurement or service satisfies given requirements for quality

3.29

quality control

QC

part of quality assurance intended to verify that systems and components conform with predetermined requirements

3.30

radiation-induced translocation

among the observed translocations, the ones that can be attributed to a radiation exposure i.e. not translocations induced by other sources (e.g. age, lifestyle factors)

3.31

ring

aberrant circular chromosome resulting from the joining of two breaks within one chromosome

Note 1 to entry: Rings can be centric or acentric.

3.32

service laboratory

laboratory performing biological dosimetry measurements

3.33

stable aberration

aberration which is not lethal to the cell and can be passed on to daughter cells (e.g. simple translocation)

3.34

stable cell

cell without unstable aberrations, that may be entirely undamaged or contain stable type aberrations only, and are likely to survive division

3.35

translocation

stable chromosome aberration in which parts of two or more chromosomes are exchanged

3.36

unstable aberration

aberration which is lethal to the cell (e.g. dicentrics/centric rings/acentric fragments)