Specific Definitions

DOE-STD-1121-98

(218Po, 214Pb, 214Bi, and 214Po) are of interest due to their potential for deposition in the lung, leading to

subsequent irradiation of lung tissue by alpha emissions from 218Po and 214Po.

Thoron and its short-lived progeny are continuously produced by the decay of 224Ra, a member of

the naturally occurring 232Th series. Thoron and 216Po have short half-lives: 56 s and 0.145 s, respectively.

Lead-212 and 212Bi are of interest due to the possibility of their being deposited in the lung and irradiating

tissue with alpha emissions.

2.3 SPECIFIC DEFINITIONS

activity median thermodynamic diameter (AMTD): "Fifty percent of the activity (thermodynamically

classified) in the aerosol is associated with particles of thermodynamic diameter (dth) greater than the

AMTD. A lognormal distribution of particle sizes is usually assumed." (ICRP 1994a)

annual effective dose equivalent (AEDE): The sum of effective dose equivalent from both the internal

and external irradiation of tissues and organs received in one calendar year. This definition is retained

from the 1989 version of DOE Order 5480.11 because records from that period include this quantity.

annual limit on exposure (ALE): The limit for potential alpha energy exposure to the progeny of 222Rn

or 220Rn, expressed in units of working level months (WLM) (ICRP 1981b). An implicit ALE for other

radionuclides is 2000 DAC-h.

annual limit on intake (ALI): The derived limit for the amount of radioactive material taken into the

body of an adult worker by inhalation or ingestion in a year. ALI is the smaller value of intake of a given

radionuclide in a year by Reference Man that would result in a committed effective dose equivalent of 5

rems (0.05 sievert) or a committed dose equivalent of 50 rems (0.5 sievert) to any individual organ or

tissue. 10 CFR 835.2 specifies that ALI values for intake by ingestion and inhalation of selected

radionuclides are based on Table 1 of Federal Guidance Report No. 11 (Eckerman et al. 1988). (10 CFR

835.2)

Note:The ALI for 222Rn and 220Rn progeny is most correctly expressed in joules (J) of potential alpha

energy (ICRP 1981b). Stochastic ALI (SALI) values and nonstochastic ALI (NALI) values result

from different dose limits. Intake of 1 SALI results in 5 rems committed effective dose equivalent,

while intake of 1 NALI results in 50 rems committed effective dose to the most highly exposed tissue

or organ.

appropriate blank: A sample, person, or phantom that is, ideally, identical in physicochemically and

radiologically significant ways with the sample, person, or phantom to be analyzed. (HPS N13.30-1996)

assess: For purposes of this Standard, to officially assign or record a dose number.

assigned protection factor (APF): The expected workplace level of respiratory protection that would be

provided by a properly functioning respirator or a class of respirators to properly fitted and trained users.

(ANSI Z88.2-1992)

bias: The deviation of a single measured value of a random variable from a corresponding expected

value, or a fixed mean deviation from the expected value that remains constant over replicated

measurements within the statistical precision of the measurement (synonymous with deterministic error,

fixed error, and systematic error). (HPS N13.30-1996)