1. NAME AND TITLE
INREM II: Computer Implementation of Recent Models for Estimating the Dose Equivalent to
Organs of Man from an Inhaled or Ingested Radionuclide.
Oak Ridge National Laboratory, Oak Ridge, Tennessee.
3. CODING LANGUAGE AND COMPUTER
Fortran IV; IBM 370/3033.
4. NATURE OF PROBLEM SOLVED
INREM II reads dosimetric and metabolic information about the radionuclides in a chain and
calculates the resultant dose equivalent to various organs of a reference adult human following
inhalation or ingestion of the first (or parent) nuclide of the chain. The ICRP Task Group Lung Model
is used to estimate the deposition and retention of inhaled particulates and their absorption into the
blood and clearance into the GI tract. A four-segment model of the GI tract with first-order mass
transport and absorption of activity permits calculation of residence times of radionuclides in the tract
and the dynamics of their assimilation from that site. Residence times of activity in other organs are
computed from retention functions that are linear combinations of decaying exponential functions.
5. METHOD OF SOLUTION
The dose equivalent to a target organ is computed as the sum of contributions from each source organ in which radioactivity is assumed to be situated. This calculation utilizes a matrix of S-factors supplied by the user for the particular choice of source and target organs. Output permits the evaluation of crossfire components of dose when penetrating radiations are present.
The residence times of the radioactive daughters are calculated with consideration of their differential transfer among the body's compartments. This approach permits each nuclide in the chain to be cleared from the lungs, absorbed from the GI tract, and taken up and retained by other organs in accordance with its own properties.
Solution of the system and subsequent integration of the activity levels are accomplished using an
approach based on solving parts of the system in closed form and approximating certain continuous
transfers of activity by discrete counterparts.
6. RESTRICTIONS OR LIMITATIONS
7. TYPICAL RUNNING TIME
The sample problem executed in 2.19 minutes on the IBM 370/ 3033.
8. COMPUTER HARDWARE REQUIREMENTS
The code is operable on the IBM 370/3033 computer. It requires 236 K of storage.
9. COMPUTER SOFTWARE REQUIREMENTS
A Fortran H Extended compiler is required. The code uses standard I/O plus punch and log 16.
G. G. Killough, D. E. Dunning, Jr., J. C. Pleasant, "INREM II: A Computer Implementation of
Recent Models for Estimating the Dose Equivalent to Organs of Man from an Inhaled or Ingested
Radionuclide," NUREG/CR-0114, ORNL/NUREG/TM-84 (June 1978).
11. CONTENTS OF CODE PACKAGE
Included are the referenced document and one (1.2MB) DOS diskette which contains the source
codes and sample problem input and output.
12. DATE OF ABSTRACT
KEYWORDS: RADIONUCLIDES; MODEL MAN; INTERNAL DOSE; ISOTOPE INVENTORY