Related Experiment Video
Updated: Oct 19, 2026

Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification (ADCI) and Dose Estimation
Published on: September 4, 2017
A Lightweight Python-based Monte Carlo Framework for Visualizing Energy-dependent Dose Calibrator Response: A Nuclear
Anil Kumar Pandey1, Shanshila Rayamajhi1, Jagrati Chaudhary1
1Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.
Purpose:
Trainees often have limited understanding of radionuclide dose-calibrator physics because access to radioactive materials is restricted by radiation-safety requirements, and the complexity of established Monte Carlo (MC) platforms can present a barrier to early learning. We present a lightweight, Python-based MC simulation framework designed to visualize energy-dependent photon transport and ionization-chamber response for nuclear medicine education.
Materials And Methods:
A spherical gas-filled ionization chamber (radius 5 cm) was modelled. Photon free-path lengths were sampled from exponential attenuation distributions; deposited energy was assigned via a Beta-distributed stochastic transfer fraction (biased toward partial deposition). Ionization yield was estimated assuming 33.97 eV is required to produce one ion pair. Three clinically representative radionuclides - 99mTc (140 keV, μ = 0.030 cm-1), 131I (364 keV, μ = 0.015 cm-1), and 18F (511 keV, μ = 0.011 cm-1) - were each simulated with 100,000 independent photon histories.
Results:
Intrinsic efficiency decreased monotonically with photon energy: 13.65% (99mTc), 7.01% (131I), and 5.25% (18F). Median deposited energy increased from 37.16 keV to 95.87 keV and 132.07 keV; mean ion-pair yield rose from 1180, 3046, and 4254. Detector response increased nonlinearly from 161 to 214 and 223 ion pairs per emitted photon. All trends were consistent with exponential attenuation theory.
Conclusions:
The framework reproduces first-order ionization-chamber physics without specialist software or radioactive sources. Its transparency, rapid execution, and interactive visualizations make it well suited for classroom demonstrations and self-directed nuclear medicine physics training, while its explicit limitations underscore the gap between educational modelling and clinical-grade Monte Carlo simulation.
Related Concept Videos
Positron Emission Tomography
One of the main requirements of a PET scan is a positron-emitting radioisotope, which is produced in a cyclotron and then attached to a substance used by the part of the body being...
Radiation: Applications
The average...
Radioactivity and Nuclear Equations
A nuclide of an element has a specific number of protons and...
Dose-Response Relationship: Overview
Radiation Pressure: Problem Solving
The average value of the rate of momentum transfer divided by the absorbing area represents the average force per...
Dose-Response Relationship: Potency and Efficacy

