A simulation study of radon and thoron discrimination problem in case-control studies
Related Experiment Video
Updated: Jun 21, 2026

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level
Published on: June 6, 2018
Kazutaka Doi1, Shinji Tokonami, Hidenori Yonehara
1Regulatory Sciences Research Group, National Institute of Radiological Sciences, Chiba-shi, Chiba, Japan. kazutaka@nirs.go.jp
Abstract:
In most countries, radon is the dominant contributor among natural radiation sources to the radiation exposure dose of the general population. Numerous case-control studies of residential radon and lung cancer have been conducted using passive radon (Rn-222) detectors. These studies showed that radon may increase lung cancer risk, but most of them did not show a significant risk. Recently it was shown that the readings of passive radon detectors that do not employ thoron (Rn-220) discrimination techniques are affected by thoron. Therefore, we conducted a simulation study to evaluate the possible effect of thoron interference on the estimation of radon-related lung cancer risk. Various assumptions were made based on the number of cases, matching ratio, baseline risk, true radon-related risk, distribution of radon and thoron concentrations, correlation between radon and thoron, and radon detectors. The results suggested that in certain circumstances thoron interference in radon measurements resulted in an approximately 90% downward bias. In addition, the magnitude of the bias increased as the geometric mean and geometric standard error of radon concentration decreased and those of thoron increased. In order to resolve this problem, it is necessary to use passive radon detectors with thoron discrimination techniques in epidemiological studies.
Related Concept Videos
Strategies for Assessing and Addressing Confounding
Confounding can be addressed at both the design phase of a study and through analytical methods after data...
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Hazard Ratio
For example, in a clinical trial evaluating a...
Randomized Experiments
Simple randomization
Simple...
Radiation Pressure: Problem Solving
The average value of the rate of momentum transfer divided by the absorbing area represents the average force per...
Comparing the Survival Analysis of Two or More Groups

