Radioprotection 2025, 60( 4), 370 – 372 © S. Hosokawa et al., Published by EDP Sciences, 2025 https:// doi. org / 10.1051 / radiopro / 2025009
Available online at: www. radioprotection. org
ARTICLE
Evaluating the Educational Effectiveness of Surface Radioactive Contamination Survey Techniques
S. Hosokawa 1,*, A. Nakamura 2, H. Ose 2, M. Osanai 1, R. Mori 1, K. Okuda 1, T. Tsujiguchi 3, T. Tomisawa 4 and Y. Takahashi 1
1 Department of Radiation Science. 2 Department of Radiological Technology. 3 Education Center for Disaster and Radiation Emergency Medicine. 4 Department of Nursing Science, Hirosaki University, 66-1, Honcho, Hirosaki, Aomori, 036-8564, Japan.
Received: 22 February 2025 / Accepted: 7 March 2025
Abstract – In this study, we evaluated the educational effectiveness of training by reviewing recorded data on contamination survey techniques and real-time display feedback. An optical flow( OF) sensor and a distance sensor were used to measure the speed and distance, respectively. The sensors were mounted on a radiation measuring device, and the contamination survey techniques of the 12 participants were recorded. The recorded data and real-time technique feedback was used to conduct training, after which the participants performed contamination surveys once more. Speed and distance both significantly decreased after training, with speed dropping from 4.70 to 3.45 cm s �1 and distance decreasing from 1.16 to 0.90 cm. Additionally, variations during surveys showed a significant reduction.
Keywords: optical flow / education / radioactive contamination survey
1 Introduction
Surface contamination surveys are typically performed by workers using Geiger – Müller survey meters. To reliably detect contamination, it is important to bring the probe close to the surface and scan slowly and carefully. Previous studies have demonstrated that when the probe is moved more slowly, differences in distance have a smaller impact on detection( Yamanishi and Sugiura, 2009). It has also been demonstrated that for low-energy beta-emitting radionuclides, such as C-14, maintaining a 5 mm gap between the detector and the source makes it sufficiently possible to detect contamination levels around the regulatory standard of 40 Bq / cm 2 for controlled areas, which is based on Japanese regulations( Abe et al., 2010). If the appropriate techniques are employed, contamination surveys can be conducted with sufficient sensitivity. As for previous research focusing on training contamination surveys, Onuma et al.( 2012) developed a PC software program that simulated probe operations via mouse movements to highlight differences in the scanning techniques of novices and experts. Tomisawa et al.( 2023) conducted contamination survey training in a virtual reality environment and reported that its educational effect was equivalent to that of in-person training. Nonetheless, non-negligible discrepancies
* Corresponding author: shosokawa @ hirosaki-u. ac. jp between simulations and real-world settings exist, and the training often remains a one-time exercise. In this study, we examined a method that enables continuous training and is applicable to daily operations and verified its educational effectiveness.
2 Materials and methods 2.1 Acquisition of correction factors for speed estimation For speed estimation, we employed an optical flow( OF) sensor( ThoneFlow-3901UY). We connected the OF sensor and a distance sensor( VL6180X) to a microcontroller board( ESP32 DW3000). The distance from the scanning surface was varied from 1 to 10 cm, and at each distance, the movement speed of the microcontroller board was varied from 1 to 10 cm s �1, resulting in 100 different conditions. From the relationship between distance and output, we derived correction factors that were applied to the outputs to obtain distance-independent values.
2.2 Evaluation of the educational effect
Based on the above considerations, we attached the OF sensor to an appropriate position on the radiation measurement
This is an Open Access article distributed under the terms of the Creative Commons Attribution License( https:// creativecommons. org / licenses / by / 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.