S. Hosokawa et al.: Radioprotection 2025, 60( 4), 370 – 372 371
Figure 1. Changes in technique before and after training( the shaded area indicates the recommended proper technique)( a) Speed( b) Distance. device( RaySafe X2). We recruited 12 senior students majoring in Radiological Technology. Each participant was instructed to perform surface contamination surveys of a 70 100 cm table covered with filter paper, once before training and once after. During these days, the participants were instructed regarding the proper technique, specifically maintaining a scanning speed of 3 – 5cms �1 and a probe-to-surface distance of approximately 1 cm. Before their second survey, the participants were shown a recorded data of their first technique. They then underwent training, during which their scanning speed and distance were displayed in real time. To determine whether the training significantly improved the technique, we used either a t-test or the Wilcoxon signed-rank test. P < 0.05 was considered statistically significant.
3 Results
At distances of ≥2 cm, the relationship between the OF sensor output and the distance was approximately an inverse. The corrected values obtained using the approximation equation derived from the 3 – 10 cm range exhibited a linear relationship with distance. This enabled the conversion of the OF sensor output into speed.
Figure 1 presents the results of each participant’ s contamination survey technique. The standard deviations, representing the variation during survey, are overlaid on the bar graphs. After training, the participants’ average scanning speed decreased from 4.70 to 3.45 cm s �1( p = 0.0091), and their average distance decreased from 1.16 to 0.90 cm( p = 0.0034). In addition, the variability( as revealed by the standard deviation) during surveys was significantly reduced after training: speed variation decreased from 1.23 to 0.876( p = 0.0034), and distance variation decreased from 4.10 to 3.14( p = 0.0066).
4
Discussion
Since the OF sensor output is theoretically expected to inversely correlate with distance( y = ax �1), the 3 – 10 cm range produced results that were closer to the theoretical value of b = �1 in the power-function y = ax b than the 2 – 10 cm range, with the 4 – 10 cm range showing further improvement. However, as distance increases, the signal strength diminishes and the signal-to-noise ratio decreases.
After establishing an environment for recording speed and distance, we evaluated the contamination survey techniques of the 12 participants. Although participants exhibited significant improvements in technique following training, they were already close to the proper technique before the training began. Because the participants were students unfamiliar with contamination survey techniques, we provided prior explanations of the proper methods. By selecting experienced workers who do not require preliminary explanations, it would be possible to more realistically assess the training effect.
Moreover, the variation in the survey technique during the contamination surveys showed a significant reduction post training, suggesting that the stability of their technique improved.
5 Conclusion
By examining a technique for recording the probe movement speed and the distance from the scanning surface, we found that combining a distance sensor with an OF sensor made it possible to achieve this goal. Furthermore, providing these values during training sessions helped participants employ proper techniques and achieve reduced variation during contamination surveys, resulting in more stable performances.
Acknowledgments
We would like to express our gratitude to the students of Hisa University who participated in this study.
Funding
This work was supported by JSPS KAKENHI Grant Number JP23K11914.
Conflicts of interest
The authors declare no conflicts of interest.
Data availability statement
The research data associated with this article is included within the article.