Development of a diverging collimator for environmental radiation monitoring in the industrial fields

Han, Dong-Hee; Lee, Seung-Jae; Kim, Jang-Oh; Kwon, Da-Eun; Lee, Hak-Jae; Baek, Cheol-Ha

doi:10.1016/j.net.2022.08.004

Cited by 2 publications

(2 citation statements)

References 15 publications

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“…Before evaluating the acquired images through simulation, we first checked the total counts of the acquired images based on previous research showing that detection of Ir-192 sources with scintillation cameras or gamma cameras is hampered by problems such as difficulty in collimation due to strong radioactivity and saturation of the electronics circuit ( Figure 2A ) ( Nagata et al, 2020 ). In addition, to evaluate the acquired images, vertical and horizontal profiles were made based on the maximum count, i.e., the pixel with the highest value in the image ( Figure 2B ), and the SNR was calculated using the following equation ( Han et al, 2022 ):

where

is the count of the signal at the profile peak and

is the count of the noise in the background ( Figure 2C ). Finally, we employed an analysis tool based on Python code to accurately calculate the FWHM and SNR.…”

Section: Methodsmentioning

confidence: 99%

Monte Carlo simulation study of an in vivo four-dimensional tracking system with a diverging collimator for monitoring radiation source (Ir-192) location during brachytherapy: proof of concept and feasibility

Oh,

Lee,

Kim

et al. 2024

Front. Physiol.

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Introduction: The aim of this study was to demonstrate the potential of an in vivo four-dimensional (4D) tracking system to accurately localize the radiation source, Iridium-192 (Ir-192) in high-dose rate brachytherapy.Methods: To achieve time-dependent 3D positioning of the Ir-192 source, we devised a 4D tracking system employing multiple compact detectors. During the system’s design phase, we conducted comprehensive optimization and analytical evaluations of the diverging collimator employed for detection purposes. Subsequently, we executed 3D reconstruction and positioning procedures based on the 2D images obtained by six detectors, each equipped with an optimized diverging collimator. All simulations for designing and evaluating the 4D tracking system were performed using the open-source GATE (v9.1) Monte Carlo platform based on the GEANT4 (v10.7) toolkit. In addition, to evaluate the accuracy of the proposed 4D tracking system, we conducted simulations and 3D positioning using a solid phantom and patient data. Finally, the error between the reconstructed position coordinates determined by the tracking system and the original coordinates of the Ir-192 radiation source was analyzed.Results: The parameters for the optimized diverging collimator were a septal thickness of 0.3 mm and a collimator height of 30 mm. A tracking system comprising 6 compact detectors was designed and implemented utilizing this collimator. Analysis of the accuracy of the proposed Ir-192 source tracking system found that the average of the absolute values of the error between the 3D reconstructed and original positions for the simulation with the solid phantom were 0.440 mm for the x coordinate, 0.423 mm for the y coordinate, and 0.764 mm for the z coordinate, and the average Euclidean distance was 1.146 mm. Finally, in a simulation based on data from a patient who underwent brachytherapy, the average Euclidean distance between the original and reconstructed source position was 0.586 mm.Discussion: These results indicated that the newly designed in vivo 4D tracking system for monitoring the Ir-192 source during brachytherapy could determine the 3D position of the radiation source in real time during treatment. We conclude that the proposed positioning system has the potential to make brachytherapy more accurate and reliable.

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where

is the count of the signal at the profile peak and

is the count of the noise in the background ( Figure 2C ). Finally, we employed an analysis tool based on Python code to accurately calculate the FWHM and SNR.…”

Section: Methodsmentioning

confidence: 99%

Monte Carlo simulation study of an in vivo four-dimensional tracking system with a diverging collimator for monitoring radiation source (Ir-192) location during brachytherapy: proof of concept and feasibility

Oh,

Lee,

Kim

et al. 2024

Front. Physiol.

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“…Despite the numerous clinical applications of gamma camera systems and their advantages, radiation oncology is not being actively investigated as compared with other medical fields, such as nuclear medicine. Although some studies pertaining to the use of gamma cameras for detecting brachytherapy radiation sources have been conducted, the frequency of such studies is relatively low compared with those of other fields [13][14][15][16][17][18][19][20][21]. Furthermore, research on gamma camera systems for brachytherapy has predominantly focused on pinhole collimators, whereas studies pertaining to other collimator types are scarce.…”

Section: Introductionmentioning

confidence: 99%

Feasibility study of real-time imaging of an Ir-192 source using compact gamma camera with curved diverging collimator for brachytherapy

Oh,

Jeong,

Choi

et al. 2024

J. Inst.

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Brachytherapy is a treatment method that requires the accurate positioning of a radioactive source to deliver high doses to a tumor while minimizing exposure to surrounding tissues. Herein, we propose a compact gamma camera system based on a diverging collimator for real-time source positioning during brachytherapy. In the process of developing and fabricating such a gamma camera system, Monte Carlo simulations for diverging and pinhole collimators are performed under conditions that are similar to the actual detection environment, with the camera-to-source distance set at 50 cm to verify the feasibility of the gamma camera. Full width at half maximum (FWHM) and signal-to-noise ratio (SNR) values are analyzed based on the horizontal and vertical profiles at each location as the source shifts stepwise from the center to the right and diagonal direction. On average, the diverging collimator had FWHM values of 18 and 13 mm and SNR values of 30 and 31, while the pinhole collimator had FWHM values of 26 and 25 mm and SNR values of 47 and 46 when profiled horizontally and vertically. The diverging collimator has a lower SNR than pinhole collimator but performs better in terms of spatial resolution. Additionally, to test the performance of the manufactured gamma camera, the distance between the camera and the source was set to 100 cm and an experiment was conducted. The experimental results exhibit a trend similar to the simulation. Numerically, the average FWHM value were 39 mm in the vertical direction and 71 mm in the horizontal direction. Additionally, the average SNR values were 27 for the vertical direction and 17 for the horizontal direction. Based on these results, we confirm the possibility of Ir-192 source imaging.

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Development of a diverging collimator for environmental radiation monitoring in the industrial fields

Cited by 2 publications

References 15 publications

Monte Carlo simulation study of an in vivo four-dimensional tracking system with a diverging collimator for monitoring radiation source (Ir-192) location during brachytherapy: proof of concept and feasibility

Monte Carlo simulation study of an in vivo four-dimensional tracking system with a diverging collimator for monitoring radiation source (Ir-192) location during brachytherapy: proof of concept and feasibility

Feasibility study of real-time imaging of an Ir-192 source using compact gamma camera with curved diverging collimator for brachytherapy

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