A new positron-gamma discriminating phoswich detector based on wavelength discrimination (WLD)

Ullah, Muhammad Nasir; Park, Chansun; Pratiwi, Eva; Kim, Chanho; Choi, Hojong; Yeom, Jung Yeol

doi:10.1016/j.nima.2019.162631

Cited by 15 publications

(8 citation statements)

References 32 publications

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“…Although many studies have successfully distinguished positrons and γ-rays by applying PSD techniques 3,13 or wavelength filters 23 to signals obtained from the phoswich detectors, some γ-rays can still be falsely discriminated as positrons in a phoswich detector (i.e., false positron). For example, some of γ-rays scattered in one scintillator (i.e., Compton scattering) can subsequently deposit the rest of its energy in the other scintillator layer.…”

Section: Introductionmentioning

confidence: 99%

Improvement of phoswich detector‐based β+/γ‐ray discrimination algorithm with deep learning

Kim

Lee

et al. 2023

Medical Physics

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BackgroundPositron probes can accurately localize malignant tumors by directly detecting positrons emitted from positron‐emitting radiopharmaceuticals that accumulate in malignant tumors. In the conventional method for direct positron detection, multilayer scintillator detection and pulse shape discrimination techniques are used. However, some γ‐rays cannot be distinguished by conventional methods. Accordingly, these γ‐rays are misidentified as positrons, which may increase the error rate of positron detection.PurposeTo analyze the energy distribution in each scintillator of the multilayer scintillator detector to distinguish true positrons and γ‐rays and to improve the positron detection algorithm by discriminating true and false positrons.MethodsWe used Autoencoder, an unsupervised deep learning architecture, to obtain the energy distribution data in each scintillator of the multilayer scintillator detector. The Autoencoder was trained to separate the combined signals generated from the multilayer scintillator detector into two signals of each scintillator. An energy window was then applied to the energy distribution obtained using the trained Autoencoder to distinguish true positrons from false positrons. Finally, the performance of the proposed method and conventional positron detection algorithm was evaluated in terms of the sensitivity and error rate for positron detection.ResultsThe energy distribution map obtained using the trained Autoencoder was proven to be similar to that of the simulated results. Furthermore, the proposed method demonstrated a 29.79% (+0.42%p) increase in positron detection sensitivity compared to the conventional method, both having an equal error rate of 0.48%. However, when both methods were set to have the same sensitivity of 1.83%, the proposed method had an error rate that was 25.0% (−0.16%p) lower than that of the conventional method.ConclusionsWe proposed and developed an Autoencoder‐based positron detection algorithm that can discriminate between true and false positrons with a smaller error rate than conventional methods. We verified that the proposed method could increase the positron detection sensitivity while maintaining a low error rate compared to the conventional method. If the proposed algorithm is implemented in handheld positron detection probes or cameras, diseases such as cancers can be more accurately localized in a shorter time compared with using traditional methods.

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Section: Introductionmentioning

confidence: 99%

Improvement of phoswich detector‐based β+/γ‐ray discrimination algorithm with deep learning

Kim

Lee

et al. 2023

Medical Physics

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“…Recently, ultrasound systems are widely used to evaluate the performances such as pulse-echo responses and cell responses [1]. The systems are composed of the transmitter and receiver with transducers [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Novel dual-resistor-diode limiter circuit structures for high-voltage reliable ultrasound receiver systems

Choi¹

2022

THC

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BACKGROUND: The limiters have been used to protect the ultrasound receivers because of the inherent characteristic of the transducers which are required to use the high voltage excitation to obtain the reasonable echo signal amplitudes. OBJECTIVE: Among the variety of the limiters, the performances of discharge voltage degradation from the limiters gradually deteriorate the whole ultrasound systems according to the applied voltages of the ultrasonic transducers. This could cause the ultrasound systems to be unreliable for the long-term operations, resulting in possibly breaking the receiver systems. METHODS: Designed limiters were evaluated with insertion loss, total harmonic distortion, and pulse-echo responses with the ultrasound transducer devices. RESULTS: Designed new dual-resistor-diode limiters exhibited greater and faster suppression of the pulse width (1.15 V and 6.1 μs) for high-voltage signals. CONCLUSIONS: Our proposed dual-resistor-diode limiter could be one of the potential candidates for reliable ultrasound receiver system.

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“…Ultrasound machines are typically used to check the conditions of patients or cracks in steel for non-destructive testing or applying acoustic power for clinical or surgical purposes [1,2]. Compared with computed X-ray, tomography, positron emission tomography, and magnetic resonant imaging, ultrasound machines are relatively inexpensive imaging modalities [2][3][4][5]. Currently, mobile ultrasound machines are widely used for emergency rooms in hospitals or outdoor activities such as sports owing to advanced semiconductor technologies [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Fisheye lens design for solar-powered mobile ultrasound devices

Ryu

Choi

2022

THC

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BACKGROUND: Compared to benchtop ultrasound machines, mobile ultrasound machines require portable batteries when acquiring information regarding human tissues during outdoor activities. OBJECTIVE: A novel fisheye lens type was designed to address the charging issue where it is difficult to constantly track the sun. This method does not require the use of a mechanical motor that constantly tracks the sun to charge the portable batteries. METHODS: To obtain an optical solar power system, the numerical aperture (NA) and field angle must be increased. Therefore, we use the fisheye lens with the largest field angle. RESULTS: The NA of the designed fisheye lens system reaches 0.75, allowing light collection of approximately ± 48∘. Additionally, the efficiency ratio of the central and surrounding areas also satisfies more than 80% at a field angle of 85∘ and more than 70% at field angles of 85∘ to 90∘, respectively. CONCLUSIONS: We designed a novel fisheye lens for solar-powered mobile ultrasound machines used outdoors.

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A new positron-gamma discriminating phoswich detector based on wavelength discrimination (WLD)

Cited by 15 publications

References 32 publications

Improvement of phoswich detector‐based β+/γ‐ray discrimination algorithm with deep learning

Improvement of phoswich detector‐based β+/γ‐ray discrimination algorithm with deep learning

Novel dual-resistor-diode limiter circuit structures for high-voltage reliable ultrasound receiver systems

Fisheye lens design for solar-powered mobile ultrasound devices

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