An Overview on Bipolar Junction Transistor as a Sensor for X-ray Beams Used in Medical Diagnosis

Santos, Luiz A. P.

doi:10.3390/s22051923

Cited by 4 publications

(16 citation statements)

References 28 publications

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“…7 shows the MOSFET response to the X-ray pulses from the clinical equipment, and comparing with the standard sensor (Fig. 5) the similarity of behavior of both sensors can be noticed, it was expected [15]. The graph in Fig.…”

Section: Resultsmentioning

confidence: 69%

“…As the X-ray pulse time is constant (1.6 s) then the X-ray tube current, I XRT , corresponds to 62.5 mA and 125 mA, respectively. The current in the sensor is proportional to I XRT [11], [15]. Fig.…”

Section: Resultsmentioning

confidence: 99%

“…First, it was evaluated how is the signal behavior of a standard detector (10X5-6 ion chamber, Radical ® ) for the following X-ray tube parameters: 1600 ms exposure time for all experiments; 100 mAs and 200 mAs workloads; and varying the potential (kVp) from 52 kV up to 125 kV. The dose rate is proportional to the current signal produced by the sensor in each X-ray pulse [11], [15]. In each graph presented in the results each point corresponds to an average of 3 measurements.…”

Section: Measurement Proceduresmentioning

confidence: 99%

“…Due to numerous interactions, an electron rain is generated in the MOSFET as shown in Fig. 2 [15]. Therefore, instead of beam attenuation, there is a build-up cap effect, which makes the signal to be measured stronger, i.e., the current in the semiconductor device, i d (t), increases.…”

Section: Introductionmentioning

confidence: 99%

“…Fig.2. An illustration of numerous interactions generating the electron rain in a MOSFET where the device signal id(t) is the drain current[15].…”

mentioning

confidence: 99%

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A MOSFET-Based Method for Measuring Peak Kilovoltage (kVp) in Diagnostic X-Ray Beams

Cavalcanti

Santos

2022

IEEE Open J. Instrum. Meas.

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Peak kilovoltage (kVp) is an X-ray tube parameter that can influence the radiograph image quality and therefore, if the kVp is different from the nominal value, it can provide an unnecessary radiation dose to the patient if the examination has to be repeated. Therefore, some radiation protection institutions and health organizations (ICRP, IAEA) make recommendations to monitor kVp in medical diagnostic X-ray equipment in clinics and hospitals. There are some methods for measuring kVp in diagnostic X-ray beams, and the most common is the well-known two-sensor method, which uses two filters to attenuate the radiation beam, and it is based on the measurement of each identical sensor. The purpose of this article is to present a method for non-invasive measurement of kVp in medical diagnostic X-ray beams using the MOSFET device. Actually, MOSFET is well known as a detector for ionizing radiation dosimetry mainly in radiotherapy beams. Recently, MOSFET has also been used as dosimeter in diagnostic X-ray beams. In this work it will be shown a kVp measurement technique with MOSFET, which does not use the attenuation factor of the radiation filters, but instead takes advantage of the effect of the device package itself, known as the buildup cap effect. The results show that even with damage to the device exposed to radiation, MOSFET can be used as sensor for kVp measurement.

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Measurement Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Fig.2. An illustration of numerous interactions generating the electron rain in a MOSFET where the device signal id(t) is the drain current[15].…”

mentioning

confidence: 99%

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A MOSFET-Based Method for Measuring Peak Kilovoltage (kVp) in Diagnostic X-Ray Beams

Cavalcanti

Santos

2022

IEEE Open J. Instrum. Meas.

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An optocoupler-based method for dosimetry in low energy X-ray beams

Silva,

Gonçalves Filho,

Santos

2023

EPJ Web Conf.

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Semiconductor electronic devices have been used as detector in X-ray beams for decades, and the principle of operation is based on measuring the electrical current generated while such a device is under the ionizing radiation. Some devices that can be used are: photodiode, phototransistor, bipolar junction transistor, MOSFET, among others. In this work, a method based on an optocoupler device is presented for radiation dose real-time measurement in low-energy X-ray beam, which is used in medical radiology. Such an optoelectronic device has an LED and a phototransistor inside it, in general, for signal communication between two circuits that have to be electrically decoupled. Therefore, the light emitted by the LED excites the phototransistor. To develop an innovative method for radiation detection, the output signal from the phototransistor is used to feed back the current source of the LED so that the phototransistor is kept at a constant operating point by the photonic intensity of the LED, which is shielded from the ionizing radiation beam to be detected. When the optocoupler is irradiated an additional signal on the phototransistor is superimposed on the signal originated by the LED. Then, a time-integrated error signal is digitized and stored in real-time. Each step of the error signal is proportional to the accumulated radiation dose during the device exposure. This innovative method was tested under different conditions varying both peak kilovoltage (kV) and workload (mAs) in order to compare with results from other electronic devices. The experimental results showed that the optocoupler-based method for X-ray dose measurement works and consequently may become an option for X-ray dosimetry.

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An innovative detector for X-ray beams made of polyethylene terephthalate built in a 3D printer

Gomes,

Silva,

Santos

2023

EPJ Web Conf.

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3D printers have been increasingly used to create different objects and tools for the most diverse areas of knowledge. In this paper, we bring results of the response of an X-ray detector that was made on a 3D printer with polyethylene terephthalate glycol (PET-G) material. The manufacturing process has practically two steps, which consists of building a composite of two materials: a build-up cap made of PET-G; and a semiconductor film made of carbon-doped PET. The experimental methods performed were basically to compare the signals from the new PET-based X-ray detector with the signals from typical detectors. Clinical X-ray beams were used to test such an innovative detector. Two X-ray tube parameters were varied to analyse the response of the PET-based X-ray detector: potential (kV) and workload (mAs). The study points out the PET-G detector works and is easy to manufacture, although the signal is weaker than a typical semiconductor detector. Also, the noise signal is at least one order of magnitude smaller than silicon detectors. Furthermore, the density of PET is almost equivalent to human tissue, which is an advantage for dosimetry in phantoms. Finally, such a detector could become an option for X-ray beams in the near future.

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An Overview on Bipolar Junction Transistor as a Sensor for X-ray Beams Used in Medical Diagnosis

Cited by 4 publications

References 28 publications

A MOSFET-Based Method for Measuring Peak Kilovoltage (kVp) in Diagnostic X-Ray Beams

A MOSFET-Based Method for Measuring Peak Kilovoltage (kVp) in Diagnostic X-Ray Beams

An optocoupler-based method for dosimetry in low energy X-ray beams

An innovative detector for X-ray beams made of polyethylene terephthalate built in a 3D printer

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