scholarly journals Preliminary investigation on performance of photodiode sensor as a dosimeter

2021 ◽  
Vol 10 (1) ◽  
pp. 4-10
Author(s):  
Y. Md Radzi ◽  
N. Zulkafli ◽  
A. Omar
Keyword(s):  
Preliminary Investigation ◽  
Cost Effective ◽  
Tube Voltage ◽  
Linear Coefficient ◽  
Current Time ◽  
Energy Dependency ◽  
Tube Current ◽  
On Chip ◽  
Ionizing Radiation Exposure ◽  
Large Capacitance

Radiation dosimetry in the health and medicine field is crucial to ensure there is no unnecessary ionizing radiation exposure to patients and personnel. While various types of semiconductor dosimeters are available, photodiode sensors are seen as a reliable and cost-effective immediate dosimeter. This study investigates the capabilities of a monolithic photodiode with an on-chip trans-impedance amplifier as a dosimeter in diagnostic radiology. A photodiode sensor covered with black insulation tape is irradiated with the diagnostic x-ray of potential in range between 40 to 90 kV with constant tube current-time product of 50 mAs at 60 cm source-to-detector distance (SDD). Exposures of different tube current at the range of 10 to 250 mA with a constant tube voltage of 70 kVp at the same setup are made. The photodiode sensor connected to the electrometer gives out readings in the millivolt (mV), and the output of the photodiode and semiconductor detector is recorded. The photodiode’s energy dependency, reproducibility, dose response, and distance dependency were evaluated as the capabilities of the photodiode to be used as a dosimeter. For energy dependency, it shows a linearity of 0.9458, while the response to increasing tube current with a constant tube voltage shows the R2 of 0.912. The photodiode shows good dependency on the tube voltage and tube current. Other than that, it also showed a linear coefficient of 0.5138 for distance dependence which is considered as a good linearity fit value for a photodiode as initial performance. However, its reproducibility is poor due to its large capacitance. This monolithic photodiode with an on-chip trans-impedance amplifier has demonstrated good results for energy dependency but poor results for reproducibility. However, the photodiode can be improvised in the future to ensure it is suitable as a dosimeter.

scholarly journals Studies on the radiation dose, image quality and low contrast detectability from MSCT abdomen by using low tube voltage

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
A. Mokhtar ◽  
Z. A. Aabdelbary ◽  
A. Sarhan ◽  
H. M. Gad ◽  
M. T. Ahmed
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Statistical Significance ◽  
Image Noise ◽  
Tube Voltage ◽  
Current Time ◽  
Low Contrast ◽  
Low Tube Voltage ◽  
Tube Current ◽  
Noise Ratio

Abstract Background To study radiation dose, image quality and low-contrast cylinder detectability from multislice CT (MSCT) abdomen by using low tube voltage using the American College of Radiology (ACR) phantom. The ACR phantom (low-contrast module) was scanned with 64 MSCT scanner (Brilliance, Philips Medical System, Eindhoven, Netherlands) with 80 and 120 KVP, utilizing different tube current time product (mAs) range from 50 to 380 mAs. The image noise (SD), signal to noise ratio, contrast-to-noise ratio (CNR), and scores of low contrast detectability were assessed for every image respectively. Results From images analyses, the noise essentially increased with the use of low tube voltage. The CNR was 0.94 ± 0.27 at 120 KVP, and CNR was 0.43 ± 0.22 at 80 KVP. However, with the same dose, there were no differences of statistical significance in scores of low-contrast detectability between 120 KVP at 300mAs and 80 KVP at (200–380) mAs (p > 0.05). At 300 mAs, the CTDIvol obtained at 80 KVP was about 29% of that at 120 KVP. The CTDIvol obtained at 80 KVP were decreased from 5% at 50 mAs, to 37% at 380 mAs. Conclusions There is a possibility to decrease exposure of radiation virtually by reducing KVP from 120 to 80 KVP in examination of abdominal CT when the high tube current is used, though increasing image noise at low tube voltage.

RADIATION DOSE DISTRIBUTION OF A PLAIN RADIOGRAPHY ROOM AND COMPUTED TOMOGRAPHY ROOM IN A VETERINARY HOSPITAL

2019 ◽  
Vol 187 (2) ◽  
pp. 243-248
Author(s):  
Kuan-Sheng Chen ◽  
Ying-Hsiang Chou ◽  
Ruey-Shyuan Wu ◽  
Wei-Ming Lee ◽  
Yeu-Sheng Tyan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Radiation Safety ◽  
Plain Radiography ◽  
Dose Limit ◽  
Tube Voltage ◽  
Current Time ◽  
Tube Current ◽  
Control Rooms ◽  
Veterinary Hospital

Abstract Thermoluminescent dosemeters (TLDs) were attached to the walls of a plain radiography room and a computed tomography (CT) room, control rooms and corridors to measure the radiation dose. The types of animals scanned and scan parameters were analysed. Dogs and cats accounted for the largest proportion of animals, a combined total of 96.0%. Distributions of tube voltage and tube current-time product are presented. In the CT room, the dose at the angle of the gantry opening was higher than that on either side of the gantry. The study developed equations that may be useful to assess the dose for staff standing in radiography rooms. The personal annual doses for the controlled and uncontrolled areas were lower than the recommended dose limit. The annual doses for personnel and nonworkers were also within the acceptable level for radiation safety.

Optimisation of CT scan parameters to increase the accuracy of gross tumour volume identification in brain radiotherapy

2020 ◽  
pp. 1-5
Author(s):  
Kosar Estak ◽  
Mohammad Mohammadzadeh ◽  
Nahideh Gharehaghaji ◽  
Tohid Mortezazadeh ◽  
Rahim Khatyal ◽  
...  
Keyword(s):  
Image Quality ◽  
Tumour Volume ◽  
Standard Protocol ◽  
Gross Tumour Volume ◽  
Tube Voltage ◽  
Current Time ◽  
Low Contrast ◽  
Brain Radiotherapy ◽  
Tube Current ◽  
Tube Current Time Product

Abstract Aim: This study aimed to optimise computed tomography (CT) simulation scan parameters to increase the accuracy for gross tumour volume identification in brain radiotherapy. For this purpose, high-contrast scan protocols were assessed. Materials and methods: A CT accreditation phantom (ACR Gammex 464) was used to optimise brain CT scan parameters on a Toshiba Alexion 16-row multislice CT scanner. Dose, tube voltage, tube current–time and CT dose index (CTDI) were varied to create five image quality enhancement (IQE) protocols. They were assessed in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and noise level and compared with a standard clinical protocol. Finally, the ability of the selected protocols to identify low-contrast objects was examined based on a subjective method. Results: Among the five IQE protocols, the one with the highest tube current–time product (250 mA) and lowest tube voltage (100 kVp) showed higher CNR, while another with a tube current–time product of 150 mA and a tube voltage of 135 kVp had improved SNR and lower noise level compared to the standard protocol. In contouring low-contrast objects, the protocol with the highest milliampere and lowest peak kilovoltage exhibited the lowest error rate (1%) compared to the standard protocol (25%). Findings: CT image quality should be optimised using the high-dose parameters created in this study to provide better soft tissue contrast. This could lead to an accurate identification of gross tumour volume recognition in the planning of radiotherapy treatment.

scholarly journals 3D printed microfluidic lab-on-a-chip device for fiber-based dual beam optical manipulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haoran Wang ◽  
Anton Enders ◽  
John-Alexander Preuss ◽  
Janina Bahnemann ◽  
Alexander Heisterkamp ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Single Cells ◽  
Lab On A Chip ◽  
Cost Effective ◽  
Optical Manipulation ◽  
Hydrodynamic Focusing ◽  
Trapping Region ◽  
Dual Beam ◽  
3D Printed ◽  
On Chip

Abstract3D printing of microfluidic lab-on-a-chip devices enables rapid prototyping of robust and complex structures. In this work, we designed and fabricated a 3D printed lab-on-a-chip device for fiber-based dual beam optical manipulation. The final 3D printed chip offers three key features, such as (1) an optimized fiber channel design for precise alignment of optical fibers, (2) an optically clear window to visualize the trapping region, and (3) a sample channel which facilitates hydrodynamic focusing of samples. A square zig–zag structure incorporated in the sample channel increases the number of particles at the trapping site and focuses the cells and particles during experiments when operating the chip at low Reynolds number. To evaluate the performance of the device for optical manipulation, we implemented on-chip, fiber-based optical trapping of different-sized microscopic particles and performed trap stiffness measurements. In addition, optical stretching of MCF-7 cells was successfully accomplished for the purpose of studying the effects of a cytochalasin metabolite, pyrichalasin H, on cell elasticity. We observed distinct changes in the deformability of single cells treated with pyrichalasin H compared to untreated cells. These results demonstrate that 3D printed microfluidic lab-on-a-chip devices offer a cost-effective and customizable platform for applications in optical manipulation.

Predicting relapse in schizophrenia: the development and implementation of an early signs monitoring system using patients and families as observers, a preliminary investigation

1989 ◽  
Vol 19 (3) ◽  
pp. 649-656 ◽  
Author(s):  
Max Birchwood ◽  
Jo Smith ◽  
Fiona Macmillan ◽  
Bridget Hogg ◽  
Rekha Prasad ◽  
...  
Keyword(s):  
Secondary Prevention ◽  
Monitoring System ◽  
Preliminary Investigation ◽  
Psychometric Evaluation ◽  
Cost Effective ◽  
Self Report ◽  
Prodromal Symptoms ◽  
Considerable Potential ◽  
Early Signs ◽  
Pilot Investigation

SynopsisRecognition of prodromal symptoms of schizophrenia offers the potential of early intervention to avert relapse and re-hospitalization (Carpenter & Heinrichs, 1983). The present study investigated how a strategy to detect prodromal signs might be effectively applied in the clinical setting. A standard monitoring system was developed involving completion of a new early signs scale (ESS) measuring changes in key symptoms phenomenologically (self-report) and behaviourally (observer report). The ESS was subject to rigorous psychometric evaluation and tested in a prospective pilot investigation. The ESS reliably identified early signs and predicted relapse with an overall accuracy of 79%. Several different patterns of relapse were identified. Observer reports compensated for loss of insight in some patients. In two cases where early signs indices were detected, prompt increases in medication appeared to arrest relapse and avert readmission. The ESS offers itself as a reliable, valid and administratively feasible measure and demonstrates considerable potential as a cost-effective procedure for secondary prevention.

scholarly journals Recent Advances in Hearing Aid Technology-A Review

2021 ◽  
Vol 9 (VI) ◽  
pp. 3427-3429
Author(s):  
Animita Das
Keyword(s):  
Hearing Aids ◽  
Hearing Aid ◽  
Cost Effective ◽  
System On Chip ◽  
Audio Signals ◽  
Technology System ◽  
The People ◽  
Chip Technology ◽  
On Chip ◽  
System 1

Hearing aids are electroacoustic gadgets commonly worn in or behind the ear and are intended to enhance the speech Nowadays hearing aids support various application unlike the traditional ones such that it can act like headphones streaming audio signals from internet-enabled devices connected wirelessly via Bluetooth. This paper aims to review the various advancements in the hearing aid technology. System on chip technology of the microcontroller have been used in various studies to develop and design an effective hearing assistant device and help the people with hearing impairment to lead a normal life. Ten articles have been reviewed for the study and it can be concluded that IoT is the future for an efficient, cost effective hearing assistive system [1]

Wearout and Variation Tolerant Source Synchronous Communication for GALS Network-on-Chip Design

2014 ◽  
pp. 399-419
Author(s):  
Alessandro Strano ◽  
Carles Hernández ◽  
Federico Silla ◽  
Davide Bertozzi
Keyword(s):  
Cost Effective ◽  
Internal Communication ◽  
Synchronous Communication ◽  
Chip Design ◽  
Networks On Chip ◽  
Switch Architecture ◽  
Network Operation ◽  
Placement And Routing ◽  
Delay Variations ◽  
On Chip

In the context of multi-IP chips making use of internal communication paths other than the traditional buses, source synchronous links for use in multi-synchronous Networks-on-Chip (NoCs) are becoming the most vulnerable points for correct network operation and therefore need to be safeguarded against intra-link delay variations and signal misalignments. The intricacy of matching link net attributes during placement and routing and the growing role of process parameter variations in nanoscale silicon technologies, as well as the deterioration due to the ageing of the chip, are the root causes for this. This chapter addresses the challenge of designing a timing variation and layout mismatch tolerant link for synchronizer-based GALS NoCs by implementing a self-calibration mechanism. A timing variation detector senses the misalignment, due to process variation and wearout, between data lines with themselves and with the transmitter clock routed with data in source synchronous links. Then, a suitable delayed replica of the transmitter clock is selected for safe sampling of misaligned data. This chapter proves the robustness of the link in isolation with respect to a detector-less link, also addressing integration issues with the downstream synchronizer and switch architecture, proving the benefits in a realistic experimental setting for cost-effective NoCs.

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