Determining optimum wavelength of ultraviolet rays to pre-exposure of non-uniformity error correction in Gafchromic EBT2 films

Abstract Gafchromic films have been used to measure X-ray doses in diagnostic radiology such as computed tomography. The double-exposure technique is used to correct non-uniformity error of Gafchromic EBT2 films. Because of the heel effect of diagnostic x-rays, ultraviolet A (UV-A) is intended to be used as a substitute for x-rays. When using a UV-A light-emitting diode (LED), it is necessary to determine the effective optimal UV wavelength for the active layer of Gafchromic EBT2 films. This study evaluated the relation between the increase in color density of Gafchromic EBT2 films and the UV wavelengths. First, to correct non-uniformity, a Gafchromic EBT2 film was pre-irradiated using uniform UV-A radiation for 60 min from a 72-cm distance. Second, the film was irradiated using a UV-LED with a wavelength of 353-410 nm for 60 min from a 5.3-cm distance. The maximum, minimum, and mean ± standard deviation (SD) of pixel values of the subtraction images were evaluated using 0.5 inches of a circular region of interest (ROI). The highest mean ± SD (8915.25 ± 608.86) of the pixel value was obtained at a wavelength of 375 nm. The results indicated that 375 nm is the most effective and sensitive wavelength of UV-A for Gafchromic EBT2 films and that UV-A can be used as a substitute for x-rays in the double-exposure technique.

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Ultraviolet ray irradiation duration for the pre-exposure of Gafchromic EBT2

Polish Journal of Medical Physics and Engineering ◽

10.2478/pjmpe-2018-0026 ◽

2018 ◽

Vol 24 (4) ◽

pp. 189-193

Author(s):

Toshizo Katsuda ◽

Rumi Gotanda ◽

Tatsuhiro Gotanda ◽

Takuya Akagawa ◽

Nobuyoshi Tanki ◽

...

Keyword(s):

Uv Light ◽

Light Emitting Diode ◽

Region Of Interest ◽

Density Change ◽

Light Emitting ◽

X Ray ◽

Zero Values ◽

Pixel Value ◽

Ultraviolet Ray ◽

Gafchromic Ebt2 Film

Abstract The strength and density change of the ultraviolet (UV) ray of Gafchromic EBT2 were investigated. Previous studies suggested that UV-A rays can be substituted for the x-ray double-exposure technique to correct Gafchromic EBT2’s non-uniformity error. In this study, we aimed to determine the appropriate strength of UV-A rays for irradiating an active layer that would correct the non-uniformity error of Gafchromic EBT2. UV-A rays with a wavelength of 375 nm were used to irradiate Gafchromic EBT2 in various durations, and the resulting density change was investigated. To correct Gafchromic EBT2’s non-uniformity error, a pre-irradiation with a UV-A lamp was conducted at a distance of 72 cm for 30 min. To determine the most appropriate irradiation duration, a UV light-emitting diode generating UV-A of 375 nm was used to irradiate the Gafchromic EBT2 film with varying durations of 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 min at a distance of 5.3 cm. A 12.7 diameter region of interest was set by the irradiation area, and a histogram of pixel values was created. The condition options were decided based on two important requirements: 1) no zero values of the mode and seconds exist, and 2) the 1/10 value of the mode intersects both histogram sleeves. In the case of Gafchromic EBT2, the irradiation strength was 85.43 mJ/cm2 for one minute in which the pixel value of mean ± SD was 255.34 ± 213.29. The irradiation duration of 4 min was the border duration of the above two conditions. When a UV ray of 375 nm wavelength is used to irradiate Gafchromic EBT2 as a substitute for x-ray exposure, the 4-min pre-irradiation duration (341.74 mJ/cm2) is demonstrably sufficient.

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Evaluation of Static Performance of Optoelectronic Semiconductor Devices under X-Rays Irradiation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.173.1 ◽

2010 ◽

Vol 173 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Haider F. Abdul Amir ◽

Fuei Pien Chee

Keyword(s):

Ionizing Radiation ◽

Light Emitting Diode ◽

Optoelectronic Devices ◽

Third Party ◽

Infrared Light ◽

X Rays ◽

Total Ionizing Dose ◽

Light Emitting ◽

Static Performance ◽

Current Drives

In this research, optoelectronic devices consisted of an infrared light emitting diode and a phototransistor with no special handling or third party-packaging were irradiated to ionizing radiation utilizing x-rays. It was found that the devices under test (DUTs) undergo performance degradation in their functional parameters during exposure to x-rays. These damaging effects are depending on their current drives and also the Total Ionizing Dose (TID) absorbed. The TID effects by x-rays are cumulative and gradually take place throughout the lifecycle of the devices exposed to radiation.

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Making Image More Energy Efficient for OLED Smart Devices

Mobile Information Systems ◽

10.1155/2016/6575931 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Deguang Li ◽

Bing Guo ◽

Yan Shen ◽

Junke Li ◽

Yanhui Huang

Keyword(s):

Spatial Information ◽

Light Emitting Diode ◽

Region Of Interest ◽

Detection Algorithm ◽

Smart Devices ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

Battery Capacity ◽

Display Technology ◽

Energy Consuming

Now, more and more mobile smart devices are emerging massively; energy consumption of these devices has become an important consideration due to the limitation of battery capacity. Displays are the dominant energy consuming component of battery-operated devices, giving rise to organic light-emitting diode (OLED) as a new promising display technology, which consumes different power when displaying different content due to their emissive nature. Based on this property, we propose an approach to improve image energy efficiency on OLED displays by perceiving image content. The key idea of our approach is to eliminate undesired details while preserving the region of interest of the image by leveraging the color and spatial information. First, we use edge detection algorithm to extract region of interest (ROI) of an image. Next, we gradually change luminance and saturation of region of noninterest (NON-ROI) of the image. Then we perform detailed experiment and case study to validate our approach; experiment results show that our approach can save 22.5% energy on average while preserving high quality of the image.

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Comparison of Current–Voltage Response to Diagnostic X-rays of Five Light-Emitting Diode Strips

Applied Sciences ◽

10.3390/app10010200 ◽

2019 ◽

Vol 10 (1) ◽

pp. 200 ◽

Cited By ~ 1

Author(s):

Edrine Damulira ◽

Muhammad Yusoff ◽

Suharti Sulaiman ◽

Nur Zulkafli ◽

Nur Zulkifli ◽

...

Keyword(s):

Light Emitting Diode ◽

Low Cost ◽

Voltage Response ◽

White Led ◽

X Rays ◽

Light Emitters ◽

Light Emitting ◽

X Ray ◽

Reproducibility Study ◽

Current Voltage

Light-emitting diodes (LEDs) have miscellaneous applications owing to their low cost, small size, flexibility, and commercial availability. Furthermore, LEDs have dual applicability as light emitters and detectors. This study explores the current–voltage (C–V) response of LED strips exposed to diagnostic x-rays. Cold white, warm white, red, green, and blue LED strip colors were tested. Each strip consisted of 12 LED chips and was connected to a multimeter. The variable diagnostic x-ray parameters evaluated were kilovoltage peak (kVp), milliampere-seconds (mAs), and source-to-image distance (SID). The radiation dose was also measured using a dosimeter simultaneously exposed to x-rays perpendicularly incident on the strips. Lastly, the consistency of C–V responses, and any possible degradation after 1–2 months was also analyzed. Each LED strip color was ranked according to its C–V response in each of the investigated parameters. The LED strip color with the best cumulative rank across all the tested parameters was then examined for reproducibility. Our findings revealed that the C–V responses of LED strips are (a) generally low but measurable, (b) inconsistent and fluctuating as a consequence of kVp variations, (c) positively correlated to mAs, (d) negatively correlated to SID, and (e) positively correlated to dose. Overall results suggested cold white LED strip as most feasible for x-ray detection—in comparison to examined colors. Additionally, the reproducibility study using the cold white LED strip found a similar trend of C–V response to all variables except kVp. Outcomes indicate that LED strips have the potential to be exploited for detecting low dose (~0–100 mGy) diagnostic x-rays. However, future studies should be carried out to increase the low C–V signal.

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High-speed non-invasive thermal analysis of high-power light-emitting diode arrays

10.32469/10355/8133 ◽

2010 ◽

Author(s):

Nicholas M. Rada

Keyword(s):

Thermal Analysis ◽

High Power ◽

High Speed ◽

Light Emitting Diode ◽

Light Emitting ◽

Non Invasive

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Synchronization of Chaotic Quantum Dot Light Emitting Diodes under Optical Feedback Effect

10.32792/utq/utjsci/vol7/2/31 ◽

2020 ◽

pp. 144-148

Keyword(s):

Quantum Dot ◽

Delay Time ◽

Chaos Synchronization ◽

Optical Feedback ◽

Light Emitting Diode ◽

Feedback Effect ◽

Complete Synchronization ◽

Light Emitting ◽

Coupling Methods ◽

Coupling Parameters

Chaos synchronization of delayed quantum dot light emitting diode has been studied theortetically which are coupled via the unidirectional and bidirectional. at synchronization of chaotic, The dynamics is identical with delayed optical feedback for those coupling methods. Depending on the coupling parameters and delay time the system exhibits complete synchronization, . Under proper conditions, the receiver quantum dot light emitting diode can be satisfactorily synchronized with the transmitter quantum dot light emitting diode due to the optical feedback effect.

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