X-ray induced luminescence and spatial resolution of phosphor screens

Kandarakis, I.; Cavouras, D.; Panayiotakis, George; Agelis, T; Nomicos, C.; Giakoumakis, G. E.

doi:10.1088/0031-9155/41/2/007

Cited by 36 publications

(25 citation statements)

References 26 publications

(35 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A literature search [12][13][14][15][16] along with a qualitative assessment of several commercially available phosphors suggested the use of gadolinium oxysulphide (Gd 2 O 2 S:Tb), the phosphor used in the construction of the KODAK LANEX Regular screens. A small piece of the actual Kodak Lanex regular screen (7 x 5 mm) with a stated phosphor density of approximately 67 mg/cm 2 was used.…”

Section: Methodsmentioning

confidence: 99%

A CMOS image sensor method of focal spot size measurement

Tuchyna

Paix

2004

Australas. Phys. Eng. Sci. Med.

View full text Add to dashboard Cite

A phosphor opto-coupled monochrome CMOS image sensor with a slit diaphragm was used to investigate focal spot characteristics. Images were captured during x-ray exposure with a triggered frame grabber and subsequently enhanced. Dimensions of the focal spot width (1.39mm) and length (1.92mm) were determined from the focal spot intensity profiles and their corresponding Full Width at Half Maxima (FWHM) in two orthogonal orientations. The CMOS image sensor measurements demonstrated differences in the measured width and length dimensions when compared to film measurements. The obtained nominal focal spot values however showed that image-sensor determined focal spot dimensions agreed with the direct film and film-screen methods when based on the AS/NZS defined nominal focal spot values. The CMOS image sensor tested appears to lack the measurement accuracy required for the measurement of small focal spot sizes due in part to its limited camera sensitivity.

show abstract

Section: Methodsmentioning

confidence: 99%

A CMOS image sensor method of focal spot size measurement

Tuchyna

Paix

2004

Australas. Phys. Eng. Sci. Med.

View full text Add to dashboard Cite

show abstract

“…Grain size affects both emission efficiency and spatial resolution [5,11,16,18]; however, sizes in the range from 5 to 10 mm are generally accepted as a satisfactory compromise between emission efficiency and spatial resolution [5,18]. The phosphors were used in the form of layers (screens) prepared in our laboratory [9,10,19,20,21,22] with various coating weights ranging from approximately 25 to 180 mg/ cm 2 , which are often used in various types of X-ray imaging applications. Preparation was performed by sedimentation of the phosphor powder on fused silica substrates.…”

Section: Methodsmentioning

confidence: 99%

“…Data obtained by the electrometer were converted into light intensity (energy per unit of area and time) using manufacturer's photosensitivity data [9,10,19,20,21,22]. Secondly, the exposure rate X (mR s ±1 ), related to the incident X-ray beam, was determined by a PTW ionization chamber dosimeter (type no.…”

Section: Nep Determinationmentioning

confidence: 99%

See 1 more Smart Citation

Experimental and theoretical assessment of the performance of Gd2O2S:Tb and La2O2S:Tb phosphors and Gd2O2S:Tb–La2O2S:Tb mixtures for X-ray imaging

Kandarakis

Cavouras

2001

Eur Radiol

View full text Add to dashboard Cite

The purpose of this work was to investigate and compare the imaging performance of Gd2O2S:Tb and La2O2S:Tb phosphors as well as of Gd2O2S:Tb and La2O2S:Tb mixtures for use in X-ray imaging detectors (intensifying screens). Phosphors were supplied in powder form and were used to prepare test screens. Three types of screens were prepared: Gd2O2S:Tb; (Gd50La50)O2S:Tb; and La2O2S:Tb. Screens were excited by X-rays with tube voltages from 40 to 120 kV and their efficiency (light intensity or light energy flux over exposure) was measured with a photomultiplier and a dosimeter. The light spectrum was also measured with a monochromator. From these measurements, the number of emitted photons per incident X-ray (NEP) and the zero frequency detective quantum efficiency (DQE(0)) of the screens were determined. Additionally, modulation transfer function (MTF) was measured by the square wave response function (SWRF) method. A theoretical model calculating NEP and DQE was also developed to fit experimental data and predict the performance of Gd2O2S:Tb-La2O2S:Tb mixtures by weight from 10-90% to 90-10%. Gd2O2S:Tb screens exhibited highest NEP, DQE, and MTF at tube voltages higher than 55 kV and lower than 45 kV, whereas La2O2S:Tb screens had better NEP, DQE, and MTF within the 45- to 55-kV range. Maximum NEP values were higher than 700 at 100-120 kV while maximum DQE(0) was 0.314 at 80 kV. Gd2O2S:Tb screens are more efficient for high X-ray tube voltage applications (e.g., abdominal imaging, chest radiography, lumbar spine radiography, CT) and for very low voltage applications (e.g., mammography). La2O2S:Tb screens are useful for medium-range X-ray voltages (e.g., pediatric radiography).

show abstract

“…Its theoretical framework can be used in many fields of application of phosphor screens. Along with modeling of the performance of fluorescent tubes (Grossman, 1998;Narita, 2007), it was successfully adopted for LEDs (Ishida et al, 2008), X-ray and vacuum UV (VUV)-excitation (Baciero et al, 1999;Jeon et al, 2000;Kandarakis et al, 1996), and cathodoluminescence (Narita, 2007). Discussion of other modeling approaches of phosphor powder coatings can be found in Yen et al (2007) and (Kubrin, 2012).…”

Section: Multiple Scattering Of Light In the Powder Screensmentioning

confidence: 99%

Nanophosphor Coatings: Technology and Applications, Opportunities and Challenges

Kubrin

2014

KONA

View full text Add to dashboard Cite

The particle size of conventional commercial phosphor powders used in lighting and displays is in the range from several micrometers to tens of micrometers and it is known that submicrometer-sized phosphors can facilitate a decrease in their consumption and improved resolution of phosphor screens. When the particle size becomes comparable to wavelengths of light, the optical properties of phosphor powders undergo remarkable qualitative changes so that the luminescence performance of nanophosphor screens, along with a very pronounced influence of the particle size, becomes dependent on several additional parameters such as packing density of nanoparticles, refractive index and chemical composition of the medium between them. This brings about both advantages and disadvantages which are discussed in this review of recent literature on the synthesis, deposition, and applications of nanophosphors.

show abstract

X-ray induced luminescence and spatial resolution of phosphor screens

Cited by 36 publications

References 26 publications

A CMOS image sensor method of focal spot size measurement

A CMOS image sensor method of focal spot size measurement

Experimental and theoretical assessment of the performance of Gd2O2S:Tb and La2O2S:Tb phosphors and Gd2O2S:Tb–La2O2S:Tb mixtures for X-ray imaging

Nanophosphor Coatings: Technology and Applications, Opportunities and Challenges

Contact Info

Product

Resources

About