System for reading out a plurality of differing storage phosphor screens
View Patent ↗A system has been described for reading out a plurality of stimulable phosphor screens, plates or panels, after exposing said screens to X-rays having an energy in the range from 25 up to 150 kVp, the screens being selected from the group consisting of binder containing powder screens and binderless, crystalline or amorphous phosphor layer screens; wherein said phosphors are divalent europium activated alkali halide type phosphors wherein said halide is at least one of bromide or a combination of bromide with at least one of chloride and iodide, or divalent europium activated alkaline earth metal halide phosphors, wherein said halide is at least one of fluoride, chloride, bromide and iodide or a combination thereof, and wherein said screens are consecutively subjected to following steps of stimulating said phosphor screens by means of stimulation energy; detecting stimulated emission energy, emitted by the phosphor screen upon stimulation; converting detected energy into a signal representation of said radiation image; erasing said phosphor screen by exposing it to erasing energy; wherein differences in maximum wavelength of stimulation spectra of said differing screens are in the range from 10 nm up to 100 nm, wherein differences in maximum wavelength of stimulated emission spectra of said differing screens are in the range from 10 nm up to 150 nm, and wherein filtering means are provided for preventing stimulation radiation from being detected by detecting means, and for transmitting radiation emitted upon stimulation.
1. A system for reading out a plurality of differing stimulable phosphor screens, plates or panels, after exposing said screens to X-rays having an energy in the range from 25 up to 150 kVp, the phosphors of which are coated on a substrate in a phosphor layer selected from the group consisting of binder containing powder screens and binderless, crystalline phosphor layer screens; wherein said screens are consecutively subjected to following steps:
1) Stimulating said screens with stimulation light,
2) detecting stimulated emission light, emitted by the phosphor screen upon stimulation;
3) converting detected light signal into a digital representation of said radiation image;
4) erasing said phosphor screen by exposing it to erasing energy;
whereby the differences in the position of the maxima in the stimulation spectra of said differing screens are in the range from 10 nm up to 100 nm, whereby the differences in position of the maxima in the stimulated emission spectra of said differing screens are in the range from 10 nm up to 150 nm, and wherein filtering means are provided for preventing stimulation radiation from being detected by detecting means, and for transmitting radiation emitted upon stimulation.
2. A system according to claim 1 , wherein said phosphors are divalent europium activated CsX type phosphors, wherein said X represents Br or a combination of Br with at least one of Cl and I.
3. A system according to claim 2 , wherein said binder medium layer of ground needle-shaped CsBr:Eu-type phosphor in non-aligned powdery form.
4. A system according to claim 2 , wherein said crystalline layer comprises said phosphor in a homogeneously solidified form.
5. A system according to claim 1 , wherein said phosphors are (Ba,M II )FX′:Eu type phosphors, wherein M II is an alkaline earth metal and wherein X′ is Cl, Br and/or I.
6. A system according to claim 5 , wherein M II is Sr 2+ .
7. A system according to claim 1 , wherein both divalent europium activated CsX type phosphors, wherein said X represents Br or a combination of Br with at least one of Cl and I phosphors and (Ba,M II )FX′:Eu type phosphors, wherein M II is an alkaline earth metal and wherein X′ is Cl, Br and/or I are used.
8. A system according to claim 7 , wherein said binder medium layer of ground needle-shaped CsEr:Eu-type phosphor in non-aligned powdery form.
9. A system according to claim 7 , wherein said crystalline layer comprises said phosphor in a homogeneously solidified form.
10. A system according to claim 1 wherein said filtering means comprises a dye, transmitting light in the wavelength range from 350 nm up to 500 nm.
11. A system according to claim 10 , wherein said binder medium layer of ground needle-shaped CsBr:Eu-type phosphor in non-aligned powdery form.
12. A system according to claim 10 , wherein said crystalline layer comprises said phosphor in a homogeneously solidified form.
13. A system according to claim 1 , wherein said binderless phosphor layer screens are provided with needle-shaped phosphors, having phosphor needles, aligned in parallel, under an angle in a range between 60° and 90° verus said substrate.
14. A system according to claim 1 , wherein said binder medium layer of ground needle-shaped CsBr:Eu-type phosphor in non-aligned powdery form.
15. A system according to claim 1 , wherein said crystalline layer comprises said phosphor in a homogeneously solidified form.
16. A system according to claim 1 , wherein converting detected energy into a signal representation of said radiation image, proceeds via an array of transducer element.