Method and apparatus for real-time radiation imaging

Claim 1

A method for producing a real-time electronic signal representing a radiation image of a body being examined, comprising: directing a beam of ionizing radiation at the body and toward a luminescent phosphor screen positioned behind the body; the ionizing radiation causing migration of electrons within the phosphor screen which results in ionization of the phosphor screen; the degree of ionization of the phosphor screen being variable over the screen and dependent upon the amount of ionizing radiation which passes through or around the body and impinges upon a particular point of the screen; scanning the phosphor screen with a laser beam having a wavelength approximately equal to the stimulation wavelength of the phosphor screen; the laser beam having a photon flux density sufficiently intense to rapidly stimulate the phosphor screen and cause very rapid and nearly complete detrapping of the electrons which migrated during ionization of the phosphor screen; the laser beam scanning across particular points of the phosphor screen so as to provide stimulation of the particular points for time periods of between 50 to 200 nanoseconds; measuring the luminescent emissions which result from striking the phosphor screen with the laser beam; converting the measurements of the luminescent emissions and their associated locations into an electronic signal which is representative of the radiation image impinging upon the phosphor screen; and synchronizing the luminescent emission measurements for particular points of the screen with the location of the particular points upon the screen.

Claim 2

A method for producing a real-time electronic signal representing a radiation image of a body being examined, comprising: directing a beam of ionizing radiation at the body and toward a luminescent phosphor screen positioned behind the body; the ionizing radiation causing migration of electrons within the phosphor screen which results in ionization of the phosphor screen; the degree of ionization of the phosphor screen being variable over the screen and dependent upon the amount of ionizing radiation which passes through or around the body and impinges upon a particular point of the screen; scanning the phosphor screen with a laser beam having a wavelength approximately equal to the stimulation wavelength of the phosphor screen; the laser beam having a photon flux density sufficiently intense to rapidly stimulate the phosphor screen and cause very rapid and nearly complete detrapping of the electrons which migrated during ionization of the phosphor screen; the laser beam scanning across particular points of the phosphor screen so as to provide stimulation of the particular points for time periods of between 50 to 200 nanoseconds; measuring the luminescent emissions which result from striking the phosphor screen with the laser beam; converting the measurements of the luminescent emissions and their associated locations into an electronic signal which is representative of the radiation image impinging upon the phosphor screen; and synchronizing the luminescent emission measurements for particular points of the screen with the location of the particular points upon the screen.

Claim 14

A method for producing a real-time radiation image of a body being examined, comprising: directing a beam of ionizing radiation through the body and at a luminescent phosphor screen to cause migration of electrons within the phosphor of the screen which results in ionization of the phosphor; the degree of ionization of the phosphor screen being variable over the screen and dependent upon the amount of ionizing radiation which passes through or around the body and impinges upon a particular locational point upon the screen; striking the phosphor screen with a laser beam to stimulate phosphor screen; the laser beam having a wavelength approximately equal to the stimulation wavelength of the phosphor of the screen; the laser beam also having a photon flux density sufficiently intense to cause very rapid and nearly complete detrapping of the electrons which migrated during ionization of the phosphor screen; particular locational points of the phosphor screen being struck by the laser beam for time periods of between approximately 50 to 1000 nanoseconds; measuring the luminescent emissions which result from striking the phosphor screen with the laser beam in a manner which allows the measurements of luminescent emissions from particular points on the phosphor screen to be associated with the location of that point on the phosphor screen; converting the measurements from above into an electronic signal indicating both the value and location of the emission measurements; and using an electronic video display to transform the electronic signal into a visually perceivable image which represents the radiation image which passes through and around the body and strikes the phosphor screen.

Claim 15

A method for producing a real-time radiation image of a body being examined, comprising: directing a beam of ionizing radiation through the body and at a luminescent phosphor screen to cause migration of electrons within the phosphor of the screen which results in ionization of the phosphor; the degree of ionization of the phosphor screen being variable over the screen and dependent upon the amount of ionizing radiation which passes through or around the body and impinges upon a particular locational point upon the screen; striking the phosphor screen with a laser beam to stimulate phosphor screen; the laser beam having a wavelength approximately equal to the stimulation wavelength of the phosphor of the screen; the laser beam also having a photon flux density sufficiently intense to cause very rapid and nearly complete detrapping of the electrons which migrated during ionization of the phosphor screen; particular locational points of the phosphor screen being struck by the laser beam for time periods of between approximately 50 to 1000 nanoseconds; measuring the luminescent emissions which result from striking the phosphor screen with the laser beam in a manner which allows the measurements of luminescent emissions from particular points on the phosphor screen to be associated with the location of that point on the phosphor screen; converting the measurements from above into an electronic signal indicating both the value and location of the emission measurements; and using an electronic video display to transform the electronic signal into a visually perceivable image which represents the radiation image which passes through and around the body and strikes the phosphor screen.

Claim 19

An apparatus for transforming a radiation image into a real-time electronic signal which can be recorded or viewed substantially simultaneously in time with the radiation image, comprising: a source of ionizing radiation; a luminescent phosphor screen positioned to receive ionizing radiation from the source of ionizing radiation; the phosphor screen and source of ionizing radiation being spaced sufficiently far apart so that a body being examined can be interpositioned therebetween; ionizing radiation from said source passing through and around the interpositioned body creating a radiation image thereof which strikes the phosphor screen; a scanning laser beam for stimulating the phosphor screen to provide luminescent emissions at a plurality of locational points across the screen; the laser beam having a photon flux density sufficiently intense to cause very rapid and nearly complete detrapping of electrons which have migrated during ionization of the phosphor screen; the laser beam stimulating particular locational points of the phosphor screen for time periods of between approximately 50 to 1000 nanoseconds to provide for nearly complete detrapping; an emission detector for measuring the emissions from the plurality of locational points and providing an electronic signal thereof; means for synchronizing the location of the stimulated point on the phosphor screen with the corresponding electronic signal of the emission from that point; thereby providing an electronic signal which can substantially simultaneously produce a visual representation of the radiation image or which can be recorded for future reference.

Claim 20

An apparatus for transforming a radiation image into a real-time electronic signal which can be recorded or viewed substantially simultaneously in time with the radiation image, comprising: a source of ionizing radiation; a luminescent phosphor screen positioned to receive ionizing radiation from the source of ionizing radiation; the phosphor screen and source of ionizing radiation being spaced sufficiently far apart so that a body being examined can be interpositioned therebetween; ionizing radiation from said source passing through and around the interpositioned body creating a radiation image thereof which strikes the phosphor screen; a scanning laser beam for stimulating the phosphor screen to provide luminescent emissions at a plurality of locational points across the screen; the laser beam having a photon flux density sufficiently intense to cause very rapid and nearly complete detrapping of electrons which have migrated during ionization of the phosphor screen; the laser beam stimulating particular locational points of the phosphor screen for time periods of between approximately 50 to 1000 nanoseconds to provide for nearly complete detrapping; an emission detector for measuring the emissions from the plurality of locational points and providing an electronic signal thereof; means for synchronizing the location of the stimulated point on the phosphor screen with the corresponding electronic signal of the emission from that point; thereby providing an electronic signal which can substantially simultaneously produce a visual representation of the radiation image or which can be recorded for future reference.