Interstitial X-ray needle

Abstract

An interstitial X-ray needle includes an elongated X-ray tube coupled to an electron emitter at one end of the tube, with a converter element being disposed at a tip of the other end of the tube for converting emitted electrons into X-ray; a solenoid coil wound around the tube for providing a magnetic field that confines the emitted electrons within a narrow beam; an elongated outer casing enclosing the tube and coil; and a pipe coaxially disposed between the casing and the tube for defining an inner annular flow chamber between the tip of the tube and a coolant inlet in the casing and an outer annular flow chamber between the tip of the tube and a coolant outlet in the casing.

What is claimed is: 
     
       1. An interstitial X-ray needle, comprising an elongated X-ray tube coupled to an electron emitter at one end of the tube, with a converter element being disposed at a tip of the other end of the tube for converting emitted electrons into X-rays:   a solenoid coil wound around the tube for providing a magnetic field that confines the emitted electrons within a narrow beam;   an elongated outer casing enclosing the tube and coil; and   means within the casing defining coolant flow chambers for directing coolant to and from the tip of the tube.   
     
     
       2. A needle according to claim 1, wherein the flow-chamber-defining means comprises a pipe coaxially disposed between the casing and the tube for defining an inner annular flow chamber between the tip of the tube and a first opening in the casing and an outer annular flow chamber between the tip of the tube and a second opening in the casing. 
     
     
       3. A needle according to claim 1, wherein the flow-chamber-defining means comprises a plurality of pipes disposed between the casing and the tube wherein each pipe defines an input flow chamber between the tip of the tube and at least one inlet opening in the casing and wherein the space between the tube and the casing not occupied by the pipes defines an output flow chamber between the tip of the tube and an outlet opening in the casing. 
     
     
       4. An interstitial X-ray needle, comprising an elongated X-ray tube coupled to an electron emitter at one end of the tube, with a converter element being disposed at a tip of the other end of the tube for converting emitted electrons into X-rays;   a solenoid coil wound around the tube for providing a magnetic field that confines the emitted electronss within a narrow beam;   an elongated outer casing enclosing the tube and coil; wherein a portion of the casing extending at least approximately five centimeters from the tip of the tube has a maximum outside diameter of approximately two millimeters; and   means within the casing defining coolant flow chambers for directing coolant to an from the tip of the tube.   
     
     
       5. A needle according to claim 4, wherein the flow-chamber-defining means comprises a pipe coaxially disposed between the casing and the tube for defining an inner flow chamber between the tip of the tube and a first opening in the casing and an outer annular flow chamber between the tip of the tube and a second opening in the casing. 
     
     
       6. A needle according to claim 4, wherein the flow-chamber-defining means comprises a plurality of pipes disposed between the casing and the tube wherein each pipe defines an input flow chamber between the tip of the tube and at least one inlet opening in the casing and wherein the space between the tube and the casing not occupied by the pipes defines an output flow chamber between the tip of the tube and an outlet opening in the casing. .Iadd. 
     
     
       7.  An interstitial X-ray needle, including, first means for producing a plurality of electrons,   second means for including a tube for directing the electrons from the first means in a particular path,   third means disposed at the end of the particular path for converting the electrons to X-rays,   fourth means including a casing disposed in enveloping relationship to the tube for cooling the third means, and   fifth means disposed on the tube for confining the electrons to a beam during the direction of the electrons in the particular path to the third means. .Iaddend..Iadd.8. An interstitial X-ray needle as set forth in claim 7 wherein   the third means receives the electrons after the passage of the electrons in the particular path through the tube and converts the electrons to   
     
     
        X-rays. .Iaddend..Iadd.9.  An interstitial X-ray needle as set forth in claim 8 wherein the tube has a tip and the third means includes a converter element disposed at the tip of the tube to receive the electrons after the passage of the electrons through the first tube and to convert the received electrons to X-rays. .Iaddend..Iadd.10. An interstitial X-ray needle as set forth in claim 9 wherein   the tube and the casing are disposed in a coaxial relationship.   
     
     
        .Iaddend..Iadd.11.  An interstitial X-ray needle as set forth in claim 7 wherein the casing envelopes the second means, the third means and the fifth means and provides for a flow of a cooling fluid past the third means to cool   
     
     
        the third means. .Iaddend..Iadd.12.  An interstitial X-ray needle as set forth in claim 7, including, there being a space between the tube and the casing,   there being at least one hollow pipe in the space between the tube and the casing, the hollow pipe being included in the fourth means for introducing fluid to the third means to cool the third means,   the hollow pipe only partially occupying the space between the tube and the casing, and   the remaining space between the tube and the casing providing for the flow   
     
     
        of the cooling fluid from the third means. .Iaddend..Iadd.13.  An interstitial X-ray tube as set forth in claim 7 wherein the fifth means is operative to confine the electron beam to a diameter no greater than approximately four tenths of a millimeter (0.4 mm). .Iaddend..Iadd.14. An interstitial X-ray tube as set forth in claim 7 wherein   the casing has a width no greater than approximately 2.8 millimeters.   
     
     
        .Iaddend..Iadd.15.  An interstitial X-ray needle, including: first means for producing a plurality of electrons,   a tube disposed to receive the electrons from the first means and to pass the electrons through the tube,   second means disposed at the end of the tube for receiving the electrons after the passage of the electrons through the tube and for converting the received electrons to X-rays,   a casing disposed in enveloping relationship to the tube, there being a space between the tube and that casing,   third means for passing a cooling fluid through the space between the tube and the casing and past the second means to cool the second means, and   fourth means disposed in the space between the tube and the casing for confining the electrons to a beam during the passage of the electrons   
     
     
        through the first tube to the second means. .Iaddend..Iadd.16.  An interstitial X-ray needle as set forth in claim 15, including, a housing enveloping the tube and the casing and the first means. .Iaddend..Iadd.17. An interstitial X-ray tube as set forth in claim 16 wherein the casing has a diameter no greater than approximately 2.8 millimeters. .Iaddend..Iadd.18. An interstitial X-ray tube as set forth in claim 15 wherein   the tube has a tip and the second means includes a converter element disposed at the tip of the tube to receive the electrons after the passage of the electrons through the tube and to convert the received electrons to   
     
     
        X-rays. .Iaddend..Iadd.19.  An interstitial X-ray tube as set forth in claim 15, including, at least one hollow pipe partially occupying the space between the tube and the casing to provide for the passage of the cooling fluid through the hollow pipe to the second means and to provide for the passage of the cooling fluid from the second means through the remaining space between the tube and the casing,   the hollow pipe being included in the third means. .Iaddend..Iadd.20. An interstitial X-ray tube as set forth in claim 15 wherein   the fourth means is operative to confine the electron beam to a diameter no greater than approximately four tenths of a millimeter (0.4 mm).   
     
     
        .Iaddend..Iadd.21.  An interstitial X-ray needle, including: first means for producing a plurality of electrons,   a tube disposed to receive the electrons from the first means and to pass the electrons through the tube,   second means for receiving the electrons after the passage of the electrons through the tube and for converting the electrons to X-rays,   a casing disposed in spaced relationship to the tube,   third means for passing a cooling fluid through the space between the tube and the casing and past the second means to cool the second means, and   magnetic means disposed on the tube in the space between the tube and the casing for confining the electrons to a beam during the flow of the electrons through the tube. .Iaddend.