Detection of radiation and positron emission tomography

A method for detection of radiation comprising the steps of:

• entering radiation into a chamber filled with an ionizable and scintillating substance partly for ionizing said ionizable and scintillating substance, partly for converting radiation into light therein;
• detecting at least some of said light temporally, spatially, and spectrally resolved by means of a light detection arrangement;
• avalanche amplifying electrons released as a result of said ionization of said ionizable and scintillating substance, and detecting in two dimensions said avalanche amplified electrons temporally and spatially resolved by means of an electron avalanche detection arrangement;
• correlating detected light and detected avalanche amplified electrons, which are derivable from a single radiation photon;
• and
• producing a signal from said correlated detected light and detected avalanche amplified electrons, wherein said signal produced from said correlated detected light and detected avalanche amplified electrons has spatial and temporal resolutions comparable to the spatial and temporal resolutions of the detected avalanche amplified electrons, and a spectral resolution comparable to the spectral resolution of the detected light.

A positron emission tomography (PET) apparatus for construction of an image of an object containing positron emitting substance, said apparatus comprising:

• a detector arrangement including
• a chamber adapted to be filled with an ionizable substance;
• a radiation entrance arranged such that gamma radiation photon pairs emitted in dependence on said 5 positrons can enter said chamber for ionizing said ionizable and scintillating substance;
• an electron avalanche detection arrangement for avalanche amplification of electrons released as a result of said ionization of said ionizable substance, and for temporally and spatially resolved detection of said electron avalanches;
• a processing means coupled to said detector arrangement, said processing means including
• means for matching a pair of detected electron avalanches, which are derivable from a single radiation photon pair;
• means for producing a signal from said matched electron avalanche pair;
• said means for matching being arranged to repeat the matching for each further detected electron avalanche, and said means for producing being arranged to repeat the producing of a respective signal for each further matched electron avalanche pair;
• and
• reconstruction means for performing a reconstruction process based upon said respective signals as produced by said means for producing, wherein said reconstruction means calculates amounts of emitted positrons from each of an arbitrarily large number of image volumes selected within said object;
• and
• a display unit coupled to said processing means for projecting an image of said amounts of emitted radiation.

A positron emission tomography (PET) method for construction of an image of an object containing positron emitting substance, comprising the steps of:

• entering gamma radiation photon pairs emitted in response to said positrons into a chamber filled with an ionizable substance;
• avalanche amplifying electrons released as a result of said ionization of said ionizable substance and detecting said electron avalanches temporally and spatially resolved by means of an electron avalanche detection arrangement;
• matching a pair of detected electron avalanches, which are derivable from a single radiation photon pair;
• producing a signal from said matched electron avalanche pair;
• repeating the step of matching for each further detected electron avalanche;
• repeating the step of producing a signal for each further matched electron avalanche pair;
• performing a reconstruction process based upon said signals as produced, wherein amounts of emitted positrons from each of an arbitrarily large number of image volumes selected within said object are calculated;
• and
• projecting an image of said amounts of emitted radiation.

A detector arrangement for detection of radiation including a cathode and an anode between which a voltage is applied, said arrangement comprising:

• a chamber arranged at least partially between said cathode and said anode, said chamber being filled with an ionizable and scintillating substance;
• a radiation entrance arranged such that radiation can enter said chamber between and substantially parallel with said cathode and said anode, partly for being converted into light therein, partly for ionizing said ionizable and scintillating substance, whereby electrons released as a result of said ionization of said ionizable and scintillating substance are drifted substantially perpendicular to the direction of said entered radiation by means of said applied voltage;
• a light detection arrangement for temporally and spatially resolved detection of at least some of said light;
• an electron avalanche detection arrangement for avalanche amplification of said drifted electrons, and for temporally and spatially resolved detection of said avalanche amplified electrons, said electron avalanche detection arrangement being oriented such that said drifted electrons are accelerated, during avalanche amplification, in a direction substantially perpendicular to the direction of said entered radiation;
• correlating means for correlating detected light and detected avalanche amplified electrons, which are derivable from a single radiation photon;
• and
• producing means for producing a single signal from said correlated detected light and detected avalanche amplified electrons.

A method for detection of radiation comprising the steps of:

• entering radiation into a chamber filled with an ionizable and scintillating substance partly for ionizing said ionizable and scintillating substance, partly for converting radiation into light therein;
• detecting at least some of said light temporally and spatially resolved by means of a light detection arrangement;
• drifting electrons released as a result of said ionization of said ionizable and scintillating substance in a direction substantially perpendicular to the direction of said entered radiation by means of applying an electrical field within said chamber;
• avalanche amplifying drifted electrons through acceleration of said drifted electrons in a direction substantially perpendicular to the direction of said entered radiation by means of applying an electrical field within said chamber;
• detecting said avalanche simplified electrons temporally and spatially resolved by means of an electron avalanche detection arrangement;
• correlating detected light and detected avalanche amplified electrons, which are derivable from a single radiation photon;
• and
• producing a signal from said correlated detected light and detected avalanche amplified electrons.