Gamma camera system

• US 4,061,919 A
• Filed: 07/06/1976
• Issued: 12/06/1977
• Est. Priority Date: 07/06/1976
• Status: Expired due to Term

• Current Assignee: Ohio State University
• Original Assignee: Ohio State University
• Inventors: Miller, Don W., Gerber, Mark S.
• Primary Examiner(s): Dixon, Harold A.
• Application Number:
  US05/702,981
• Time in Patent Office: 518 Days
• Field of Search: 250/363 S, 250/369, 250/370
• US Class Current: 250/363.02
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/1642 using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras
• CPC Class Codes: G01T 1/2928 using solid state detectors

Abstract

A gamma camera system having control components operating in conjunction with a solid state detector. The detector is formed of a plurality of discrete components which are associated in geometrical or coordinate arrangement defining a detector matrix to derive coordinate signal outputs. These outputs are selectively filtered and summed to form coordinate channel signals and corresponding energy channel signals. A control feature of the invention regulates the noted summing and filtering performance to derive data acceptance signals which are addressed to further treating components. The latter components include coordinate and energy channel multiplexers as well as energy-responsive selective networks. A sequential control is provided for regulating the signal processing functions, of the system to derive an overall imaging cycle.

Claims

1. In a system for imaging the distribution within a region of interest of isotopic materials emitting radiation of given photon energy, said system including composite solid state detector means having a plurality of discrete components which are operationally associated to provide spatial coordinate parameter outputs representative of the spatial disposition of corresponding interactions of said radiation with said detector means, the improvement comprising:

first output treating means connected to receive said spatial coordinate parameter outputs of said detector means components, actuable to selectively filter and sum said outputs to derive corresponding coordinate channel signals and an energy channel signal having values corresponding respectively with said spatial disposition and given photon energy exhibited at a said interaction, said first output treating means further including control means for effecting said actuation to filter and sum and for deriving a data acceptance signal in correspondence with said coordinate and energy channel signals, said control means being responsive to a received reset signal to reset said first output means to a clear condition;

means including spatial coordinate multiplexer means and energy channel multiplexer means respectively coupled to be addressed by said energy channel signals, each said multiplexer means being responsive to a coded actuating signal to effect a transference of said channel signals addressed thereto;

process control means including memory means for receiving said data acceptance signals and selectively retaining them in received serialized fashion, and actuable to derive said coded actuating signal in correspondence with said serialized data acceptance signals;

sequential control means for selectively actuating said process control means and regulating an operational cycle of said system; and

second treating means responsive to said transferred channel signals for deriving readout information representative thereof.

2. The improved system of claim 1 including;

storage means, having receive and hold modes, for receiving, when transferred, each said coordinate and energy channel signal when in said receive mode, and actuable to assume said hold mode retaining each said channel signal over a given interval, said storage means having outputs for asserting each said retained channel signal; and

wherein said sequential control means is configured for selectively actuating said storage means to derive and retain said hold mode for said given interval.

3. The improved system of claim 2 in which said sequential control means is configured for deriving and submitting said reset signal to said control means in correspondence with said storage means actuation.

4. In a system for imaging the distribution within a region of interest of isotopic materials emitting radiation exhibiting two or more levels of photon energy, said system including composite solid state detector means having a plurality of discrete components which are operationally associated to provide spatial coordinate parameter outputs representative of the spatial disposition of corresponding interactions of said radiation with said detector means, the improvement comprising:

first output treating means connected to receive said spatial coordinate parameter outputs of said detector means components, actuable to selectively filter and sum said outputs to derive corresponding coordinate channel signals and an energy channel signal having values corresponding respectively with said spatial disposition and the level of said photon energy exhibited at a said interaction, and including control means for effecting said actuation to filter and sum and for deriving a data acceptance signal in correspondence with said coordinate and energy channel signals, said control means being responsive to a reset said first output means to a clear condition;

means including spatial coordinate multiplexer means and energy channel multiplexer means respectively coupled to be addressed by said coordinate channel and said energy channel signals, each said multiplexer means being responsive to a coded actuating signal to effect a transference of said channel signals addressed thereto;

process control means including means for receiving said data acceptance signals to effect a de-randomization thereof and actuable to provide a said coded actuating signal in correspondence with a said data acceptance signal;

second treating means including divider network means responsive to a said energy channel multiplexer means transferred energy channel signal and to said spatial coordinate multiplexer means transferred signals for normalizing said spatial coordinate channel signals with respect to the said photon energy related value of their corresponding said energy channel signal, said second treating means being configured for deriving readout information corresponding with said normalized spatial coordinate channel signals; and

sequential control means for selectively actuating said process control means and regulating an operational cycle of said system.

5. The improved system of claim 4 wherein said divider network is configured to carry out said normalization by effecting a division of the value of each said spatial coordinate channel signal by the value of said energy channel signal.

6. The improved system of claim 5 wherein said second treating means include means for evaluating the peak value of each said energy channel signal with respect to predetermined upper and lower limit values selected in correspondence with each said level of photon energy exhibited by said isotopic materials.

7. In a system for imaging the distribution within a region of interest of isotopic materials emitting radiation of given photon energy or energies, said system including composite solid state detector means having a plurality of discrete components which are operationally associated within predetermined portions of said detector means to provide spatial coordinate parameter, x-, y- designated outputs representative of the spatial disposition of corresponding interactions of said radiation with said detector means, the improvement comprising:

first output treating means connected to receive said spatial coordinate parameter, x-, y- designated outputs of said components of each said predetermined portion of said detector means, actuable to selectively filter and sum said outputs when operating from a clear condition to derive corresponding x- and y- designated coordinate channel signals and an energy channel signal having values corresponding respectively with said spatial disposition and given energy exhibited at a said interaction, said first output treating means including first evaluating means responsive to the value of said given energy equaling or exceeding a predetermined value to derive a select output, and further including control means responsive to the presence of said evaluating means select output for effecting said actuation to filter and sum and for deriving a data acceptance signal in time correspondence with said coordinate channel and energy channel signals, said control means being responsive to a reset signal when submitted thereto to reset said first output treating means to said clear condition;

means including x-position multiplexer means, y-position multiplexer means and energy multiplexer means respectively coupled to be addressed by said x- and y- designated coordinate and energy channel signals, each said multiplexer means being responsive to a coded actuating signal to transfer said channel signals addressed thereto;

storage means, having receive and hold modes, for receiving each transferred said channel signal then in said receive mode, and actuable to assume said hold mode retaining each said channel signal over a given interval, said storage means having outputs for asserting each said retained channel signal;

process control means including asynchronous memory means for accepting and retaining said data acceptance signals in received serialized fashion and actuable to provide said coded actuating signal;

sequential control means for selectively actuating said process control means to effect selective transfer of said channel signals to said storage means, and for actuating said storage means to derive and retain said hold mode for said given interval; and

second treating means responsive to said channel signals asserted at said storage means outputs for deriving readout information representative thereof.

8. The improved system of claim 7 in which said process control means asynchronous memory means is configured and arranged for de-randomizing the receipt of said data acceptance signals to effect said serialization in a time domain independent of the rate of said receipt.

9. The improved system of claim 7 in which said sequential control means is configured and arranged for generating and submitting a said reset signal subsequent to said actuation of said storage means to assume said hold mode.

10. The improved system of claim 7 wherein:

said second treatment means includes second evaluating means for evaluating the peak value of each said energy channel signal over a given interval of time, and having a select output when said energy channel signal peak value lies within predetermined limits; and

said sequential control means is configured and arranged for generating said reset signal in the absense of said second evaluating means select output.

11. The improved system of claim 10 in which said sequential control means is configured and arranged for generating said reset signal in the absence of said second evaluating means select output and at the termination of said second evaluating means given interval of time.

12. The improved system of claim 7 in which said first output treating means includes peak detector means configured and arranged for receiving and retaining the peak value of a said summed, filtered x-, y- designated output deriving said energy channel signal at least until said storage means actuation.

13. The improved system of claim 7 in which said second treatment means includes divider network means responsive to the said x- and y- designated coordinate channel signals for normalizing said signals with respect to the photon energy of their derivative said interaction.

14. The improved system of claim 7 in which said second treatment means includes:

first divider network means coupled to receive said x- designated coordinate channel signal asserted at a said storage means output; and

second divider network means coupled to receive said y-designated coordinate channel signal asserted at a storage means output;

said first and second divider networks being configured and arranged in operative association with the said energy channel signal output asserted at a said storage means output to effect a division of the values of said coordinate channel signals by the value of the corresponding said energy channel to provide x- and y- designated spatial signals normalized with respect to the said energy channel signal value;

said second treatment means deriving said readout information from said normalized x- and y- designated spatial signals.

15. The improved system of claim 7 in which:

said process control means is configured and arranged for de-randomizing the receipt of said data acceptance signal to effect said serialization in a time domain independent of the rate of said receipt; and

wherein said sequential control means is configured and arranged for generating and submitting a said reset signal subsequent to said actuation of said storage means to assume said hold mode.

16. The improved system of claim 7 in which:

said second treatment means includes second evaluating means for evaluating the peak value of each said energy channel signal over a select interval of time, and having a select output when said energy channel signal peak value lies within predetermined limits; and

said sequential control means is configured and arranged for said actuation of said storage means to derive a said hold mode given interval substantially in correspondence with said second evaluating means select interval, and the generating said reset signal in the absence of said second evaluating means select output.

17. The improved system of claim 16 in which said first output treating control means is configured and arranged to reset said first output treating means to said clear condition in the absence of said first evaluating means select output.

18. The improved system of claim 17 in which said sequential control means is configured and arranged for generating and submitting a said reset signal subsequent to said actuation of said storage means to assume said hold mode.

19. The improved system of claim 18 in which said first output treating means includes peak detector means configured and arranged for receiving and retaining the peak value of a said summed, filtered x-, y- designated output deriving said energy channel signal at least until said storage means actuation.

20. The improved system of claim 19 in which said second treatment means includes divider network means responsive to the said x- and y- designated coordinate channel signals for normalizing said signals with respect to the photon energy of their derivative and interaction.

21. The improved system of claim 19 in which said second treatment means includes:

first divider network means coupled to receive said x- designated coordinate channel signal asserted at a said storage means output; and

second divider network means coupled to receive said y- designated coordinate channel signal asserted at a said storage means output;

said first and second divider networks being configured and arranged in operative association with the said energy channel signal output asserted at a said storage means output to effect a division of the values of said coordinate channel signals by the value of the corresponding said energy channel signal to provide x- and y- designated spatial signals normalized with respect to the said energy channel signal value;

said second treatment means deriving said readout information from said normalized x- and y- designated spatial signals.

22. The improved system of claim 21 in which said process control means asynchronous memory means is configured and arranged for de-randomizing the receipt of said data acceptance signals to effect said serialization in a time domain independent of the rate of said receipt.

23. In a system for imaging the distribution within a region of interest of isotopic material emitting radiation of given photon energy, said system including composite solid state detector means having a plurality of mutually adjacently disposed discrete detector components each having one of two oppositely disposed charge collecting surfaces positioned substantially within a common plane for exposure to said radiation, said components being arranged to establish linearly oriented groupings of respective said opposed surfaces, each said grouping of surfaces being electrically intercoupled and associated with impedance means for providing x- and y- designated coordinate outputs from respective mutually orthogonally aligned and oppositely disposed ones of said groupings associated with a common said detector component at which an interaction with said radiation corresponding with said coordinate output occurs, the improvement comprising:

x- coordinate output treating means responsive to said x- designated coordinate outputs, actuable to selectively filter and sum said outputs from a clear condition to derive corresponding x- designated coordinate channel signals and an energy signal having values corresponding respectively with a coordinate aspect of the spatial location of said interaction and the value of said photon energy thereof, and including control means for effecting said actuation to filter and sum and for deriving an x- data signal corresponding with said channel and energy signals, said control means being responsive to a reset signal when submitted thereto to reset said treating means to said clear condition;

y- coordinate output treating means responsive to said y- designated coordinate outputs, actuable to selectively filter and sum said outputs from a clear condition to derive corresponding y- designated coordinate channel signals and an energy signal having values corresponding respectively with a coordinate aspect of the spatial location of said interaction and the value of said photon energy thereof, and including control means for effecting said actuation to filter and sum and for deriving a y- data signal corresponding with said channel and energy signals, said control means being responsive to a reset signal when submitted thereto to reset said treating means to said clear condition;

means including x- position multiplexer means, y- position multiplexer means and energy multiplexer means, respectively coupled to be addressed by said x- and y- designated coordinate channel signals and at least one said energy signal, each said multiplexer means being responsive to a coded actuating signal to transfer said signals addressed thereto;

process control means including coincidence network means responsive the said x- data and y- data signals corresponding with a given said interaction for deriving a pair code signal, and asynchronous memory means responsive to said pair code signal for accepting and retaining said x- and y- data signals in received serialized fashion and actuable to provide and assert said coded actuating signal at said multiplexer means;

means responsive to said x- and y- designated coordinate channel signals when transferred from said x- position multiplexer means, said y- position multiplex means, and energy multiplexer means for deriving readout information representative thereof; and

sequential control means for selectively actuating said process control means to effect said transfer of said signals.

24. The improved system of claim 23 including:

storage means, having receive and hold modes, for receiving, when transferred, each said channel and energy signal when in said receive mode, and actuable to assume said hold mode retaining each said channel signal over a given interval, said storage means having outputs for asserting each said retained channel signal; and

wherein said sequential control means is configured and arranged for selectively actuating said storage means to derive and retain said hold mode for said given interval.

25. The improved system of claim 23 in which each said x- coordinate output treating means and said y- coordinate output treating means include first evaluating means responsive to the value of said energy signal equaling or exceeding a predetermined value to derive a select output;

and said control means is responsive to the presence of said select output for effecting said actuation to filter and sum.

26. The improved system of claim 23 in which:

each said x- coordinate output treating means and said y- coordinate output treating means include a summing network for deriving said energy signal, said summing network including a stage deriving a derivative signal representing the time derivative of said energy values of said coordinate output signals; and

the said control means of each said output treating means is responsive to said derivative signal for deriving a designated said x- data or y- data signal.

27. The improved system of claim 26 in which:

each said x- coordinate output treating means and said y- coordinate output treating means includes comparator means responsive to the value of said summing network stage derivative signal equaling or exceeding a predetermined reference value for deriving a given output; and

each said control means of a said output treating means is responsive to said given output to effect said actuation and derive a designated said x- data or y- data signal.

28. The improved system of claim 23 in which said process control means asynchronous memory means is configured and arranged for de-randomizing the receipt of said x- and y- data signals to effect said serialization in a time domain independent of the rate of said receipt.

29. The improved system of claim 23 in which said sequential control means is configured and arranged for deriving and submitting said reset signal to said control means subsequent to said actuation of said process control means.

30. The improved system of claim 29 including:

storage means, having receive and hold modes, for receiving, when transferred, each said channel and energy signal when in said receive mode, and actuable to assume said hold mode retaining each said channel signal over a given interval, said storage means having outputs for asserting each said retained channel signal; and

wherein said sequential control means is configured and arranged for selectively actuating said storage means to derive and retain said hold mode for said given interval.

31. The improved system of claim 30 in which each said x- coordinate output treating means and said y- coordinate output treating means include first evaluating means responsive to the value of said energy signal equaling or exceeding a predetermined value to derive a select output;

and said control means is responsive to the presence of said select output for effecting said actuation to filter and sum.

32. The improved system of claim 31 in which:

each said x- coordinate output treating means and said y- coordinate output treating means include a summing network for deriving said energy signal, said summing network including a stage deriving a derivative signal representing the time derivative of said energy values of said coordinate output signals; and

the said control means of each side output treating means is responsive to said derivative signal for deriving a designated said x- data or y- data signal.

33. The improved system of claim 31 in which:

each said x- coordinate output treating means and said y- coordinate output treating means include a summing network for deriving said energy signal, said summing network including a stage deriving a derivative signal representing the time derivative of said energy value of said coordinate output signals; and

the said control means of each said output treating means is responsive to said derivative signal for deriving a designated said x- data or y- data signal.

34. The improved system of claim 33 in which:

each said x- coordinate output treating means and said y- coordinate output treating means includes comparator means responsive to the value of said summing network stage derivative signal equaling or exceeding a predetermined reference value for deriving a given output; and

each said control means of a said output treating means is responsive to said given output to effect said actuation and derive a designated said x- data or y- data signal.

35. The improved system of claim 23 including:

storage means, having receive and hold modes, for receiving, when transferred, each said channel and energy signal when in said receive mode, and actuable to assume said hold mode retaining each said channel signal over a given interval, said storage means having outputs for asserting each said retained channel signal;

wherein said sequential control means is configured and arranged for selectively actuating said storage means to derive and retain said hold mode for said given interval; and

wherein each said x- coordinate output treating means and said y- coordinate output treating means include first evaluating means responsive to the value of said energy signal equaling or exceeding a predetermined value to derive a select output; and

said control means is responsive to the presence of said select output for effecting said actuation to filter and sum.

36. The improved system of claim 35 in which:

each said x- coordinate output treating means and said y- coordinate output treating means include a summing network for deriving said energy signal, said summing network including a stage deriving a derivative signal representing the time derivative of said energy values of said coordinate output signals; and

the said control means of each said output treating means is responsive to said derivative signal for deriving a designated and x- data or y- data signal.

37. The improved system of claim 36 in which said sequential control means is configured and arranged for generating and submitting a said reset signal subsequent to said actuation of said storage means to assume said hold mode.

38. The improved system of claim 36 wherein:

said means for deriving said readout information includes second evaluating means for evaluating the peak value of each said energy signal over a given interval of time, and having a select output then said energy signal peak lies within predetermined limits; and

said sequential control means is configured and arranged for generating and submitting a reset signal in the absence of said second evaluating means select output.

39. The improved system of claim 38 in which said sequential control means is configured and arranged for generating said reset signal in the absence of said second evaluating means select output and at the termination of said second evaluating means given interval time.

40. The improved system of claim 36 in which said means for deriving readout information includes divider network means responsive to the said x- designated coordinate channel signals and y- designated coordinate channel signals for normalizing said signals with respect to the photon energy of their derivative said interaction.

41. The improved system of claim 36 in which said means for deriving readout information includes;

first divider network means coupled to receive a said x- designated coordinate channel signal asserted at a said storage means output; and

second divider network means coupled to receive a said y- designated coordinate channel signal asserted at a said storage means output;

said first and second divider networks being configured and arranged in operative association with the said energy signal output asserted at a said storage means output to effect a division of the values of said coordinate channel signals by the value of their corresponding said energy signal to provide x- and y- designated spatial signals normalized with respect to the said energy signal value;

said second treatment means deriving said readout information from said normalized x- and y- designated spatial signals.