Nuclear cardiac blood volume detecting apparatus

• US 4,197,836 A
• Filed: 01/25/1978
• Issued: 04/15/1980
• Est. Priority Date: 11/06/1975
• Status: Expired due to Term

• Current Assignee: BIOS Corporation (Melco Holdings Incorporated)
• Original Assignee: BIOS Corporation (Melco Holdings Incorporated)
• Inventors: Wake, Robert H., Wagner, Henry N.
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US05/872,069
• Time in Patent Office: 811 Days
• Field of Search: 128/2 A, 128/2.05 F, 128/2.05 V, 250/363 S
• US Class Current: 600/431
• CPC Class Codes: A61B 5/02755 Radioactive tracers
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: A61B 6/4057 by using radiation sources located in the interior of the body A61B6/037 takes precedence
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/161 Applications in the field of nuclear medicine, e.g. in vivo counting apparatus for radiation diagnosis A61B6/00

Abstract

A built up image illustrating blood volume in the heart versus time taken over many cardiac cycles is produced by continuously displaying a graph of cumulative data indicating the amount of radioactivity from a tracer in the blood detected in the heart during each of a series of intervals into which the average cardiac period is divided. The parallel lines of a raster scan display correspond respectively to the memory channels. The count stored in a particular memory channel causes the video signal for the corresponding line to be maintained at a binary level for a corresponding time interval thus generating a bar graph in which the length of each bar indicates the amount of radioactivity sensed during the corresponding interval of the cardiac cycle. As each memory channel accumulates radioactivity data with each successive cardiac cycle, each bar displayed in the bar graph lengthens to indicate the cumulative activity until an interpretable curve is obtained.

Claims

1. A system for displaying the variation in radioactivity within a patient'"'"'s cardiac cycle from a tracer substance in the blood comprising:

detector means for providing an output indicative of the amount of radiation emitted from a selected location in the heart blood pool;

timing means for determining successive sampling intervals;

nuclear event integrator means responsive to said timing means and said detector means output for producing an output indicative of the amount of said radiation detected in each successive sampling interval;

addressable N channel cumulative memory means for accumulating a representation of the total amount of radiation indicated by said integrator means for every nth sampling interval in a corresponding one of N memory channels;

heart beat responsive means for generating a synchronizing pulse at the patient'"'"'s heart rate;

memory channel addressing means responsive to said timing means and said heart beat responsive means for incrementing the input channel address for said memory means with each sampling interval in a repeating sequence of N predetermined channel addresses in which each successive sequence is initiated by said synchronizing digital pulse; and

means for displaying simultaneously the contents of all N channels of said memory means in the format of N adjacently spaced visible indicia each having a height above a common axis according to the current cumulative total represented in the corresponding memory channels respectively.

2. The system of claim 1 wherein said displaying means includes means for producing said visible indicia in the form of N adjacent parallel lines each having lengths corresponding to the cumulative total represented in the corresponding memory channels respectively.

3. The system of claim 1, wherein said detector means includes transducer means for producing output pulses indicative of radiation emitted from a selected location in the heart blood pool and analyzer means responsive to the output pulses of said transducer means for producing a digital pulse output indicative of a particular kind of radiation;

and said integrator means includes a nuclear event counter means for counting the number of digital pulses in each successive sampling interval.

4. The system of claim 1, wherein said memory means includes an N channel addressable read/write digital memory and two-input adder means having one input connected to the memory readout and the other input connected to the nuclear event integrator means for producing the sum of the two inputs as the data input to said memory for providing a cumulative total in said memory of the output of said nuclear event integrator means.

5. The system of claim 1, wherein said displaying means includes a video display, means for generating a raster scan in said display comprising a sequence of at least N adjacent line sweeps, and comparator means synchronized with said raster scan for generating a digital data video signal beginning approximately at the start of each line sweep and terminating during the line sweep after an interval corresponding to the cumulative total in the corresponding memory channel of said memory means to produce a composite data image on said video display.

6. The system of claim 5, wherein said comparator means includes means for interrogating the channels of said memory means at the rate of said raster scan.

7. The system of claim 5, wherein said displaying means further includes means for generating a digital gradicule video signal to produce a grid pattern of lines on said display, and EXCLUSIVE OR means for gating said data and gradicule video signals to said display such that coincidence of the two signals results in reduced video signal so that the grid pattern is not obscured by said data image.

8. The system of claim 1, further comprising means for adjusting said sampling interval over a predetermined range to allot N consecutive sampling intervals to the patient'"'"'s cardiac period.

9. The system of claim 1, further comprising means for selectively dividing the number of memory channels in said memory means and correspondingly lengthening the sampling interval to lower the resolution of the display.

10. The system of claim 1, further comprising means for disconnecting said memory channel addressing means from said synchronizing pulse and for sequencing said memory means once through said N channels on command.

11. A system for displaying the variation in radioactivity within a patient'"'"'s cardiac cycle from a tracer substance in the blood comprising:

detector means for providing an output indication of the amount of radiation emitted from a selected location in the heart blood pool;

timing means for determining a sampling interval;

means for producing an output indicative of the cumulative amount of the radiation in each corresponding sampling interval over a number of cardiac cycles.

12. The system of claim 11, further comprising means for synchronizing said sampling intervals with the patients cardiac cycle.

13. The system of claim 11, further comprising means responsive to said producing means for displaying a graphical feature for each interval, which for a given interval is indicative of the current sum or previous outputs said detector means during said given interval.