Real time sensor for therapeutic radiation delivery

• US 5,704,890 A
• Filed: 05/31/1995
• Issued: 01/06/1998
• Est. Priority Date: 05/31/1995
• Status: Expired due to Term

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Craig, Richard A., Bliss, Mary, Reeder, Paul L.
• Primary Examiner(s): Lacyk, John P.
• Application Number:
  US08/455,586
• Time in Patent Office: 951 Days
• Field of Search: 128/597-99, 600/1-8
• US Class Current: 600/1
• CPC Class Codes: A61N 5/1048 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: A61N 5/1071 for verifying the dose delivered by the treatment plan
• CPC Class Codes: G01T 1/201 using scintillating fibres

Abstract

The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body.

Claims

1. An apparatus for determining the relative dose rate of a therapeutic radiation received by a patient, comprising:

(a) a probe assembly comprising;

(i) at least one probe for placement near on internal to the patient, said probe having

a coating,

an insertion end and an attaching end,

an active portion within said probe constructed of a scintillation material, said scintillation material producing a signal upon being exposed to said therapeutic radiation;

(ii) a probe connecting cable, having a first end and a second end,

a signal analysis and readout unit connected to said probe with said probe connecting cable connected to a first electronic port of the signal analysis and readout unit;

(iii) said attaching end attached to said first end;

(iv) said second end being attached to the signal analysis and readout unit,

said signal analysis and readout unit receiving signals from said scintillation material via said probe connecting cable, said signal analysis and readout unit having a signal detection and calculation means therein;

wherein said signal and analysis unit determines said relative dose rate that is indicated on the signal analysis and readout unit, and is representative of the radiation dose received at the location of said probe.

2. The apparatus as recited in claim 1, further comprising:

(b) a location assembly comprising;

(i) an element matrix comprising a plurality of vertical sensing elements and a plurality of horizontal sensing elements;

(ii) said vertical and horizontal sensing elements each constructed of scintillator material, each of said horizontal and vertical sensing elements having an assembly end and a free end;

(iii) an element matrix connecting cable, having a first end and a second end;

(iv) said assembly end attached to said first end;

(v) said second end being attached to a second electronic port of the signal analysis and readout unit,

said signal analysis and readout unit receiving signals from said scintillation material via said element matrix connecting cable, said signal analysis and readout unit having a signal detection and calculation means therein;

wherein when said patient is placed in a known relative position to said element matrix said signal analysis unit indicated the relative location of said radiation dose.

3. The apparatus in claim 1 wherein the radiation dose is selected from the group comprising:

thermal neutrons, epithermal neutrons, fast neutrons, gamma rays, or x-rays.

4. The apparatus in claim 1 wherein said probe assembly comprises an insertion probe and an exit probe, whereby the radiation dose rate is determined by the radiation dose difference between the two probes.

5. The apparatus in claim 1 wherein the signal analysis and readout unit comprises a solid state optical detector and a comparison and data storage unit which receives electrical signals from the solid state optical detector, and an indicator unit which receives electrical signals from the comparison and data storage unit and indicates the dose and relative location received by the patient.

6. The apparatus in claim 5 wherein the optical detector is a photo-multiplier tube.

7. The apparatus in claim 5 wherein the readout device is an analog indicator.

8. The apparatus in claim 5 wherein the readout device is a digital indicator.

9. The apparatus in claim 1 wherein the active portion is constructed of an organic fiber optic material.

10. The apparatus in claim 1 wherein organic fiber optic material is plastic.

11. The apparatus in claim 1 wherein the active portion is constructed of an inorganic fiber optic material.

12. The apparatus in claim 11 wherein the active portion is constructed of a fiber optic glass doped with a dopant.

13. The apparatus in claim 12 wherein the dopant is ₃ Li⁶.

14. The apparatus in claim 9 wherein the active portion is constructed of a fiber optic glass doped with a light-emitting activator ion.

15. The apparatus in claim 14 wherein the activator ion is Ce³⁺.

16. The apparatus in claim 2 wherein the sensing elements are constructed of an organic fiber optic material.

17. The apparatus in claim 1 wherein the organic fiber optic material is plastic.

18. The apparatus in claim 2 wherein the sensing elements are constructed of an inorganic fiber optic material.

19. The apparatus in claim 17 wherein the sensing elements are constructed of a fiber optic glass doped with a dopant.

20. The apparatus in claim 19 wherein the dopant is ₃ Li⁶.

21. The apparatus in claim 2 wherein the vertical sensing elements and the horizontal sensing elements are substantially at right angles.

22. The apparatus in claim 2 wherein the vertical sensing elements and the horizontal sensing elements are substantially at an acute angle.

23. The apparatus in claim 2 wherein the element matrix is a series of ring elements.

24. The apparatus in claim 2 wherein the element matrix is a series of ring elements used concurrently with a series of vertical sensing elements.

25. The apparatus in claim 2 wherein the element matrix is a series of ring elements concurrently with a series of horizontal sensing elements.

26. The apparatus in claim 2 wherein said sensing elements are segmented into portions, each segment connected by a connecting cable to the signal and analysis and readout unit.

27. The apparatus in claim 1 wherein the connecting cables are constructed of an organic fiber optic material.

28. The apparatus in claim 1 wherein the organic fiber optic material is plastic.

29. The apparatus in claim 1 wherein the connecting cables are constructed of an inorganic fiber optic material.

30. The apparatus in claim 26 wherein the connecting cables are constructed of a fiber optic glass doped with a dopant.

31. The apparatus in claim 30 wherein the dopant is ₃ Li⁶.

32. The apparatus in claim 1 wherein the connecting cables are constructed of an electrical conductor.

33. The apparatus in claim 1 wherein background signal noise is reduced by means of a coincidence analysis unit.

35. The apparatus in claim 1 wherein the location of a radiation flux interaction along the vertical sensing element and horizontal sensing element is determined by:

measuring a first pulse height h1 received at a first segment end,

measuring a second pulse height h2 received at a second segment end,

the difference in said pulse heights indicating;

a distance d1 from one segment end, and

a distance d2 from said second segment end.

36. The apparatus in claim 1 wherein the location of a radiation flux interaction along the probe is determined by:

measuring a first pulse height h1 received at a first segment end,

measuring a second pulse height h2 received at a second segment end,

the difference in said pulse heights indicating;

a distance d1 from one segment end, and

a distance d2 from said second segment end.

34. An apparatus for determining the relative location and dose rate of therapeutic radiation received by a patient, comprising:

(a) a probe assembly comprising;

(i) at least one probe placed in the vicinity of the patient, said probe having

a coating on said probe,

an insertion end and an attaching end, and

an active portion constructed of a scintillation material;

(ii) a probe connecting cable, having a first end and a second end;

(iii) said attaching end attached to said first end;

(iv) a signal and analysis readout unit attached to said second end;

wherein said radiation dose rate is determined and indicated on the signal analysis and readout unit;

(b) a location assembly comprising;

(i) an element matrix of a plurality of vertical sensing elements and a plurality of horizontal sensing elements;

(ii) said vertical and horizontal sensing elements each constructed of scintillator material,

(iii) said horizontal and vertical sensing elements having a first assembly end and a second assembly end;

(iii) a plurality of element matrix connecting cables, having a first end and a second end;

(iv) a signal analysis and readout unit connected to said probe with said second end being attached to the signal analysis and readout unit;

(v) said second end of said plurality being attached to a coincidence analysis unit;

(vi) said coincidence analysis unit emits and electrical signal only upon a confirmed detection event occurring in said sensing elements, said electrical signal being received by the signal analysis and readout unit;

wherein when said patient is placed relative to said element matrix said signal analysis unit indicates the relative location of said radiation dose.