Method and apparatus for detection of radioactive isotopes

Patent metadata

Field	Value
Publication number	US-9645253-B2
Application number	US-201313857584-A
Country	US
Kind code	B2
Filing date	Apr 5, 2013
Priority date	Oct 7, 2010
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A method and apparatus for detecting an isotope. Embodiments can detect radioactive isotopes. Embodiments can utilize a detector that incorporates at least two sub-detectors. Each sub-detector can receive energy from an isotope and create a signal corresponding to the received energy. Each sub-detector can incorporate a detector element, such as a detector element incorporating one or more diodes, a detector element incorporating a crystal, a detector element incorporating a solid-state device, or a detector element incorporating a scintillator. The sub-detectors can be configured such that for each isotope to be detected at least two of the sub-detectors produce different output signals, or readings. In an embodiment, each sub-detector is configured such that when there are at least two sub-detectors exposed to the isotope each of the corresponding readings from the sub-detectors is different from each of the other readings.

First claim

The invention claimed is:

1. A detector, comprising:
at least two sub-detectors,
wherein the at least two sub-detectors are configured such that when the at least two sub-detectors are exposed to radiation from a radioactive isotope the at least two sub-detectors will output a corresponding at least two signals, and
wherein a ratio of a pair of the at least two signals identifies two radioactive isotopes;
a first additional sub-detector,
wherein the first additional sub-detector comprises a first filter having a first activation foil, and
wherein when the first additional sub-detector is exposed to radiation from the radioactive isotope the first additional sub-detector will output a first additional signal that indicates whether neutrons are present in the radiation from the radioactive isotope; and
a processor,
wherein the processor is configured to:
(i) receive two or more of the at least two signals;
(ii) receive the first additional signal;
(iii) determine a ratio of a pair of the two or more of the at least two signals;
(iv) use the ratio of the pair of the two or more of the at least two signals to identify the two radioactive isotopes; and
(v) use the first additional signal to determine whether neutrons are present in the radiation from the radioactive isotope and distinguish between the two radioactive isotopes based on whether neutrons are present in the radiation from the radioactive isotope to identify the radioactive isotope.

2. The detector according to claim 1 ,
wherein each of the corresponding at least two signals are different from each other.

3. The detector according to claim 1 ,
wherein the at least two sub-detectors comprise:
a corresponding at least two detector elements,
wherein the at least two detector elements output a corresponding at least two signals when the at least two sub-detectors are exposed to the radiation from the radioactive isotope.

4. The detector according to claim 3 ,
wherein one or more of the at least two sub-detectors further comprises:
a corresponding one or more filters,
wherein the one or more filters alter the signals of the corresponding one or more detector elements when the at least two sub-detectors are exposed to the radiation from the radioactive isotope.

5. The detector according to claim 3 ,
wherein one or more of the at least two detector elements comprise a corresponding one or more diodes.

6. The detector according to claim 3 ,
wherein one or more of the at least two detector elements comprise a corresponding one or more ion chambers.

7. The detector according to claim 3 ,
wherein one or more of the at least two detector elements comprise a corresponding one or more scintillators.

8. The detector according to claim 7 ,
wherein the one or more of the at least two detector elements comprise:
a corresponding one or more photomultiplier tubes,
wherein the corresponding one or more photomultiplier tubes output a corresponding one or more of the at least two signals when the at least two sub-detectors are exposed to the radiation from the radioactive isotope.

9. The detector according to claim 1 ,
wherein the radiation from the radioactive isotope comprises one or more of the following:
gamma rays, beta particles (electrons), beta particles (positrons), and alpha particles.

10. The detector according to claim 1 ,
wherein the at least two sub-detectors comprises three sub-detectors.

11. The detector according to claim 1 ,
wherein the at least two sub-detectors comprises four to ten sub-detectors.

12. The detector according to claim 3 ,
wherein the at least two detector elements comprise a corresponding at least two diodes.

13. The detector according to claim 4 ,
wherein each of the one or more filters is different from each of the other one or more filters.

14. The detector according to claim 13 ,
wherein each of the at least two detector elements are the same.

15. The detector according to claim 1 ,
wherein the detector is configured to detect any of a plurality of known radioactive isotopes corresponding to a plurality of ratios, and
wherein each ratio of the plurality of ratios is different from each of the other ratios of the plurality of ratios.

16. The detector according to claim 4 ,
wherein each of the one or more filters comprises a material selected from the group consisting of:
tungsten, aluminum, copper, and lead.

17. The detector according to claim 1 ,
wherein the detector is configured to detect a radioactive isotope having radiation from the radioactive isotope with energies in the range of 0.2 MeV to 1 MeV.

18. The detector according to claim 1 ,
wherein the detector is configured to detect a radioactive isotope having radiation from the radioactive isotope with energies in the range of 1 MeV to 2 MeV.

19. The detector according to claim 1 ,
wherein the detector is configured to detect a radioactive isotope having radiation from the radioactive isotope with energies in the range of 10 KeV to 50 KeV.

20. The detector according to claim 1 ,
wherein the radioactive isotope is Cs.

21. The detector according to claim 1 ,
wherein the at least two signals are produced based on simultaneous exposure of the at least two sub-detectors to the radiation from the radioactive isotope.

22. The detector according to claim 1 ,
wherein the at least two sub-detectors are n sub-detectors, where n is a positive integer greater than 1, and
wherein the corresponding n signals result in (n/2)(n−1) ratios.

23. The detector according to claim 1 ,
wherein at least one ratio, for a pair of the at least two sub-detectors corresponding to the pair of the two or more of the at least two signals, corresponding to at least one radioactive isotope is stored in a memory, and
wherein the processor compares the ratio of the pair of the two or more of the at least two signals with one or more of the at least one ratio to identify the radioactive isotope.

24. The detector according to claim 1 ,
wherein the radioactive isotope is selected from the group consisting of:
Pd-123, I-125, Co-60, Mn-54, Co-57, Y-90, and Cd-109.

25. The detector according to claim 1 ,
wherein the radioactive isotope is selected from radioactive isotopes that have a characteristic spectrum.

26. A method of detecting a radioactive isotope, comprising:
providing at least two sub-detectors,
wherein the at least two sub-detectors are configured such that when the at least two sub-detectors are exposed to radiation from a radioactive isotope the at least two sub-detectors output a corresponding at least two signals, and
wherein a ratio of a pair of the at least two signals identifies two radioactive isotopes;
providing a first additional sub-detector,
wherein the first additional sub-detector comprises a first filter having a first activation foil, and
wherein when the first additional sub-detector is exposed to radiation from the radioactive isotope the first additional sub-detector will output a first additional signal that indicates whether neutrons are present in the radiation from the radioactive isotope;
exposing the at least two sub-detectors and the first additional sub-detector to radiation from the radioactive isotope;
identifying the two radioactive isotopes via the ratio of a pair of the at least two signals;
determining whether neutrons are present in the radiation

Assignees

• H Lee Moffitt Cancer Ct & Res

Inventors

• Forster Kenneth M

Classifications

• G01T1/17 Primary

  Circuit arrangements not adapted to a particular type of detector {(pulse-selection circuits H03K, G01R)} · CPC title

• G01V5/0091

  Physics · mapped topic

• G01T1/36

  Measuring spectral distribution of X-rays or of nuclear radiation {spectrometry (pulse selection circuits per se H03K; investigation of materials by radiation diffraction G01N23/20; spectrometer tubes H01J49/00)} · CPC title

• G01T1/167 Primary

  Measuring radioactive content of objects, e.g. contamination (whole body counters G01T1/163) · CPC title

• G01T1/20

  with scintillation detectors · CPC title