System and method for post-exposure dosimetry using electron paramagnetic resonance spectroscopy

Patent metadata

Field	Value
Publication number	US-9255901-B2
Application number	US-200913061423-A
Country	US
Kind code	B2
Filing date	Aug 28, 2009
Priority date	Aug 31, 2008
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

An apparatus and method for triaging patients according to radiation exposure measures electron paramagnetic resonance spectra of fingernails, toenails, and/or teeth. In vivo, radiation induced spectra are obtained from intact fingernails, toenails, or teeth placed within a magnet and with pickup coils over nails between the cut edge at the end of the fingernail and proximal skin or placed adjacent to at least one tooth. The system may also operate in vitro with fingernail clippings. At least three spectra are obtained with one after a delay at above twenty degrees Celsius, and at least one at power levels different from the others. The spectra are used to determine and remove a mechanically induced signal from EPR spectra to determine radiation-induced spectra. The radiation induced spectra are used to determine radiation dose, the dose is compared to triage limits, and a radiological triage tag is printed for the patients.

First claim

What is claimed is:

1. Apparatus for performing electron paramagnetic resonance (EPR) spectrometry in fingernails in vivo comprising:
a magnet;
a device for positioning at least one resonator, upon a dorsal surface of a finger adjacent to at least one fingernail, the resonator having a twisted-pair transmission-line section between a coupling coil and a pickup coil;
a radio frequency measuring device coupled to the coupling coil of the at least one resonator for determining an EPR spectra;
a processing system for computing a radiation dose based upon the EPR spectra, and for comparing the radiation dose to triage limits to determine a triage classification; and
apparatus for outputting the triage classification.

2. The apparatus of claim 1 wherein the device for positioning positions a plurality of resonators, upon dorsal surfaces of a plurality of fingers adjacent to a plurality of fingernails.

3. The apparatus of claim 2 wherein the device for positioning comprises a plurality of finger-cups made of an elastomeric material.

4. The apparatus of claim 1 wherein the magnet provides a magnetic field having strength of at least two thousand gauss, and wherein the magnet comprises a permanent magnet.

5. The apparatus of claim 4 wherein a reference sample comprising manganese or molybdenum is present within the magnetic field.

6. The apparatus of claim 1 wherein the apparatus for outputting the triage classification comprises a printer for printing an output selected from the group consisting of a radiological triage tag and a radiological triage sticker.

7. The apparatus of claim 2 wherein the apparatus measures EPR spectra of at least two fingernails simultaneously.

8. The apparatus of claim 2 wherein the resonators are primarily sensitive to material within two millimeters of the resonator.

9. The apparatus of claim 8 wherein the at least one resonator is a counter-rotating-current resonator.

10. Apparatus for performing electron paramagnetic resonance (EPR) of at least one nail clipping, the nail clipping from a fingernail or a toenail of a subject, comprising:
at least one EPR measurement station comprising;
a magnet for providing a magnetic field and a coupling coil;
an RF generation and measurement system coupled to the coupling coil; and
a processor coupled to the RF generation and measurement system for obtaining EPR spectra of the at least one nail clipping;
wherein the processor obtains first EPR spectra at at least a first and a second power level to estimate a component of a mechanically induced signal in the EPR spectra;
wherein the processor determines a radiation-induced signal by a method comprising subtracting the component of the mechanically-induced signal from at least one of the EPR spectra; and
wherein the processor determines a radiation dose from the radiation induced signal; the apparatus further comprising
a magazine for containing a plurality of clipping-holders, each clipping holder for holding at least one nail clipping; and
apparatus for feeding clipping holders from the magazine into the at least one EPR measurement station;
wherein the magazine is held at a temperature below zero Celsius.

11. The apparatus of claim 10 further comprising a holding bay maintained at a temperature of at least twenty degrees Celsius,
wherein the processor obtains an additional EPR spectra after the nail clipping is held for a time in the holding bay,
wherein the additional EPR spectra is used by the processor together with the first EPR spectra to determine a second component of the mechanically induced signal, and
wherein the method for determining the radiation induced signal further comprises subtracting the second component of the mechanically induced signal from an EPR spectra.

12. The apparatus of claim 11 wherein the processor obtains the additional EPR spectra using an additional EPR measurement station.

13. The apparatus of claim 10 wherein the radiation dose is compared to triage limits to determine a triage category for the subject, and wherein the apparatus further comprises a printer for printing the triage category.

14. The apparatus of claim 13 wherein the printer prints a triage report for the subject, the triage report comprising a report selected from the group consisting of a triage tag, a sticker for application to a triage tag, and a printed report.

15. The apparatus of claim 13 wherein the printer prints the triage category on the clipping holder.

16. The apparatus of claim 11 further comprising a radiation source,
wherein the fingernail clipping is exposed to the radiation source after the additional EPR spectra is obtained, and wherein a fourth EPR spectra is obtained by the processor after the fingernail clipping is exposed to the radiation source.

17. Apparatus for performing electron paramagnetic resonance (EPR) spectrometry in teeth in vivo comprising:
a magnet having sufficient space between poles for a subject's head to be positioned between the poles;
at least one resonator having an encapsulated pickup coil for placement between or adjacent to at least one tooth of the subject, the resonator having a twisted-pair transmission-line section between a coupling coil and the pickup coil;
a radio frequency measuring device coupled to the at least one resonator for determining at least one EPR spectrum;
a processing system for computing a radiation dose based upon the EPR spectrum, and for comparing the radiation dose to triage limits to determine a triage classification; and
apparatus for outputting the radiation dose and the triage classification.

18. The apparatus of claim 17 , the resonator further comprising a second encapsulated pickup coil for placement between or adjacent to at least one additional tooth of the subject.

19. The apparatus of claim 17 wherein a reference sample comprising manganese or molybdenum is present within the magnetic field.

20. The apparatus of claim 17 wherein the apparatus for outputting the triage classification comprises a printer for printing an output selected from the group consisting of a radiological triage tag and a radiological triage sticker.

21. The apparatus of claim 17 wherein the apparatus measures EPR spectra of at least two teeth simultaneously.

Assignees

• Swartz Harold M
• Gui Jiang
• He Xiaoming
• Leniewski Piotr
• Flores Roberto J Nicolalde
• Williams Benjamin B
• Wilcox Dean E
• Dartmouth College

Inventors

• Swartz Harold M
• Gui Jiang
• He Xiaoming
• Leniewski Piotr
• Flores Roberto J Nicolalde
• Williams Benjamin B
• Wilcox Dean E

Classifications

• G01R33/60

  using electron paramagnetic resonance (G01R33/24, G01R33/62 take precedence) · CPC title

• G01N24/10 Primary

  by using electron paramagnetic resonance (G01N24/12 takes precedence) · CPC title