BACKGROUND

1. Field of the Invention

The present invention generally relates to systems and methods for portable assessment of labeled probes, and in particular labeled probes that are to be followed for extended periods of time.

2. Description of Background

Medical imaging techniques that rely on detection of emissions from tracers originating from within the body of the subject being imaged are widely used for diagnosis of various diseases. Nuclear physics-based molecular imaging techniques, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) allow functional imaging of subjects at the molecular level based on the use of radioactive isotopes. For example, SPECT is based on the use of radioisotopes that emit gamma rays and PET is based on the use of radioisotopes that emit positrons, which annihilate to produce gamma rays. In contrast to nuclear imaging techniques, fluorescence based optical imaging techniques do not involve ionizing radiation such as gamma rays. Instead, fluorescence imaging relies on the excitation of fluorophore tracers by a light source that results in the absorption of photons by the fluorophores, and the subsequent detection of photons emitted by the fluorophores as they decay from their excited state. A disadvantage of the various imaging techniques that rely on internal tracers, such as PET, SPECT and fluorescence imaging, is that they rely on the use of large scale and expensive scanners for the detection of emissions from the internal tracers, thereby requiring costly visits to radiology clinics.

SUMMARY OF THE INVENTION

Methods and devices disclosed herein provide a non-restrictive, portable photon-counting device which can be worn by a subject, e.g., on the head, arm, wrist and/or ankle, which can, in embodiments, allow tracking in the subjects body of a labeled probe over an extended period of time, e.g., over a period of days, or, e.g., for substantially longer than the time period for which a patient is typically monitored in a PET scan.

In on aspect, the invention features, an apparatus for detecting emissions from a labeled probe disposed within the body of a living subject. The apparatus comprises:

a detector configured to detect emissions from the labeled probe and to generate a signal based on the detected emissions,

a transmitter configured to transmit the signal to a processor, and

a biasing member configured to position the detector on the subject's body and allow the detector to be wearable by the living subject,

wherein said apparatus is configured for detecting emissions and transmitting signals for at least X days, wherein X is 2.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, said apparatus weighs less than 250, 500, 1,500, 2,000, 3,000 grams.

In an embodiment, said apparatus is configured such that the subject is able to walk while wearing the apparatus.

In an embodiment, said apparatus is configured such that the subject has his or her full range of motion with one or both arms while wearing the apparatus.

In an embodiment, said apparatus is configured such that the detector does not move relative to the region of the subject's body from which it detects emissions when the subject walks.

In an embodiment, all elements of the apparatus are disposed outside the subject's body.

In an embodiment, no element of the apparatus is transdermal or implanted in the subject's body.

In an embodiment, said apparatus is configured to allow detection of emissions from a preselected region of said subject.

In an embodiment, the apparatus comprises a plurality of detectors.

In an embodiment, each of the detectors of the plurality of detectors is configured to detect emissions from a preselected region of the subject.

In an embodiment, the apparatus comprises a first detector configured to allow detection of emissions from a first preselected region of said subject and a second detector first detector configured to allow detection of emissions from a second preselected region of said subject.

In an embodiment, said first and second regions overlap.

In an embodiment, said first and second regions do not overlap.

In an embodiment, said first and second regions are coextensive.

In an embodiment, said apparatus comprises N detectors, wherein N is equal to at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, or 30.

In an embodiment, each detector is configured to allow detection of emissions from a preselected region.

In an embodiment, at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 of said preselected regions overlaps with one or more other preselected region.

In an embodiment, at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 of said preselected regions does not overlap with another preselected region.

In an embodiment, a plurality of preselected regions are configured such that detection of emissions from them allows determination the levels, e.g., the levels over time, of the labeled probe.

In an embodiment, one or a plurality of detectors are configures such that emissions from the brain, and optionally a region away from the brain, e.g., the arm or leg can be detected.

In an embodiment, a plurality of detectors is arranged such that the plurality of signals form an image indicative of a location of the labeled probe within the living subject.

In an embodiment, the plurality of detectors is arranged in a ring configuration.

In an embodiment, the apparatus comprises a first detector having a preselected region that includes a target region or structure and a second first detector having a preselected region that does not includes the target region or structure.

In an embodiment, the detector is configured to detect emissions in at least one of a gamma ray and an infrared spectral range.

In an embodiment, the detector comprises a charge coupled device having a scintillation crystal, e.g., a removable scintillation crystal.

In an embodiment, the detector comprises one of a Geiger counter, an avalanche photodiode and a charge coupled device.

In an embodiment, said apparatus comprises a self-contained power source.

In an embodiment, the power source provides power for the detector and the transmitter.

In an embodiment, a detector is disposed on a first biasing member and the power source is disposed on a second biasing member.

In an embodiment, the transmitter is configured to transmit the signal wirelessly and the processor is located at a remote site.

In an embodiment, the transmitter is configured to receive signals from a plurality of detectors.

In an embodiment, the apparatus comprises a plurality of transmitters including the transmitter, each transmitter of the plurality of transmitters corresponding to at least one detector of the plurality of detectors and being configured to transmit at least one signal of the plurality of signals to the processor.

In an embodiment, said biasing member disposes a detector on the body of the subject.

In an embodiment, the biasing member surrounds a portion of the subject's body.

In an embodiment, the biasing member is configured to have a circumference, and the circumference is adjustable.

In an embodiment, the biasing member is formed from flexible material and is configured to be disposed around a portion of the subject's body.

In an embodiment, the portion of the subject's body is selected from the head, neck, arm, wrist, leg, ankle, abdomen, chest, or stomach.

In an embodiment, the biasing member comprises a band.

In an embodiment, the band is formed of stretchable material.

In an embodiment, the biasing member comprises one of a head-band, an arm-band, a wrist-band, an ankle-band and a waist-band.

In an embodiment, the apparatus further comprises a plurality of biasing members, each biasing member of the plurality of biasing members disposes at least one detector of the plurality of detectors and each biasing member further being configured to be wearable proximate to a different portion of the living subject.

In an embodiment, the apparatus further comprises a first biasing member for disposing a detector on the subject's body and a second biasing member for disposing a transmitter on the subject's body.

In an embodiment, the biasing member is configured to be wearable in proximity to a target portion of the living subject and the detector is configured to generate the signal indicative of the of the labeled probe within the target portion, the labeled probe being targeted to the target portion of the living subject.

In an embodiment, a plurality of detectors are configured with a biasing member such that the plurality of signals indicative of the pharmacokinetic property form an image indicative of a location distribution of the labeled probe within the living subject.

In an embodiment, a plurality of detectors is configured with a biasing member such that the plurality of signals are indicative of the concentration of the labeled probe in a preselected region or structure.

In an embodiment, said signal is indicative of the health or disease status of the subject.

In an embodiment, said signal is indicative of a target compound or structure bound by the labeled probe.

In an embodiment, said signal is indicative of the presence or level of a disorder, or disease state.

In an embodiment, said disorder, or disease state is selected from a neoplastic disorder, e.g., cancer, inflammation, a neurological disorder, e.g., a neurodegenerative disorder, e.g., Alzheimer's Disease.

In an embodiment, said signal is indicative of the presence of the labeled probe in a preselected region of said subject.

In an embodiment, the signal is indicative of the concentration of the labeled probe as a function of time.

In an embodiment, said signal is indicative of a pharmacokinetic property of the labeled probe or precursor thereof.

In an embodiment, said signal is indicative of a pharmacodynamic property of the labeled probe or precursor thereof.

In an embodiment, said signal is indicative of one or more of absorption, distribution, metabolism, and excretion of the labeled probe.

In an embodiment, said signal is indicative of the time course of one or more of absorption, distribution, metabolism, and excretion of the labeled probe.

In an embodiment, said labeled probe is a product of a reaction involving a precursor labeled probe administered to said subject.

In an embodiment, said signal is indicative of the concentration of the labeled probe at a site.

In an embodiment, said signal is indicative of the concentration of the labeled probe at a site and an effect of the labeled probe.

In an embodiment, said labeled probe is configured such that, e.g., with a single administration, it produces emissions detectable by the detector for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, said labeled probe is configured such that, upon 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or 14 administrations, it produces emissions detectable by the detector for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, said labeled probe is has affinity for a compound or structure in the subject's body.

In an embodiment, said labeled probe comprises and antibody molecule, a ligand molecule, receptor a receptor molecule, or small molecule having affinity for a target.

In an embodiment, said labeled probe is a substance administered to said subject.

In an embodiment, said labeled probe comprises a product of a reaction involving a precursor labeled probe administered to said subject.

In an embodiment, said labeled probe comprises a product arising from metabolism of a precursor labeled probe administered to said subject.

In an embodiment, said labeled probe comprises a moiety that emits a gamma, a positron, or a photon.

In an embodiment, said labeled probe comprises a moiety that emits in the infrared range.

In an embodiment, the moiety comprises one of a radionuclide and a fluorophore.

In an embodiment, the moiety is covalently bonded to an atom of the probe.

In an embodiment, the labeled probe emits emissions in at least one of a gamma ray and an infrared spectral range.

In an embodiment, the labeled probe comprises a therapeutic agent.

In an embodiment, the labeled probe comprises a metabolized therapeutic agent.

In an embodiment, the labeled probe comprises a diagnostic agent.

In an embodiment, the labeled probe comprises a metabolized diagnostic agent.

In an embodiment, the apparatus further comprises:

a plurality of detectors, the plurality of detectors being configured to detect emissions from the labeled probe and to generate a plurality of signals, each detector of the plurality of detectors being configured to generate a respective signal of the plurality of signals based on emissions detected by that detector.

In an embodiment, the plurality of signals form an image indicative of a concentration of the labeled probe within the living subject.

In an embodiment, a plurality of detectors are arranged within a biasing member such that the plurality of signals indicative of the pharmacokinetic property form an image indicative of a location distribution of the labeled probe within the living subject.

In an embodiment, said preselected region comprises a region of the brain.

In an embodiment, the apparatus comprises a plurality of detectors configured to collect emissions from the brain.

In an embodiment, a plurality of detectors configured and preselected regions configured such that at least 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 99% of the brain falls within said regions.

In an embodiment, a plurality of detectors are arranged within a biasing member such that the plurality of signals indicative of the pharmacokinetic property form an image indicative of a location distribution of the labeled probe within the living subject.

In an embodiment, the plurality of detectors is arranged in a ring configuration.

In an embodiment, the biasing member disposes a plurality of detectors around the circumference of the head, the biasing member being configured to be wearable around the head of the living subject for measuring emissions from the labeled probe within the brain of the living subject.

In an embodiment, at least 2, 3, 4, 5, 6, 7, or 8 detectors are disposed around the circumference of the head.

In an embodiment, a plurality of detectors is configured with a biasing member such that plurality of detectors is arranged around the circumference of a portion of the body.

In an embodiment, the portion of the body is the neck, chest, stomach, arm, leg, wrist, or ankle.

In another aspect, the invention features, a method for assessment of a labeled probe disposed within the body of a subject, the method comprising:

providing or acquiring an apparatus for the detection of a labeled probe wherein the apparatus comprises:a detector configured to detect emissions from a labeled probe and togenerate a signal based on the detected emissions,optionally, a transmitter configured to transmit the signal to a processor, anda biasing member configured to allow the detector to be wearable by the living subject; and

placing the detector on the subjects body such that emissions from the labeled probe can be detected,

wherein said apparatus is configured to detect emissions and transmit signals for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, the labeling moiety, frequency of administration of the labeled probe, half-live of the labeling moiety, and half-life, e.g., serum half life, of the probe, are selected so as to allow for emission, detection and analysis over a sustained period of time.

In an embodiment, the labeling moiety, half-live of the labeling moiety, and half-life, e.g., serum half life, of the probe, are selected so as to allow for emission, detection and analysis over a sustained period of time, upon a single administration of the labeled probe, e.g., for at least X days where X is 1.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, the method further comprises:

receiving the signal indicative of the detection of emissions from the labeled probe.

In an embodiment, emissions are detected for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, said signal is generated, transmitted, or received, for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, the detector is placed on the subject's body by the subject.

In an embodiment, the detector is place on the subject's body by a person other than the subject.

In an embodiment, the method comprises adjusting the biasing member to fit the subject's body.

In an embodiment, the method comprises adjusting the biasing member to fit the subject's head, arm, wrist, chest, stomach, leg, or ankle.

In an embodiment, the method comprises adjusting the circumference of the biasing member to fit the apparatus to the subject's body.

In an embodiment, the method comprises adjusting the circumference of the biasing member to fit the apparatus to the subject's head, arm, wrist, chest, stomach, leg, or ankle.

In an embodiment, the method comprises administering the labeled probe or a precursor of the labeled probe to the subject.

In an embodiment, the method comprises:

generating, transmitting, or receiving a first signal indicative of the detection of emissions from the labeled probe; and

generating, transmitting, or receiving a second, or subsequent, signal indicative of the detection of emissions from the labeled probe.

In an embodiment, at least 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 24, 48, 72, or 96 hours elapses between generating, transmitting, or receiving a first signal and generating, transmitting, or receiving the second signal or subsequent signal.

In an embodiment, at least X days, wherein X is 1 or greater, elapses between generating, transmitting, or receiving the first signal and generating or receiving the second signal or subsequent.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, the apparatus is not removed from the subject's body between generating, transmitting, or receiving the first signal and generating or receiving the second signal or subsequent signal.

In an embodiment, the apparatus is removed from the subject's body between generating, transmitting, or receiving the first signal and generating, transmitting, or receiving the second signal or subsequent signal.

In an embodiment, the method further comprises:

generating, transmitting, or receiving a first signal indicative of the detection of emissions from the labeled probe during a first time period; and

generating, transmitting, or receiving a second signal indicative of the detection of emissions from the labeled probe during a second, or subsequent, time period.

In an embodiment, at least 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 24, 48, 72, or 96 hours elapses between the end of the first time period and the beginning of the second, or subsequent, time period.

In an embodiment, at least X days, wherein X is 1 or greater, elapses between the end of the first time period and the beginning of the second, or subsequent, time period.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, the method comprises generating, transmitting, or receiving a signal indicative of the detection of emissions from the labeled probe in the time period between the first and second, or subsequent, time periods.

In an embodiment, the apparatus is not removed from the subject's body between the first time period the second, or subsequent, time period.

In an embodiment, the apparatus is removed from the subject's body between the first time period the second, or subsequent, time period.

In an embodiment, the method further comprises:

generating, transmitting, or receiving signals indicative of the detection of emissions from the labeled probe during at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, or 60 time periods.

In an embodiment, said time periods are separated by at least 1, 10, 30, or 60 minutes.

In an embodiment, the method further comprises generating an assessment of the labeled probe.

In an embodiment, the signal is indicative of the presence of the labeled probe in a preselected region of said subject.

In an embodiment, the signal is indicative of the concentration of the labeled probe as a function of time.

In an embodiment, said signal is indicative of a pharmacokinetic property of the labeled probe.

In an embodiment, said signal is indicative of a pharmacodynamic property of the labeled probe.

In an embodiment, the signal is indicative of one or more of absorption, distribution, metabolism, and excretion of the labeled probe.

In an embodiment, said signal is indicative of the time course of one or more of absorption, distribution, metabolism, and excretion of the labeled probe.

In an embodiment, said labeled probe is a product of a reaction involving a precursor labeled probe administered to said subject.

In an embodiment, said signal is indicative of the concentration of the labeled probe at a site.

In an embodiment, said signal is indicative of the concentration of the labeled probe at a site and an effect of the labeled probe.

In an embodiment, said signal is indicative of the health or disease status of the subject.

In an embodiment, said signal is indicative of the presence, incidence, stage, progress, or level of a disorder, or disease state.

In an embodiment, said signal is indicative of response to a treatment.

In an embodiment, said disorder, or disease state is selected from a neoplastic disorder, e.g., cancer, inflammation, a neurological disorder, e.g., a neurodegenerative disorder, e.g., Alzheimer's Disease.

In an embodiment, the method further comprises:

receiving the signal indicative of the detection of emissions from the labeled probe; and

generating a health status of the living subject based on the signal.

In an embodiment the method further comprises:

providing a plurality of bands for wearing proximate a plurality of target portions of the living subject, each band to be worn proximate a respective target portion of the plurality of target portions, each band including at least one detector for detecting emissions from the labeled probe and for generating at least one signal indicative of the detection of emissions.

In an embodiment, the method further comprises:

receiving a plurality of signals from the plurality of bands, the plurality of signals including the at least one signal from each band of the plurality of bands; and

generating an assessment of the pharmacokinetics of the probe within the plurality of target portions based on the plurality of signals.

In an embodiment, generating the assessment further includes generating at least one of a location distribution and a concentration distribution of the probe based on the plurality of signals.

In an embodiment, the method further comprises:

labeling the probe or precursor probe with a label.

In another aspect, the invention features, a method for assessment of a labeled probe disposed within the body of a subject, the method comprising:

receiving, from a wearable apparatus comprising a photon detector, a signal based on the detection of emissions from the labeled probe disposed within the body of the subject;

generating an assessment of the labeled probe based on the signal,

thereby assessing a labeled probe.

In an embodiment, the signal is transmitted wirelessly.

In an embodiment, the apparatus comprises:a detector configured to detect emissions from the labeled probe and to generate a signal based on the detected emissions,optionally, a transmitter configured to transmit the signal to a processor, anda biasing member configured to allow the detector to be wearable by the living subject.

In an embodiment, the assessment is generated with a processor configured to receive the signal and to generate an assessment of the labeled probe based on the signal.

In another aspect, the invention features, a method for assessment of a labeled probe, the method comprising:

detecting emissions from the labeled probe, administered, e.g., injected, into a living subject using a detector worn by the living subject;

generating a signal based on the detecting, the signal being indicative of a pharmacokinetic property of the labeled probe; and

transmitting the signal to a processor for assessing the pharmacokinetic property of the labeled probe.

In an embodiment, the method further comprises:

administering the labeled probe or a precursor of the labeled probe into the living subject.

In an embodiment the method further comprises:

receiving the signal by the processor located at a remote site; and

processing the signal to assess the pharmacokinetic property of the labeled probe.

In an embodiment, the labeling moiety, frequency of administration of the labeled probe, half-live of the labeling moiety, and half-life, e.g., serum half life, of the probe, are selected so as to allow for emission, detection and analysis over a sustained period of time.

In an embodiment, the labeling moiety, half-live of the labeling moiety, and half-life, e.g., serum half life, of the probe, are selected so as to allow for emission, detection and analysis over a sustained period of time, upon a single administration of the labeled probe, e.g., for at least X days where X is 1.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, the method further comprises: receiving the signal indicative of the detection of emissions from the labeled probe.

In an embodiment, emissions are detected for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, said signal is generated, transmitted, or received, for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In another aspect, the invention features, a system for assessment of a labeled probe in living subject, the system comprising:

a detector configured to detect emissions from the labeled probe and to generate a signal based on the detected emissions,

a transmitter configured to transmit the signal to a processor,

a biasing member configured to allow the detector to be wearable by the living subject; and

a processor configured to receive the signal and to generate an assessment of the labeled probe based on the signal.

In an embodiment, the labeling moiety, frequency of administration of the labeled probe, half-live of the labeling moiety, and half-life, e.g., serum half life, of the probe, are selected so as to allow for emission, detection and analysis over a sustained period of time.

In an embodiment, the labeling moiety, half-live of the labeling moiety, and half-life, e.g., serum half life, of the probe, are selected so as to allow for emission, detection and analysis over a sustained period of time, upon a single administration of the labeled probe, e.g., for at least X days where X is 1.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90 or more days.

In an embodiment, the method further comprises:

receiving the signal indicative of the detection of emissions from the labeled probe.

In an embodiment, emissions are detected for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

In an embodiment, said signal is generated, transmitted, or received, for at least X days, wherein X is 1 or greater.

In an embodiment, X is selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

A kit comprising:a) an apparatus for detecting emissions from a labeled probe disposed within the body of a living subject, the apparatus comprising one or more or all of:

a detector configured to detect emissions from the labeled probe and to generate a signal based on the detected emissions,

a transmitter configured to transmit the signal to a processor, and

a biasing member configured to position the detector on the subject's body and allow the detector to be wearable by the living subject, wherein said apparatus is configured for detecting emissions and transmitting signals for at least X days, wherein X is 1;b) a labeled probe, or precursor thereof, suitable for allowing detection of emissions from the subject for at least X days, wherein X is 1, e.g., by one, two, or three administrations.

In an embodiment, X is selected, independently, from 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 90, or more days.

The devices and methods described herein provide for remote assessment of subject health status, disease state, and drug pharmacokinetics.

Embodiments of the invention provide a non-restrictive, portable photon-counting device which can be worn by a subject, e.g., on the head, arm, wrist and/or ankle, which can, in embodiments, allow tracking in the subjects body of a labeled probe over an extended period of time, e.g., over days or weeks, e.g., substantially longer than the time period for which a patient is typically monitored in a PET scan. The device allows quantitative kinetic measurement of molecular compounds in a living subject. Compounds of interest can to be labeled with select radionuclides or fluorophores enabling the production of emissions across a broad spectrum of energies. These emissions are subsequently detected by the photon-counting device in any location and remotely reported back to researchers or clinicians via computer or mobile telecommunications devices. Typically, the probe and the labeled moiety are selected such that the combination of half-life in the serum (or other relevant compartment) and the half-life of the emitter together allow monitoring the labeled probe for days, weeks or even months.

Devices and methods of provided herein allow for minimally invasive methodologies to characterize the pharmacokinetic and pharmacodynamic behavior of diagnostic and therapeutic agents inside a living subject's body. Nuclear physics-based molecular imaging techniques, such as positron emission tomography (PET) or single photon emission computed tomography (SPECT), and fluorescence based optical imaging techniques offer such methodologies. PET and SPECT imaging are highly sensitive and have demonstrated great scientific and clinical value. In current practice however, both techniques require access to highly specialized clinic based scanners and radiologists thus adding significant expense. In the case of longer half-life isotope labeled compounds, repeated returns to the imaging facility are required for serial imaging scans of a subject. This poses logistical and economic constraints and thereby limits the full potential of PET and SPECT methodologies.

Fluorescence-based imaging techniques are widely used in preclinical research. Because they do not require use of a radioactive tracer, fluorescence methods are actively being pursued for clinical translation where they will face similar requirements and restrictions as PET and SPECT.

Devices and methods provided herein mitigate these restrictions by providing a portable photon-counting device that can minimize the need for costly hospital or imaging clinic based nuclear medicine/radiology studies, and can allow for improved exploitation of long half-life radioisotopes and/or fluorophores. Photon-monitoring devices enable low-cost, quantitative, non-invasive nuclear assays of drug and diagnostic agent kinetics within a subject over multiple biological half-lives. By allowing for portability and remote monitoring, devices and methods described herein can also bring the medical benefits of PET and SPECT technologies to parts of the world where scanners and radiologists are not readily available.

