In vivo measurement system and method for the localized measurement of radiotracer concentration in the body
Various embodiments of a device for in-vivo measurements radiopharmaceuticals used for diagnosis and monitoring of radiotherapy are presented. In some embodiments, the present disclosure relates to a device having a cannula that may include a measurement chamber, a radiation detector and a delivery lumen, wherein the device may be used to both deliver material to the patient (e.g., radiotracers used in radiopharmaceuticals) and measure levels and concentrations of radioactive material in, for example, the patient's blood both during and after administration of the radioactive material. In some embodiments, a plunger may be utilized to draw blood through a first opening into the measurement chamber and then return it to the bloodstream. In some embodiments, particle absorbing materials may be used to limit measurements to materials within the measurement chamber or other area of interest.
1 . A device for localized measurement of radiotracers in a blood vessel of interest, the device comprising a cannula sized and configured for insertion into the blood vessel of interest, and further comprising:
a measurement chamber of known volume;
an opening proximate a distal end of the cannula;
a plunger sized and configured for introducing a negative pressure in the measurement chamber when retracted for withdrawing fluid from the blood vessel of interest through the opening into the measurement chamber; and
a radiation detector positioned proximate the measurement chamber-for detecting radiation emitted from the fluid withdrawn into the measurement chamber.
2 . The device of claim 1 wherein the radiation detector comprises scintillation material that emits light when impacted with particles emitted from a radioactive material, wherein at least a portion of the light is received by an optical connector.
3 . The device of claim 2 , wherein the cannula further comprises a fiber optic material.
4 . The device of claim 3 , wherein the at least a portion of the light propagates via the fiber optic material to the optical connector.
5 . The device of claim 3 , wherein the scintillation material is shaped to focus light to at least one of the fiber optic material and the optical connector.
6 . The device of claim 2 , wherein the optical connector comprises an optical detector, and further wherein the optical detector converts the received light into an electrical signal for processing.
7 . The device of claim 1 , wherein the cannula comprises needle material.
8 . The device of claim 7 wherein the needle material is operatively removable from the cannula after the cannula is positioned within the blood vessel of interest.
9 . The device of claim 1 , wherein the plunger is translated to re-insert the withdrawn fluid to the blood vessel of interest.
10 . The device of claim 1 further comprising a particle absorption material substantially surrounding the measurement chamber and the radiation detector for shielding the radiation detector from radiation emitted from sources outside the measurement chamber.
11 . The device of claim 10 wherein the particle absorption material comprises a metal.
12 . The device of claim 1 wherein the radiation detector extends about a full circumference of the measurement chamber.
13 . A method of measuring levels of radiotracers in a blood vessel of interest, the method comprising;
a. inserting a cannula into a blood vessel of interest, wherein the cannula comprises a measurement chamber of known volume, an opening proximate a distal end of the cannula, and a plunger sized and configured for introducing a negative pressure in the measurement chamber when retracted for withdrawing fluid from the blood vessel of interest through the opening into the measurement chamber;
b. retracting the plunger to introduce the negative pressure in the measurement chamber such that fluid from the blood vessel of interest is withdrawn into the measurement chamber; and
c. utilizing a radiation detector, measuring radiation emitted from the within the measurement chamber.
14 . The method of claim 13 wherein the radiation detector comprises scintillation material that emits light when impacted with particles emitted from a radioactive material, and the measurement of radiation emitted from fluid within the measurement chamber is determined using the emitted light.
15 . The method of claim 14 wherein at least a portion of the emitted light is transmitted from the radiation detector via a fiber optic material to an optical detector for converting the received light into an electrical signal for processing.
16 . The method of claim 13 wherein the cannula comprises needle material.
17 . The method of claim 16 wherein the needle material is operatively removable from the cannula after the cannula is positioned within the blood vessel of interest.
18 . The method of claim 13 wherein a particle absorption material substantially surrounds the measurement chamber and the radiation detector to shield the radiation detector from radiation emitted from sources outside the measurement chamber.
19 . The method of claim 13 further comprising unretracting the plunger to remove the negative pressure in the measurement chamber such that the withdrawn fluid is returned to the blood vessel of interest.