Reconstructing time-varying position of individual radioactive cells directly from positron emission tomography (PET) measurements

Patent metadata

Field	Value
Publication number	US-9962136-B2
Application number	US-201514711396-A
Country	US
Kind code	B2
Filing date	May 13, 2015
Priority date	Jun 4, 2014
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A method of reconstructing time-varying position of individual radioactive point sources directly from Positron Emission Tomography (PET) measurements is provided that includes using a PET scanner to acquire list-mode coincidence events of a moving radioactive point source, using an appropriately programmed computer to model a trajectory of the moving radioactive point source as a 3D function of a temporal variable, then apply an optimization procedure to find the trajectory that minimizes a distance between the trajectory and the recorded list-mode coincidence events, and using the PET scanner to output a real time position of the radioactive point source.

First claim

What is claimed:

1. A method of reconstructing time-varying positions of an individual radioactive cell, comprising:
a. transplanting to a human or animal host a radioactive cell;
b. acquiring a positron emission tomography (PET) scan, using a PET scanner, of said human or said animal host to obtain a list of coincidence events containing lines and corresponding timestamps;
c. using a computer to:
i. model a time-varying position of said radioactive cell as a 3D function of a temporal variable;
ii. determining an average distance for different parameters of said 3D function, wherein said average distance is determined by computing a geometrical distance between one said line in said list of coincidence events and a 3D position given by said 3D function for said timestamp corresponding to said one line, wherein an average of all said computed geometrical distances is computed;
iii. iteratively repeating said modeling step i) and said average distance determination of step ii) until said average distance converges to a minimum distance; and

d. reconstructing a time-varying position of said radioactive transplanted cell, using said PET scanner, by outputting said 3D function of said temporal variable of said reconstructed time-varying position of said transplanted radioactive cell, wherein said reconstructed time-varying position provides an estimate of individual cell migration in real time inside said human or animal host.

2. The method of claim 1 , wherein said 3D function comprises a B-spline function of said temporal variable.

3. The method according to claim 1 , wherein a regularization term is added to said geometrical distance to favor desirable trajectories over undesirable trajectories, wherein if no said list of coincidence events are detected over a pre-defined time interval, a shortest trajectory is selected from available said list of coincidence events.

4. The method of claim 1 , wherein said geometrical distance comprises a mean-square distance.

5. The method according to claim 1 , wherein said computing a geometrical distance comprises assigning a constant value to events that have a geometrical distance greater than a predefined distance d max .

Assignees

• Univ Leland Stanford Junior

Inventors

• Pratx Guillem

Classifications

• A61B6/037

  Emission tomography · CPC title

• A61B6/508

  for non-human patients · CPC title

• A61B6/486

  involving generating temporal series of image data · CPC title

• A61B6/5264 Primary

  due to motion · CPC title