System and method for geometrically-resolved radiographic X-ray imaging
A method of generating a 3D x-ray image cube movie from 2D x-ray images of a patient is provided. The method includes converting first multiple sets of x-ray images of a lung captured at different projection angles into second multiple sets of x-ray images of the lung corresponding to different breathing phases. The method further includes generating a static image cube from each set of the second multiple sets of x-ray images at a respective breathing phase using back projection. The method includes combining the static image cubes corresponding to the different breathing phases of the lung into a 3D x-ray image cube movie through temporal interpolation.
1. A method of generating a 3D x-ray image cube movie from 2D x-ray images of a patient, comprising:
converting multiple first sets of x-ray images of a lung into multiple second sets of x-ray images of the lung, wherein:
each first set of x-ray images includes a plurality of x-ray images captured at different tidal-volume-based breathing phases of the lung and a same projection angle;
each first set of x-ray images of the multiple first sets of x-ray images is captured at a different projection angle from each other first set of x-ray images of the multiple first sets of x-ray images;
each second set of x-ray images includes a plurality of x-ray images captured at a same breathing phase of the lung and different projection angles;
each second set of x-ray images of the multiple second sets of x-ray images is captured at a different breathing phase from each other second set of x-ray images of the multiple second sets of x-ray images; and
the converting includes re-organizing the multiple first sets of x-ray images of the lung by their associated tidal-volume-based breathing phases into the multiple second sets of x-ray images of the lung;
generating a static image cube from each set of the multiple second sets of x-ray images at a respective tidal-volume-based breathing phase using back projection; and
combining the static image cubes corresponding to the different tidal-volume-based breathing phases of the lung into a 3D x-ray image cube movie through temporal interpolation.
2. The method of claim 1 , wherein the x-ray images within any particular set are geometrically resolved and temporally independent.
3. The method of claim 1 , wherein the different tidal-volume-based breathing phases of the lung correspond to different tidal volume percentiles of the lung's movement.
4. The method of claim 1 , wherein the different tidal-volume-based breathing phases of the lung include early exhalation, late exhalation, maximum exhalation, early inhalation, late inhalation, and maximum inhalation of a complete breathing cycle of the patient.
5. The method of claim 1 , wherein one or more sensors are used for measuring biometric signals of the patient as one or more sequences of time series, including one or more of a 3D spatial position localizer, a breathing phase sensor, and a cardiac phase sensor.
6. The method of claim 5 , further comprising:
identifying a cardiac phase gating window using one or more cardiac phase sensor measurements;
predicting a tidal-volume-based breathing phase using one or more breathing phase sensor measurements;
identifying a coincidence between the cardiac phase gating window and the predicted tidal-volume-based breathing phase for generating an x-ray imaging pulse; and
tagging an x-ray image corresponding to the x-ray imaging pulse with the tidal-volume-based breathing phase, the cardiac phase, and 3D spatial position localizer measurements.
7. The method of claim 5 , wherein the 3D spatial position localizer is configured for measuring the patient's real-time body movement caused by respiration and heartbeats and outputting them as time series.
8. The method of claim 5 , wherein the breathing phase sensor is configured for measuring one or more physiologic metrics related to the patient's breathing, including a tidal volume and its first-order time derivative.
9. The method of claim 5 , wherein the cardiac phase sensor is configured for measuring periodic and stationary electrical signal generated by the patient's heart, with characteristic features that correspond to the cardiac phase.
10. The method of claim 5 , wherein two distinct filters are used to remove signal drift and noise from biometric signals of the patient after being synchronized with an x-ray unit's clock.
11. The method of claim 5 , wherein the biometric signals of the patient measured by the one or more sensors are used for triggering an x-ray unit to acquire an x-ray image of the patient at a specific breathing and cardiac phase.
12. The method of claim 11 , wherein:
the x-ray unit includes a clock;
the biometric signals of the patient measured by the one or more sensors are synchronized with the x-ray unit's clock; and
the respective values of the biometric signals are recorded to be associated with the acquired x-ray image.
13. The method of claim 5 , wherein the biometric signals of the patient are measured during a training window before capturing any x-ray image of the patient and the biometric signals of the patient measured during the training window include multiple complete breathing cycles of the patient.
14. The method of claim 13 , wherein multiple tidal volume percentiles within a complete breathing cycle are identified using the biometric signals of the patient measured during the training window, each tidal volume percentile corresponding to one of the different tidal-volume-based breathing phases.
15. The method of claim 13 , wherein the biometric signals of the patient measured during the training window are used for building an optimized breathing prediction model for predicting a desired tidal-volume-based breathing phase at which an x-ray unit is triggered to capture an x-ray image of the patient.
16. The method of claim 15 , wherein the optimized breathing prediction model is based on an autoregressive integrated moving average (ARIMA) model.
17. The method of claim 15 , wherein the desired tidal-volume-based breathing phase for capturing the x-ray image of the patient is configured to coincide with a cardiac gating window during which heart induced lung motion is changing slowly.
18. The method of claim 17 , wherein the cardiac gating window is chosen based on locations of T wave and P wave in an electrocardiogram (ECG) signal such that the heart induced lung motion is changing slowly.
19. The method of claim 1 , wherein the different tidal-volume-based breathing phases of the lung at a particular projection angle are collected from at least two breathing cycles.
20. A system for determining a biophysical model for a lung of a patient from multiple x-ray measurements corresponding to different tidal-volume-based breathing phases of the lung, comprising:
one or more processors; and
memory storing instructions which, when executed by the one or more processors, cause the one or more processors to perform a set of operations, including:
converting multiple first sets of x-ray images of a lung into multiple second sets of x-ray images of the lung, wherein:
each first set of x-ray images includes a plurality of x-ray images captured at different tidal-volume-based breathing phases of the lung and a same projection angle;
each first set of x-ray images of the multiple first sets of x-ray images is captured at a different projection angle from each other first set of x-ray images of the multiple first sets of x-ray images;
each second set of x-ray images includes a plurality of x-ray images captured at a same breathing phase of the lung and different projection angles;
each second set of x-ray images of the multiple second sets of x-ray images is captured at a different breathing phase from each other second set of x-ray images of the multiple second sets of x-ray images; and
the converting includes re-organizing the multiple first sets of x-ray images of the lung by their associated tidal-volume-based breathing phases into the multiple second sets of x-ray images of the lung;
generating a static image cube from each set of the multiple second sets of x-ray images at a respective tidal-volume-based breathing phase using back projection; and
combining the static image cubes corresponding to the different tidal-volume-based breathing phases of the lung into a 3D x-ray image cube movie through temporal interpolation.
21. A non-transitory computer-readable storage medium storing instructions, which, when executed by a system that includes one or more processors, cause the one or more processors to perform a set of operations, including:
converting multiple first sets of x-ray images of a lung into multiple second sets of x-ray images of the lung, wherein:
each first set of x-ray images includes a plurality of x-ray images captured at different tidal-volume-based breathing phases of the lung and a same projection angle;
each first set of x-ray images of the multiple first sets of x-ray images is captured at a different projection angle from each other first set of x-ray images of the multiple first sets of x-ray images;
each second set of x-ray images includes a plurality of x-ray images captured at a same breathing phase of the lung and different projection angles;
each second set of x-ray images of the multiple second sets of x-ray images is captured at a different breathing phase from each other second set of x-ray images of the multiple second sets of x-ray images; and
the converting includes re-organizing the multiple first sets of x-ray images of the lung by their associated tidal-volume-based breathing phases into the multiple second sets of x-ray images of the lung;
generating a static image cube from each set of the multiple second sets of x-ray images at a respective tidal-volume-based breathing phase using back projection; and
combining the static image cubes corresponding to the different tidal-volume-based breathing phases of the lung into a 3D x-ray image cube movie through temporal interpolation.