Obviousness

Obviousness Analysis of US11369322 under 35 U.S.C. § 103

The patent US11369322, titled "Methods and systems for retrospective internal gating," claims a method, a computer-readable medium, and a system for correcting for motion in acquired image data. The effective prior art date for US11369322 is May 4, 2007, based on its priority claim to U.S. Provisional Patent Application 60/916,200, filed on that date.

The independent claims (Claims 1, 19, and 20) essentially describe a process involving:

1. Acquiring image data over time (t1...tn) for a moving object.
2. Extracting information from multiple arrays (e.g., voxels) derived from this image data.
3. Generating a time-varying object motion function based on this extracted information.
4. Determining phase information for the object's motion from the motion function.
5. Generating a motion-corrected image using the phase information and acquired data.

The core of the invention lies in using "retrospective internal gating" where motion information is derived from "individual voxel signal fluctuations" within the image data itself, rather than external hardware.

A person having ordinary skill in the art (PHOSITA) in medical imaging, as of May 4, 2007, would have been motivated to combine existing prior art references to arrive at the claimed invention, particularly given the known advantages of software-derived, image-based motion correction. The patent itself highlights that "Acquiring and using software derived respiratory signals have several advantages over hardware based methods. The algorithms are image based, and thus machine independent, and can be used with existing scans, or scanners."

For an obviousness analysis, the following prior art references, cited by US11369322 and having priority dates before May 4, 2007, are particularly relevant:

• US7359535B2 (Priority: 2003-06-20, Publication: 2008-04-15) titled "Systems and methods for retrospective internal gating."
• US20050123183A1 (Priority: 2003-09-02, Publication: 2005-06-09) titled "Data driven motion correction for nuclear imaging."
• US20080253636A1 (Priority: 2007-04-11, Publication: 2008-10-16) titled "Respiratory motion extraction from tomographic projection and image data."

Obviousness Argument for Claim 1

1. Acquiring image data corresponding to times t1...tn to be used to generate one or more images corresponding to a moving object:
This step is fundamental to virtually all medical imaging techniques, including CT, PET, and MRI, as acknowledged by the patent itself. Prior art such as US7359535B2 ("Systems and methods for retrospective internal gating"), US20050123183A1 ("Data driven motion correction for nuclear imaging"), US6144874A ("Respiratory gating method for MR imaging"), and US6298260B1 ("Respiration responsive gating means and apparatus and methods using the same") all inherently teach the acquisition of image data for a moving object for subsequent processing or correction.

2. Extracting information for a plurality of arrays derived from the image data:
The patent describes "arrays" as individual voxels or regions of interest within the image data, with "information" being their time-activity values. A PHOSITA, seeking to perform "data driven motion correction" as taught by US20050123183A1, would naturally look to the raw image data itself (e.g., pixel or voxel values) as the source of this "data." Furthermore, US20080253636A1 explicitly teaches "Respiratory motion extraction from tomographic projection and image data," directly supporting the concept of extracting motion-related information from the acquired image data.

3. Generating a time varying object motion function based on the extracted information for the plurality of arrays of the image data:
The concept of generating a function that characterizes motion from internal data was known. US20050123183A1, with its "Data driven motion correction," strongly implies deriving such a motion function directly from the acquired image data. US20080253636A1 further specifies "Respiratory motion extraction from tomographic projection and image data," which is precisely the generation of a time-varying function of respiratory motion from image data elements (arrays/voxels). The patent itself mentions that "software based methods have been proposed which utilize characterization of structural movement to gate the scans."

4. Determining, based on the time varying object motion function, phase information for motion of the moving object:
Once a time-varying object motion function is generated, determining phase information (e.g., identifying peaks and troughs corresponding to different phases of a respiratory cycle) is a standard practice in medical imaging, particularly for gating applications. Patents like US7359535B2 ("retrospective internal gating"), US6144874A ("Respiratory gating method for MR imaging"), and US6298260B1 ("Respiration responsive gating means and apparatus and methods using the same") would all require and teach the determination of motion phase information for their gating functionalities.

5. Generating at least one image correcting for the motion of the moving object based on the determined phase information for motion of the moving object and the acquired image data:
The ultimate goal of gating is to produce motion-corrected images. The patent explains that "Respiratory gating in is an approach to lessen the image degradation from respiratory motion by separating the breathing cycle into different phases and generating images from data corresponding to each of these phases." Therefore, using the determined phase information to reconstruct motion-corrected images is a direct and obvious consequence of any gating process, as taught by US7359535B2 and other gating references.

Motivation to Combine

A PHOSITA would be motivated to combine the teachings of US7359535B2, US20050123183A1, and US20080253636A1 to arrive at the invention of US11369322 for the following reasons:

1. Addressing a Known Problem: Patient motion during image acquisition was a widely recognized problem causing image degradation and blurring. Respiratory gating was a known solution.
2. Desire for Software-Based Solutions: The advantages of "software derived respiratory signals" over hardware-based methods (machine independence, use with existing scans, automation, temporal alignment) were well-understood and desired in the art.
3. Combination of Retrospective Internal Gating with Data-Driven Extraction:
   • US7359535B2 explicitly teaches "retrospective internal gating," providing the overarching goal of deriving motion information internally from the patient (without external sensors) and applying it retrospectively.
   • US20050123183A1 teaches "data driven motion correction" in nuclear imaging, suggesting that motion information should be extracted directly from the acquired image data itself.
   • US20080253636A1 provides a specific method for "Respiratory motion extraction from tomographic projection and image data," demonstrating how to derive the specific type of motion (respiratory) from the source data (tomographic projection/image data).

A PHOSITA seeking to implement the "internal" aspect of "retrospective internal gating" (US7359535B2) in a software-based manner would naturally look to "data driven" methods (US20050123183A1) that extract motion information directly from image data (US20080253636A1). It would be obvious to use the fluctuations of individual voxel signals (arrays) within the image data as the source for this "data driven" respiratory motion extraction to generate the time-varying object motion function required for retrospective gating. The subsequent steps of determining phase information and generating a corrected image are inherent to any gating process once the motion function is established.

Therefore, the combination of these prior art references would render Claim 1, and by extension the functionally identical Claims 19 and 20, obvious to a PHOSITA as of the priority date of US11369322.