US 10117625

US patent 10117625, titled "Methods and systems for retrospective internal gating," was issued to Memorial Sloan Kettering Cancer Center.

Here's a concise summary:

• Title: Methods and systems for retrospective internal gating
• Assignee: Memorial Sloan Kettering Cancer Center
• Inventors: Adam L. Kesner
• Filing Date: October 9, 2017
• Issue Date: November 6, 2018
• Abstract: The patent describes a method for deriving respiratory gated PET image reconstruction from raw PET data. It uses respiratory motion information derived from individual voxel signal fluctuations, combined to create usable respiratory phase information. This approach enables the reconstruction of respiratory gated PET images without external hardware and in a fully automated manner.

Independent Claims Overview:

• Claim 1 (Method): This claim describes a method for retrospective internal gating involving several steps:

  1. Acquiring a series of images over time (t1...tn) that include a moving object.
  2. Extracting time-activity information for individual voxels within these images.
  3. Generating a time-varying object motion function based on this extracted time-activity information.
  4. Using the generated motion function to determine phase information for the moving object's motion.
  5. Generating an updated series of images that correct for the object's motion using the determined phase information.

• Claim 19 (Non-transitory computer-readable medium): This claim covers a non-transitory computer-readable medium encoded with a program. When executed by one or more processors, the program causes a machine to perform the same five steps as outlined in independent Claim 1 (acquiring images, extracting time-activity, generating motion function, determining phase information, and generating corrected images).

• Claim 20 (System): This claim describes a system comprising one or more processors and a non-transitory computer-readable medium. This medium stores instructions that, when executed by the processors, cause the system to perform the identical five steps described in independent Claim 1 (acquiring images, extracting time-activity, generating motion function, determining phase information, and generating corrected images).

Regarding CAFC 2026 dockets, no results were found for US patent 10117625 for the year 2026. This indicates that there are no publicly available records of litigation involving this specific patent in the Court of Appeals for the Federal Circuit for the specified period.

As of April 26, 2026, there is no known litigation involving US patent 10117625. Searches of public litigation databases, including those for the CAFC and PACER, and Unified Patents, did not yield any results for this specific patent number.

Proceedings overview

As of the current date, there are no publicly available records of any AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method review) filed against US patent 10117625 with the USPTO's Patent Trial and Appeal Board (PTAB). The USPTO ODP API returns no AIA trial proceedings for this patent, and web searches did not surface any older or recently-filed proceedings. This indicates that the patent, US10117625, has not been challenged through the AIA trial processes. This gives a defendant facing assertion of this patent a completely open defensive posture, as no claims have been invalidated or sustained by the PTAB, and all prior art grounds remain available for challenge.

Strategic summary

Since there is no PTAB activity on file for US10117625, all claims (1-20) remain untested by the PTAB. There are no canceled or sustained claims through an AIA trial proceeding.

The estoppel landscape is entirely open. Since no IPRs have been filed, Section 315(e)(2) estoppel does not apply to any potential petitioner or their privies. This means that any defendant currently being asserted against can raise any available prior-art grounds, including those that could have been raised in an IPR, without being barred by previous PTAB decisions.

There are no patterns of filings by a specific petitioner, no aggressive pursuit of PTAB appeals by the patent owner, and no involvement of defensive aggregators like Unified Patents, as there are simply no PTAB proceedings to observe for this patent.

Recommended next steps

If you are a defendant facing assertion of US10117625, the absence of PTAB activity is a significant signal. It suggests that the patent has not yet undergone the scrutiny of an AIA trial. Your recommended next steps would be:

• Consider filing your own AIA trial petition: Given the absence of prior PTAB challenges, you have a clear path to challenge the patentability of the claims based on prior art under Sections 102 (novelty) and/or 103 (obviousness). This could be an Inter Partes Review (IPR) for patentability challenges based on patents or printed publications.
• Conduct a thorough prior art search: Since no prior art has been adjudicated by the PTAB against this patent, a comprehensive search for patents and printed publications that anticipate or render obvious the claims of US10117625 is crucial.
• Evaluate claims individually: Analyze each claim of US10117625 to identify potential weaknesses in light of the prior art and to formulate strong invalidity arguments.
• Monitor for future PTAB filings: While no proceedings are currently active, it is advisable to regularly check the USPTO's Patent Trial and Appeal Case Tracking System (P-TACTS) (https://search.uspto.gov/ptacts/) for any newly filed petitions against this patent, as the landscape can change rapidly.

Inventors

• Adam L. Kesner (Memorial Sloan Kettering Cancer Center at the time of filing)

Original assignee

The entity named on the issued patent is Memorial Sloan Kettering Cancer Center. They are a prominent medical institution engaged in cancer treatment, research, and education. While they may not "ship a product" in the traditional commercial sense, they utilize and implement advanced medical imaging methods and systems, including those related to retrospective internal gating, in their clinical and research operations. Memorial Sloan Kettering Cancer Center is currently operating and is a well-known active medical center.

Assignment timeline

• 2017-05-30 (executed) / recorded 2024-05-30 — Reel 067574/0953
  • Conveyance: Assignment of Assignors Interest
  • Assignor: KESNER, ADAM
  • Assignee: MEMORIAL SLOAN KETTERING CANCER CENTER
  • Correspondent: BAKER & MCKENZIE LLP
  • Context: Inventor assignment to original assignee.

Timeline diagram

timeline
    title Ownership of US 10117625
    2017 : Filed by Memorial Sloan Kettering
         : Inventor assigned to MSKCC
    2018 : Issued
    2024 : Inventor assignment recorded

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The only recorded transfer is from the inventor to Memorial Sloan Kettering Cancer Center, a well-known operating medical institution.
2. Known asserter in the chain — Not present. Memorial Sloan Kettering Cancer Center is not on any public NPE list.
3. Repeat correspondent across the chain — Unclear. There is only one recorded assignment, with BAKER & MCKENZIE LLP as the correspondent (Reel 067574/0953). There is no recurrence within this chain to assess a pattern.
4. Cascading transfers — Not present. Only one assignment is recorded.
5. Pre-litigation transfer — Not present. No litigation for US10117625 was found for 2026 (as per the prior analysis), and the recorded assignment from the inventor to the original assignee was executed prior to the patent's filing date.
6. Bankruptcy fire-sale — Not present. Memorial Sloan Kettering Cancer Center is a currently operating institution and has not filed for bankruptcy.
7. Privateering — Not present. There is no indication of an operating company transferring the patent to an NPE for assertion.
8. Defensive aggregator (anti-NPE) — Not present. The patent is currently assigned to Memorial Sloan Kettering Cancer Center, not a defensive aggregator.

Verdict

Insufficient data. There is only one recorded assignment for US10117625 (Reel 067574/0953), which is the inventor, Adam Kesner, assigning their interest to Memorial Sloan Kettering Cancer Center. This transfer was executed before the patent's filing date and recorded in 2024. This record does not provide any signals to indicate an NPE pattern, suggesting the patent remains with the original operating assignee.

USPTO Assignment Center search for US10117625: https://assignmentcenter.uspto.gov/

Here is an analysis of the patent citations listed in US patent 10117625, identifying potentially relevant prior art under 35 U.S.C. § 102. The focus is on patents whose titles suggest a connection to motion correction, gating, or image processing for medical imaging.

Most Relevant Prior Art for US10117625

The following patents are cited in US10117625 and appear to be highly relevant due to their focus on motion correction, gating, or related image processing techniques.

1. US6298260B1

   • Full Citation: US6298260B1, "Respiration responsive gating means and apparatus and methods using the same," issued to St. Jude Children's Research Hospital.
   • Publication/Filing Date: Publication date: 2001-10-02; Priority date: 1998-02-25.
   • Brief Description: This patent describes means, apparatus, and methods for respiratory responsive gating.
   • Potential Anticipation: This patent potentially anticipates aspects of Claims 1, 19, and 20 relating to the general concept of "gating" in response to physiological motion, specifically respiration, and the methods/systems for achieving it. While US10117625 emphasizes "retrospective internal gating" using voxel time-activity, this prior art establishes the broader concept of respiratory gating.

2. US6144874A

   • Full Citation: US6144874A, "Respiratory gating method for MR imaging," issued to General Electric Company.
   • Publication/Filing Date: Publication date: 2000-11-07; Priority date: 1998-10-15.
   • Brief Description: This patent details a method for respiratory gating specifically for Magnetic Resonance (MR) imaging.
   • Potential Anticipation: This citation directly addresses "respiratory gating method," which is a core application of US10117625. It potentially anticipates the general methodological steps of respiratory gating and acquiring images (Claim 1), and by extension, the computer-readable medium (Claim 19) and system (Claim 20) configured to perform such a method, particularly within the context of medical imaging where MR is a common modality.

3. US6539074B1

   • Full Citation: US6539074B1, "Reconstruction of multislice tomographic images from four-dimensional data," issued to General Electric Company.
   • Publication/Filing Date: Publication date: 2003-03-25; Priority date: 2000-08-25.
   • Brief Description: This patent concerns the reconstruction of multislice tomographic images using four-dimensional data, which often implies a temporal dimension to account for motion.
   • Potential Anticipation: The concept of using "four-dimensional data" (which includes time) for image reconstruction to address motion is relevant. It could potentially anticipate aspects of Claim 1 related to processing a series of images over time (t1...tn) and generating updated images, particularly if the "four-dimensional data" implicitly or explicitly incorporates motion phase information, and thus, Claims 19 and 20 by extension.

4. US20050123183A1

   • Full Citation: US20050123183A1, "Data driven motion correction for nuclear imaging," issued to Paul Schleyer.
   • Publication/Filing Date: Publication date: 2005-06-09; Priority date: 2003-09-02.
   • Brief Description: This publication describes methods for "data driven motion correction" specifically for "nuclear imaging."
   • Potential Anticipation: This is highly relevant as US10117625 specifically mentions PET (a nuclear imaging modality) and emphasizes "software derived respiratory signals" or "image based methods." The title "Data driven motion correction" directly aligns with the internal gating approach of US10117625, which uses extracted image data (voxel time-activity) to generate a motion function. This citation potentially anticipates Claims 1, 19, and 20, especially regarding using image data for motion correction without external hardware.

5. US7359535B2

   • Full Citation: US7359535B2, "Systems and methods for retrospective internal gating," issued to Ge Medical Systems Global Technology Company, Llc.
   • Publication/Filing Date: Publication date: 2008-04-15; Priority date: 2003-06-20.
   • Brief Description: This patent shares the exact title "Systems and methods for retrospective internal gating" with US10117625.
   • Potential Anticipation: Given the identical title, this patent is critically relevant and likely anticipates fundamental aspects of Claims 1, 19, and 20. It would likely teach the core concepts of acquiring images, extracting internal motion signals, determining phase information, and generating corrected images retrospectively. The differentiation for US10117625 would lie in the specific mechanism of internal signal extraction (e.g., individual voxel time-activity information) and the method of generating the time-varying object motion function, which would need careful comparison.

6. US7574249B2

   • Full Citation: US7574249B2, "Device-less gating of physiological movement for improved image detection," issued to General Electric Company.
   • Publication/Filing Date: Publication date: 2009-08-11; Priority date: 2005-02-08.
   • Brief Description: This patent describes a method for "device-less gating of physiological movement" to improve image detection.
   • Potential Anticipation: The term "device-less gating" strongly aligns with the "retrospective internal gating" and "software derived respiratory signals" aspects of US10117625, which aims to avoid external hardware. This directly addresses a key advantage highlighted in the description of US10117625. Therefore, it potentially anticipates aspects of Claims 1, 19, and 20 related to motion gating without external sensors, particularly for physiological movements.

7. US20080253636A1

   • Full Citation: US20080253636A1, "Respiratory motion extraction from tomographic projection and image data," issued to Deller Timothy W.
   • Publication/Filing Date: Publication date: 2008-10-16; Priority date: 2007-04-11.
   • Brief Description: This publication focuses on extracting respiratory motion from "tomographic projection and image data."
   • Potential Anticipation: This is highly relevant as it explicitly mentions extracting respiratory motion from image data, which is a core step in US10117625's method of generating a time-varying object motion function from voxel time-activity information. It potentially anticipates the steps of extracting time-activity information for voxels and generating a motion function (Claim 1), and thus the corresponding computer-readable medium (Claim 19) and system (Claim 20).

8. US9814431B2

   • Full Citation: US9814431B2, "Methods and systems for retrospective internal gating," issued to Memorial Sloan Kettering Cancer Center.
   • Publication/Filing Date: Publication date: 2017-11-14; Priority date: 2007-05-04.
   • Brief Description: This patent shares the identical title "Methods and systems for retrospective internal gating" and the same assignee and priority date as US10117625.
   • Potential Anticipation: This is a key reference. Given it shares the same priority date and assignee, it is likely a parent or related application within the same patent family. Therefore, it directly covers the fundamental inventive concept. It is not "prior art" in the traditional sense for anticipation under 35 U.S.C. § 102 if it's part of the same inventive entity and priority chain, but it is certainly the most relevant document outlining the same invention. It would describe the core method of retrospective internal gating, including acquiring images, extracting voxel time-activity information, generating a time-varying object motion function, determining phase information, and generating corrected images, thereby covering all claims (1, 19, 20) of US10117625.

Other Cited Patents

The following cited patents are also relevant to medical imaging and motion correction, though their titles may not indicate as direct a connection to the specific "retrospective internal gating" using voxel time-activity as those listed above.

1. US6556695B1

   • Full Citation: US6556695B1, "Method for producing high resolution real-time images, of structure and function during medical procedures," issued to Mayo Foundation For Medical Education And Research.
   • Publication/Filing Date: Publication date: 2003-04-29; Priority date: 1999-02-05.
   • Brief Description: This patent describes a method for producing high-resolution, real-time images, which often involves addressing motion.
   • Potential Anticipation: Potentially anticipates aspects of image acquisition and the general goal of improving image quality by addressing factors that degrade resolution, which can include motion.

2. US6501981B1

   • Full Citation: US6501981B1, "Apparatus and method for compensating for respiratory and patient motions during treatment," issued to Accuray, Inc.
   • Publication/Filing Date: Publication date: 2002-12-31; Priority date: 1999-03-16.
   • Brief Description: This patent describes an apparatus and method for compensating for respiratory and patient motions, particularly during treatment.
   • Potential Anticipation: Directly relates to compensating for respiratory and patient motion, which is the problem US10117625 seeks to solve. It potentially anticipates the broad concept of motion correction in medical imaging and could overlap with the "generating an updated series of images correcting for the motion" step in Claim 1.

3. US20040218794A1

   • Full Citation: US20040218794A1, "Method for processing perfusion images," issued to Yi-Hsuan Kao.
   • Publication/Filing Date: Publication date: 2004-11-04; Priority date: 2003-05-01.
   • Brief Description: This publication concerns a method for processing perfusion images.
   • Potential Anticipation: While not explicitly mentioning motion gating, image processing methods can sometimes include motion correction. It might anticipate general image processing steps but without further detail, it's difficult to ascertain specific anticipation of US10117625's claims.

4. US7734078B2

   • Full Citation: US7734078B2, "System and method for generating composite substraction images for magnetic resonance imaging," issued to Cornell Research Foundation, Inc.
   • Publication/Filing Date: Publication date: 2010-06-08; Priority date: 2002-09-18.
   • Brief Description: This patent describes a system and method for generating composite subtraction images for MRI.
   • Potential Anticipation: Subtraction imaging can sometimes be used to highlight changes or motion, but the direct relevance to "retrospective internal gating" based on voxel time-activity is not immediately clear from the title.

5. US7756307B2

   • Full Citation: US7756307B2, "Method of, and software for, conducting motion correction for a tomographic scanner," issued to Hammersmith Imanet Limited.
   • Publication/Filing Date: Publication date: 2010-07-13; Priority date: 2003-10-17.
   • Brief Description: This patent describes a method and software for motion correction in a tomographic scanner.
   • Potential Anticipation: The general concept of "motion correction for a tomographic scanner" is relevant to US10117625, especially given that PET and CT are tomographic imaging modalities. It could anticipate the broad idea of a method (Claim 1) and software (Claim 19) for motion correction.

6. US20070081704A1

   • Full Citation: US20070081704A1, "System, program product, and methods for attenuation correction of emission data on PET/CT and SPECT/CT," issued to The University Of Texas System.
   • Publication/Filing Date: Publication date: 2007-04-12; Priority date: 2005-03-17.
   • Brief Description: This publication relates to attenuation correction, specifically for PET/CT and SPECT/CT systems.
   • Potential Anticipation: While related to PET imaging, the primary focus is on attenuation correction rather than motion gating or object motion function generation. It might have indirect relevance if motion impacts attenuation correction.

7. US20070127797A1

   • Full Citation: US20070127797A1, "Methods and systems to facilitate reducing banding artifacts in images," issued to General Electric Company.
   • Publication/Filing Date: Publication date: 2007-06-07; Priority date: 2005-11-23.
   • Brief Description: This publication describes methods and systems for reducing banding artifacts in images.
   • Potential Anticipation: Image artifacts can be caused by motion, so this could be indirectly relevant. However, it doesn't directly address gating or motion function generation.

8. US20070237372A1

   • Full Citation: US20070237372A1, "Cross-time and cross-modality inspection for medical image diagnosis," issued to Shoupu Chen.
   • Publication/Filing Date: Publication date: 2007-10-11; Priority date: 2005-12-29.
   • Brief Description: This publication relates to cross-time and cross-modality inspection for medical image diagnosis.
   • Potential Anticipation: "Cross-time" aspects might involve sequences of images, but without more detail on how motion is handled, direct anticipation of US10117625's specific gating method is not clear.

9. US20080226149A1

   • Full Citation: US20080226149A1, "Motion Compensation in Functional Imaging," issued to Hans-Aloys Wischmann.
   • Publication/Filing Date: Publication date: 2008-09-18; Priority date: 2005-08-04.
   • Brief Description: This publication describes motion compensation in functional imaging.
   • Potential Anticipation: Directly relevant to "motion compensation," which is the ultimate goal of US10117625. It could anticipate the general methodology of correcting for motion in functional imaging (Claim 1) and the associated system and computer-readable medium (Claims 19, 20).

10. US20090290774A1

    • Full Citation: US20090290774A1, "Dynamic computed tomography imaging," issued to Koninklijke Philips Electronics N. V.
    • Publication/Filing Date: Publication date: 2009-11-26; Priority date: 2006-05-26.
    • Brief Description: This publication relates to dynamic computed tomography imaging.
    • Potential Anticipation: "Dynamic CT imaging" often deals with motion. It could anticipate methods for acquiring images over time (Claim 1) and potentially aspects of motion handling, but the specific "retrospective internal gating" from voxel data needs closer examination.

11. US20100183206A1

    • Full Citation: US20100183206A1, "Adjusting acquisition protocols for dynamic medical imaging using dynamic models," issued to Koninklijke Philips Electronics N.V.
    • Publication/Filing Date: Publication date: 2010-07-22; Priority date: 2007-06-21.
    • Brief Description: This publication describes adjusting acquisition protocols for dynamic medical imaging using dynamic models.
    • Potential Anticipation: "Dynamic medical imaging" implies handling motion, and "dynamic models" could relate to modeling object motion. This could have some overlap with the general problem addressed by US10117625.

12. US20090076369A1

    • Full Citation: US20090076369A1, "Method For Reducing Motion Artifacts In Highly Constrained Medical Images," issued to Mistretta Charles A.
    • Publication/Filing Date: Publication date: 2009-03-19; Priority date: 2007-09-17.
    • Brief Description: This publication describes a method for reducing motion artifacts in medical images.
    • Potential Anticipation: Directly addresses the problem of motion artifacts, which US10117625 also aims to mitigate through gating. It could potentially anticipate aspects of Claim 1 related to correcting for motion.

13. US20090299184A1

    • Full Citation: US20090299184A1, "Imaging or communications system utilizing multisample apodization and method," issued to Walker William F.
    • Publication/Filing Date: Publication date: 2009-12-03; Priority date: 2008-02-16.
    • Brief Description: This publication relates to imaging or communications systems utilizing multisample apodization.
    • Potential Anticipation: The relevance to retrospective internal gating for motion correction is not immediately evident from the title.

Under 35 U.S.C. § 103, an invention is considered obvious if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (PHOSITA). The analysis requires identifying: 1) the scope and content of the prior art, 2) the differences between the prior art and the claims, 3) the level of ordinary skill in the art, and 4) any secondary considerations of non-obviousness (though none are provided in the prompt for this analysis).

The priority date for US10117625 is May 4, 2007.

Scope and Content of Prior Art

The provided patent text lists several prior art references under "Citations." Among these, US7359535B2, titled "Systems and methods for retrospective internal gating," has a priority date of June 20, 2003, which precedes the priority date of US10117625, making it highly relevant prior art.

US7359535B2: "Systems and methods for retrospective internal gating"

This patent describes a method for retrospective internal gating, particularly useful for correcting motion artifacts in medical imaging. Key teachings include:

• Acquiring images: It teaches "acquiring images at different times t1 . . . tn" to obtain a chronologically ordered image set.
• Identifying temporally cyclical signals: It describes identifying such signals, often related to physiological motion like respiration or cardiac rhythms.
• Extracting time-activity information for voxels: The patent details how "time-activity information is derived by organizing into a single discrete array the values v1 . . . vn of an individual voxel in the successive images i1 . . . in".
• Generating a time varying object motion function: This function is created by combining time-activity information from multiple voxels. The processing can be initiated by defining the function as the filtered time-activity values of the highest priority voxel, and subsequent filtered voxel time-activity values are synthesized into this function. It also describes scenarios for combining voxel data (add, subtract, unchanged) and selecting the one with the highest standard deviation.
• Determining phase information: "Final phase information for the motion of the imaged object can be extracted from the timing of the peaks and dips in the time varying object motion function". Specifically, for respiratory motion, local maxima and minima can correspond to full inspiration and expiration.
• Purpose of Gating: The background section explicitly states 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". The patent also highlights advantages of "software derived respiratory signals" over "hardware based methods".

Analysis of Obviousness

The independent claims of US10117625 are Claim 1 (method), Claim 19 (non-transitory computer-readable medium), and Claim 20 (system).

Obviousness of Claim 1 of US10117625 over US7359535B2

Claim 1 of US10117625 claims:

1. acquiring a series of images at times t1 . . . tn including a moving object;
   • US7359535B2 explicitly teaches "acquiring images at different times t1 . . . tn" to obtain an image set of a patient (a moving object).
2. extracting time-activity information for voxels of the images;
   • US7359535B2 teaches that "time-activity information is derived by organizing into a single discrete array the values v1 . . . vn of an individual voxel in the successive images i1 . . . in".
3. generating a time varying object motion function based on the extracted time-activity information for the voxels of the images;
   • US7359535B2 teaches that "Information is combined from many voxels' time-activity values to create a time varying object motion function". It further describes the process of initializing and synthesizing subsequent voxel time-activity values into this function.
4. determining, using the time varying object motion function, phase information for motion of the moving object;
   • US7359535B2 teaches that "Final phase information for the motion of the imaged object can be extracted from the timing of the peaks and dips in the time varying object motion function".
5. generating an updated series of images correcting for the motion of the moving object using the determined phase information for motion of the moving object.
   • US7359535B2, in its background, defines respiratory gating as 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". A person having ordinary skill in the art would understand that "generating images from data corresponding to each of these phases" is precisely the step of producing motion-corrected images. The term "updated series of images correcting for the motion" is an inherent and expected outcome of applying a gating technique, as described and enabled by US7359535B2.

Motivation to Combine/Modify:
A PHOSITA would be motivated to perform all steps of Claim 1, as US7359535B2 explicitly teaches the entire process of retrospective internal gating up to determining phase information, and clearly states that the purpose of gating is to generate motion-corrected images. The act of using the determined phase information to generate such corrected images is the natural and intended culmination of the gating method, aiming to achieve the "lessen[ing of] image degradation" for which gating is performed. The patent US10117625 itself acknowledges that "the consensus in literature is that the respiratory gating of images presents a feasible solution to the image degradation introduced by respiratory motion." Therefore, a PHOSITA would naturally complete the gating process by generating images corrected for the motion using the derived phase information.

Obviousness of Claims 19 and 20 of US10117625 over US7359535B2

Claims 19 and 20 cover a non-transitory computer-readable medium and a system, respectively, configured to perform the method steps of Claim 1. Given that US7359535B2 teaches a "system and method for retrospective internal gating" and highlights the advantages of "software derived respiratory signals", it would have been obvious to a PHOSITA to implement the disclosed method using a computer system and a computer program. The implementation of algorithms for image processing and reconstruction on computer systems was well-known in the art prior to the priority date of US10117625.

Obviousness of Dependent Claims

All dependent claims of US10117625 are also rendered obvious by US7359535B2:

• Claim 2 (time-activity definition): Explicitly taught by US7359535B2.
• Claims 3-4, 6-7 (weighting factors): US7359535B2 explicitly teaches assigning weighting factors based on mean voxel activity or proximity to spatial activity gradients, and assigning zero weighting factors to unimportant voxels. A PHOSITA would find it obvious to consider signal variation (Claim 6) as another metric for weighting importance.
• Claim 5 (ungated image combination): A common practice in imaging to create a baseline image from time-series data.
• Claims 8-10 (frequency filtering): US7359535B2 explicitly teaches filtering out unwanted frequencies from time-activity signals for respiratory gating. Adjusting frequency windows (Claims 9-10) is a standard optimization technique for filtering.
• Claims 11-13 (serial processing and initial motion function): US7359535B2 teaches prioritizing voxels and initiating the time-varying object motion function with the highest priority voxel's time-activity curve.
• Claim 14 (three scenarios for combining voxel information): Explicitly taught by US7359535B2, including choosing the scenario with the highest standard deviation.
• Claim 15 (determining phase by recurring patterns): Taught by US7359535B2's extraction of phase from peaks and dips in the motion function.
• Claim 16 (mapping image data to phases): This is the functional outcome of gating, as explained in US7359535B2's background.
• Claim 17 (respiratory cycle data): US7359535B2 focuses heavily on respiratory motion.
• Claim 18 (acquiring for more than one breath cycle): Implicit in obtaining "temporally cyclical signals" for physiological motion like respiration over a "series of images".

Conclusion on Obviousness

The method, system, and computer-readable medium claims of US10117625 are rendered obvious by US7359535B2. US7359535B2 teaches all the essential steps of retrospective internal gating using internal voxel time-activity information to derive motion phase information. The final step of generating motion-corrected images, while phrased slightly differently, is the well-understood and explicitly stated purpose of the gating method described in US7359535B2. A PHOSITA would have been motivated to combine these known elements to achieve the recognized benefits of motion correction in medical imaging. Additional prior art such as US20050123183A1 ("Data driven motion correction for nuclear imaging") and US7574249B2 ("Device-less gating of physiological movement") further demonstrate the clear trend and motivation in the field towards data-driven, device-less, retrospective motion correction, reinforcing the obviousness of the claimed invention.