DETAILED ACTION
Claims 1-20 are pending in this application.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 04/25/2024 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 6-10 and 17 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claims 6-10 and 17 The claims recite focal spots of sizes XS, S, L and XL, however the sizes intended for each are not specified, nor are the focal spot sizes related to one another in a way which clearly indicates intended spot size. Specification paragraph [0066] of the applicant’s specification states that the focal spots range between .4mm to 2 mm in size, so for examination purposes, the examiner is assuming that any pair of focal spots falling in this size range, in which one is larger than the other will be functionally equivalent to having two focal spots of either XS, S, L or XL. The applicant is encouraged to amend to further clarify this limitation.
Claims 3-4 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claims 3 and 4, the claims recite the use of an “air calibration correction value”, however the air calibration correction value generation is introduced in claim 11, from which claims 3 and 4 do not depend. Therefore, it is unclear how a value can be used when its generation has not been disclosed in a prior claim. Appropriate correction is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
3. Claims 1-8 and 11-17 are rejected under 35 U.S.C. 103 as being unpatentable over Zhan (US 20220296202 A1) in view of Stayman (WO 2024072979 A1, Published 04/04/2024).
Regarding claim 1 Zhan discloses; A method for a photon counting computed tomography (PCCT) system, the method comprising:
performing a scan using the PCCT system (Zhan, [0017] the scanning system is a photon-counting CT system, [0015] acquiring a slab scan using the scanning system),
with a first focal spot of a first size (Zhan, [0111] the system has a first focal spot which is incident on a slab, where the first focal spot would inherently have a first focal size);
applying a material decomposition (MD) calibration vector to correct projection data acquired during the scan (Zhan,[0005] material decomposition is performed on projection data generated from the CT scan [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, [0063] the two step material decomposition is applied, the examiner is interpreting this application of material decomposition calibration data to be analogous to applying a MD calibration vector per [0024], [0040] and [0092] of the applicant’s specification, in which material density projection data is generated by applying MD Calibration vectors to projection data, where per [0092] of the applicant’s specification the MD calibration vector is associated with scan parameters),
the material decomposition (MD) calibration vector generated for a second focal spot of a second size (Zhan,[0005] material decomposition is performed on projection data generated from the CT scan to calibrate the CT scanner [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, where [0111]-[0113] the system determines two focal spots, a first focal spot and radiation path, and then a second focal spot which is determined based on scanning the slab and generating calibration data for that radiation path, where in [0121] the calibration radiation paths are determined through material decomposition, therefore the MD data/vectors would be generated for the second focal spot),
[the second size different from the first size;]
reconstructing an image from the corrected projection data (Zhan, [0009] the system used the calibration data to correct the collected X-ray projection data, then an image is reconstructed from this to generate a corrected reconstruction image);
and displaying the image on a display device (Zhan, [0150] – [0151] the CT system is coupled to a computer which generates reconstructed image data and is coupled to a display, therefore the image may be displayed).
Zhan does not teach;
the second size different from the first size;
However, in the same field of endeavor, Stayman teaches;
the second size different from the first size (Stayman, [0008] the system used multiple focal spots, where the spots are a first and a second spot of different sizes, such as one smaller than the other);
The combination of Zhan and Stayman would have been obvious to one of ordinary skill in the art prior to the effective filing date of the presently claimed invention. Zhan teaches a method of photon counting CT calibration and image reconstruction based on generated calibration data, however it does not teach focal spots having different sizes. The motivation to combine the method of Stayman with the method of Zhan lies in that the ability to reconstruct images within multiple focal spots of multiple sizes allows for reconstruction of higher resolution images. (Stayman, [0027])
Regarding claim 2 the combination of Zhan and Stayman teaches; The method of claim 1, further comprising correcting and normalizing the projection data using a first air calibration vector generated for the first focal spot of the first size (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0111]-[0113] where obtaining a first and a second focal spot location with inherently a first and a second size are part of the scan parameters, therefore the air calibration data (air calibration vectors) are generated with the focal spots being taken into account)
and a second air calibration vector generated for the second focal spot of the second size (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0098] multiple air scans and sets of air calibration data may be generated (first and second air calibration vectors respectively) [0111]-[0113] where obtaining a first and a second focal spot location with inherently a first and a second size are part of the scan parameters, therefore the air calibration data (air calibration vectors) are generated with the focal spots being taken into account).
Regarding claim 3 the combination of Zhan and Stayman teaches; The method of claim 2, wherein correcting and normalizing the projection data using the first and second air calibration vectors further comprises (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0111]-[0113] where obtaining a first and a second focal spot location with inherently a first and a second size are part of the scan parameters, therefore the air calibration data (air calibration vectors) are generated with the focal spots being taken into account),
for each energy bin of a total number of energy bins of each detector of the PCCT system, dividing the projection data for the energy bin by the sum of the air calibration correction values of the first air calibration vector for each energy bin of the detector (Zhan, [0058] the system determines a calibration function referred to as the bin weighted response function (Swb ), [0079] and [0080] Swb is determined using equation (7), which takes the estimated calibration values and divides each bin by this value, this is done for each pixel in the slab).
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(Zhan, equation 7, where N is the projection data for each bin and Swb (E’) is the normalized summed air calibration data for the first vector)
Regarding claim 4 the combination of Zhan and Stayman teaches; The method of claim 2, wherein correcting and normalizing the projection data using the first and second air calibration vectors further comprises (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0111]-[0113] where obtaining a first and a second focal spot location with inherently a first and a second size are part of the scan parameters, therefore the air calibration data (air calibration vectors) are generated with the focal spots being taken into account),
for each energy bin of a total number of energy bins of each detector of the PCCT system, dividing the projection data for the energy bin by the air calibration correction value of the first air calibration vector for the energy bin (Zhan, [0058] the system determines a calibration function referred to as the bin weighted response function (Swb ) (correction values) where each value of Swb is a normalized air calibration value for each bin, [0079] and [0080] Swb is determined using equation (7), which takes the estimated calibration values and divides each bin by this value, this is done for each pixel in the slab).
Regarding claim 5 the combination of Zhan and Stayman teaches; The method of claim 2, wherein correcting and normalizing the projection data using the air calibration vector further comprises: for each energy bin of each detector of the PCCT system:
calculating a ratio between a first air calibration correction value of the second air calibration vector for the energy bin normalized by a sum of the air calibration correction values of the second air calibration vector for each energy bin of the detector, and a second air calibration correction value of the first air calibration vector for the energy bin normalized by a sum of the air calibration correction values of the first air calibration vector for each energy bin of the detector (Zhan, [0056] the system generates a forward calibration model (figure (1) of Zhan, shown below), [0057]-[0058] where the model shows that the total air calibration/air flux data is denoted by N0 , this is multiplied by the summed change in the values of the calibration data at each bin (Sb ) (Normalization by the sum of values), the integral is then taken of this function, which is functionally equivalent to a ratio of the first value over the second values normalized by the total flux when the integral is evaluated, this is done for each bin as shown in equation (1), this generates a normalized calibration bin response function Swb (E ));
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(Zhan, [0056]-[0058])
and dividing the corrected projection data for the energy bin by the sum of the air calibration correction values of the first air calibration vector for each energy bin of a relevant detector (Zhan, [0058] the system determines a calibration function referred to as the bin weighted response function (Swb )(Air calibration correction values) where each value of Sb is a normalized air calibration value for each bin, [0079] and [0080] Swb is determined using equation (7), which takes the estimated calibration values and divides each bin by this value, this is done for each pixel in the slab, shown below is the bin projection data (Nb ) which is divided by the summed corrected air calibration data (Swb )),
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(Zhan, equation 7, where N is the projection data for each bin and Swb (E’) is the normalized summed air calibration data)
and then multiplying the result by the ratio to obtain a normalized photon count at the energy bin of the detector (Zhan, [0079] and [0080] and equation 7, Swb (E ) is the ratio of the air vector values is multiplied by the other values of in equation (7) where Nb is the values of the bin data and Swb (E’) is the normalized sum of the calibration data, per [0059] this estimation is used to normalized and calibrate the photon count rates).
Regarding claim 6 the combination of Zhan and Stayman teaches; The method of claim 1, further comprising applying a pile-up calibration vector to correct projection data acquired during the scan (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts, the pile up correction value of Zhan is being interpreted as being functionally equivalent to the pile up calibration vector claimed by the applicant because [0078] of applicant’s specification notes that pile-up calibration vectors are generated from acquiring calibration scans, and in Zhan, the pile-up values are determined from calibration scan data as well),
the pile-up calibration vector generated not dependent on focal spot size (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts, not a dependent on focal spot size).
Regarding claim 7 the combination of Zhan and Stayman teaches; The method of claim 1, wherein the first focal spot of the first size is a large (L) focal spot (Stayman, [0030] the system may use two focal spots, where one or both focal spots may be large or small, alternatively, one spot may be large and one may be small, where in [0039] Stayman notes that spot sizes range from .4mm to 1 mm, applicant notes in [0065] the focal spots have four sizes, XS, S, L and XL, where per [0066] of the applicant’s specification the focal spot size ranges from .3 mm to 2 mm), the actual spot size corresponding to each of the XS, S, L and XL spots are not explicitly disclosed, therefore the examiner is interpreting any focal spot size within the range given as being acceptable, and further the examiner will consider having two focal spots, where one is disclosed as being larger than the other as being analogous to a first spot of size L and a second spot of size XL),
and the second focal spot of the second size is an extra-large (XL) focal spot (Stayman, [0030] the system may use two focal spots, where one or both focal spots may be large or small, alternatively, one spot may be large and one may be small, where in [0039] Stayman notes that spot sizes range from .4mm to 1 mm, applicant notes in [0065] the focal spots have four sizes, XS, S, L and XL, where per [0066] of the applicant’s specification the focal spot size ranges from .3 mm to 2 mm), the actual spot size corresponding to each of the XS, S, L and XL spots are not explicitly disclosed, therefore the examiner is interpreting any focal spot size within the range given as being acceptable, and further the examiner will consider having two focal spots, where one is disclosed as being larger than the other as being analogous to a first spot of size L and a second spot of size XL).
The combination of Zhan and Stayman would have been obvious to one of ordinary skill in the art prior to the effective filing date of the presently claimed invention. The motivation for the combination lies in that Stayman’s teaching of using two different focal spot sizes allows for finer resolution in the resulting captured images (Stayman [0008]-[0010]).
Regarding claim 8 the combination of Zhan and Stayman teaches; The method of claim 1, wherein the first focal spot of the first size is an extra-small (XS) focal spot (Stayman, [0030] the system may use two focal spots, where one or both focal spots may be large or small, alternatively, one spot may be large and one may be small, where in [0039] Stayman notes that spot sizes range from .4mm to 1 mm, applicant notes in [0065] the focal spots have four sizes, XS, S, L and XL, where per [0066] of the applicant’s specification the focal spot size ranges from .3 mm to 2 mm), the actual spot sizes corresponding to each of the XS, S, L and XL spots are not explicitly disclosed, therefore the examiner is interpreting any focal spot size within the range given as being acceptable, and further the examiner will consider that disclosing a system having two focal spots, where one is disclosed as being larger than the other as being analogous to a first spot of size Xs and a second spot of size S),
and the second focal spot of the second size is a small (S) focal spot (Stayman, [0030] the system may use two focal spots, where one or both focal spots may be large or small, alternatively, one spot may be large and one may be small, where in [0039] Stayman notes that spot sizes range from .4mm to 1 mm, applicant notes in [0065] the focal spots have four sizes, XS, S, L and XL, where per [0066] of the applicant’s specification the focal spot size ranges from .3 mm to 2 mm), the actual spot sizes corresponding to each of the XS, S, L and XL spots are not explicitly disclosed, therefore the examiner is interpreting any focal spot size within the range given as being acceptable, and further the examiner will consider that disclosing a system having two focal spots, where one is disclosed as being larger than the other as being analogous to a first spot of size Xs and a second spot of size S).
The combination of Zhan and Stayman would have been obvious to one of ordinary skill in the art prior to the effective filing date of the presently claimed invention. The motivation for the combination lies in that Stayman’s teaching of using two different focal spot sizes allows for finer resolution in the resulting captured images (Stayman [0008]-[0010]).
Regarding claim 11 the combination of Zhan and Stayman; A photon counting computed tomography (PCCT) system, comprising:
an X-ray source that emits a beam of X-rays toward a subject to be imaged (Zhan, [0002] an X-ray source emits radiation to image the subject or object);
a photon counting detector that receives the beam of X-rays attenuated by the subject (Zhan, [0003] the system uses a photon counting detector to receive the radiation which has been attenuated);
a data acquisition system (DAS) operably connected to the detector (Zhan, [0150] a data acquisition system (DAS) is coupled to the detector);
and a computer comprising a processor and a non-transitory memory operably connected to the DAS, wherein instructions are stored in the non-transitory memory that when executed cause the processor to (Zhan, [0151] the system contains a memory and a processing device which are connected to the DAS discloses in [0150]):
during a scan performed using the PCCT system: collect a photon count at each detector of the PCCT system (Zhan, [0006] the system uses a photon counting detector to collect a photon count based on the radiation emitted);
apply a pile-up calibration correction value (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts,),
a tube current calibration correction value (Zhan, [0009] a tube angle is computed to be used in calibration/correction, which is being interpreted as being analogous to a tube current calibration correction value),
an air calibration correction value (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data),
and a material decomposition (MD) calibration correction value to the photon count to obtain one or more material decomposed sinograms (Zhan, [0019] the generated calibration data (MD calibration correction values/vectors) is used to obtain sinogram data from the photon counting CT data);
reconstruct an image based on the one or more material decomposed sinograms (Zhan, [0020] the sinogram data is used to generate a reconstructed image),
and output the image to a display device (Zhan, [0150] – [0151] the CT system is coupled to a computer which generates reconstructed image data and is coupled to a display, therefore the image may be displayed);
wherein the air calibration correction value and the tube current calibration correction value are based on a first focal spot size used during the scan (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0111]-[0113] where obtaining a first and a second focal spot location with inherently a first and a second size are part of the scan parameters, therefore the air calibration data (air calibration vectors) are generated with the focal spot being taken into account),
and the MD calibration correction value is based on a second focal spot size not used during the scan (Zhan,[0005] material decomposition is performed on projection data generated from the CT scan to calibrate the CT scanner [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, where [0111]-[0113] the system determines two focal spots, a first focal spot and radiation path, and then a second focal spot which is determined based on scanning the slab and generating calibration data for that radiation path, where in [0121] the calibration radiation paths are determined through material decomposition, therefore the MD data/vectors would be generated for the second focal spot, where the second focal spot is not used in the scan, it is a calibration spot),
the second focal spot size different from the first focal spot size (Stayman, [0008] the system used multiple focal spots, where the spots are a first and a second spot of different sizes, such as one smaller than the other).
The combination of Zhan and Stayman would have been obvious to one of ordinary skill in the art prior to the effective filing date of the presently claimed invention. Zhan teaches a method of photon counting CT calibration and image reconstruction based on generated calibration data, however it does not teach focal spots having different sizes. The motivation to combine the method of Stayman with the method of Zhan lies in that the ability to reconstruct images within multiple focal spots of multiple sizes allows for reconstruction of higher resolution images. (Stayman, [0027])
Regarding claim 12 the combination of Zhan and Stayman teaches; The PCCT system of claim 11, wherein the pile-up calibration correction value, the tube current calibration correction value, the air calibration correction value, and the MD calibration correction value are retrieved from a pile-up calibration vector, a first air calibration vector, a tube current calibration vector, and an MD calibration vector, respectively, stored in the non-transitory memory (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts, [0009] a tube angle is computed to be used in calibration/correction, which is being interpreted as being analogous to a tube current calibration correction value, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0005] material decomposition is performed on projection data generated from the CT scan to calibrate the CT scanner [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, where as per the calibration calculations described in [0070]-[0080] of Zhan, the system uses matrices of vectors to store the data).
Regarding claim 13 the combination of Zhan and Stayman teaches; The PCCT system of claim 12, wherein at each detector, the pile-up calibration correction value, the tube current calibration correction value, the air calibration correction value, and the MD calibration correction value are applied to generate a material decomposed sinogram (Zhan, [0020] the sinogram data is used to generate a reconstructed image, [0009] all calibration data (includes, pileup correction, tube current calibration, air calibration and MD calibration) are used to generate the sinogram data).
Regarding claim 14 the combination of Zhan and Stayman teaches; The PCCT system of claim 13, wherein the photon count at each energy bin is normalized by a sum of air calibration correction values across all energy bins of the detector (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data for all energy bins of the detector, [0058] the system determines a calibration function referred to as the bin weighted response function (Swb ), [0079] and [0080] Swb is determined using equation (7), which takes the estimated calibration values and divides each bin by this value, this is done for each pixel in the slab).
Regarding claim 15 the combination of Zhan and Stayman teaches; The PCCT system of claim 13, wherein the photon count at each energy bin is normalized by the air calibration correction value applied at the energy bin (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data for all energy bins of the detector, [0058] the system determines a calibration function referred to as the bin weighted response function (Swb ), [0079] and [0080] Swb is determined using equation (7), which takes the estimated calibration values and divides each bin by this value, this is done for each pixel in the slab) .
Regarding claim 16 the combination of Zhan and Stayman teaches; The PCCT system of claim 13, wherein further instructions are stored in the non-transitory memory that when executed, cause the processor to (Zhan, [0151] the system contains a memory and a processing device which are connected to the DAS discloses in [0150]):
retrieve a second air calibration vector from the non-transitory memory, the second air calibration vector generated for the second focal spot size (Zhan, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0111]-[0113] where obtaining a first and a second focal spot location with inherently a first and a second size are part of the scan parameters, therefore the air calibration data (air calibration vectors) are generated with the focal spots being taken into account);
and at each energy bin of each detector of the PCCT system: calculate a ratio between a first air calibration correction value of the second air calibration vector for the energy bin normalized by a sum of air calibration correction values of the second air calibration vector for each energy bin of the detector, and a second air calibration correction value of the first air calibration vector for the energy bin normalized by a sum of the air calibration correction values of the first air calibration vector for each energy bin of the detector (Zhan, [0056] the system generates a forward calibration model (figure (1) of Zhan, shown below), [0057]-[0058] where the model shows that the total air calibration/air flux data is denoted by N0 , this is multiplied by the summed change in the values of the calibration data at each bin (Sb ) (Normalization by the sum of values), the integral is then taken of this function, which is functionally equivalent to a ratio of the first value over the second values normalized by the total flux when the integral is evaluated, this is done for each bin as shown in equation (1), this generates a normalized calibration bin response function Swb (E ));
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(Zhan, [0056]-[0058])
and divide the corrected projection data for the energy bin by the sum of the air calibration correction values of the first air calibration vector for each energy bin of a relevant detector (Zhan, [0058] the system determines a calibration function referred to as the bin weighted response function (Swb )(Air calibration correction values) where each value of Sb is a normalized air calibration value for each bin, [0079] and [0080] Swb is determined using equation (7), which takes the estimated calibration values and divides each bin by this value, this is done for each pixel in the slab, shown below is the bin projection data (Nb ) which is divided by the summed corrected air calibration data (Swb )),
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(Zhan, equation 7, where N is the projection data for each bin and Swb (E’) is the normalized summed air calibration data)
and multiply the result by the ratio to obtain a normalized photon count at the energy bin of the detector (Zhan, [0079] and [0080] and equation 7, Swb (E ) is the ratio of the air vector values is multiplied by the other values of in equation (7) where Nb is the values of the bin data and Swb (E’) is the normalized sum of the calibration data, per [0059] this estimation is used to normalized and calibrate the photon count rates).
Regarding claim 17 the combination of Zhan and Stayman teaches; The PCCT system of claim 11, wherein the first focal spot size is an extra-large (XL) focal spot, and the second focal spot size is one of a large (L) focal spot, a small (S) focal spot, and an extra-small (XS) focal spot (Stayman, [0030] the system may use two focal spots, where one or both focal spots may be large or small, alternatively, one spot may be large and one may be small, where in [0039] Stayman notes that spot sizes range from .4mm to 1 mm, applicant notes in [0065] the focal spots have four sizes, XS, S, L and XL, where per [0066] of the applicant’s specification the focal spot size ranges from .3 mm to 2 mm), the actual spot size corresponding to each of the XS, S, L and XL spots are not explicitly disclosed, therefore the examiner is interpreting any focal spot size within the range given as being acceptable, and further the examiner will consider having two focal spots, where one is disclosed as being larger than the other as being analogous to a first spot of size XL and a second spot of one of the following sizes; XS, S, or L).
The combination of Zhan and Stayman would have been obvious to one of ordinary skill in the art prior to the effective filing date of the presently claimed invention. The motivation for the combination lies in that Stayman’s teaching of using two different focal spot sizes allows for finer resolution in the resulting captured images (Stayman [0008]-[0010]).
4. Claim(s) 9-10 and 18-20 are rejected under 35 U.S.C. 103 as being unpatentable over Zhan (US 20220296202 A1) in view of Stayman (WO 2024072979 A1, Published 04/04/2024) and in further view of Frerking (WO 2022096401 A1).
Regarding claim 9 the combination of Zhan and Stayman fail to teach; The method of claim 6, wherein:
in a first condition where the first focal spot is an XL focal spot, a first MD calibration vector associated with the XL focal spot is applied to the projection data;
and in a second condition where the first focal spot is an L focal spot, a second MD calibration vector associated with the L focal spot is not applied,
and the first MD calibration vector associated with the XL focal spot is applied to the projection data.
However, in the same field of endeavor of photon counting CT calibration, Frerking teaches;
The method of claim 6, wherein:
in a first condition where the first focal spot is an XL focal spot, a first MD calibration vector associated with the XL focal spot is applied to the projection data (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first MD Calibration vector to one set of projection data), where according to page 10, lines 29-35, the filtered data is used perform Material Decomposition (MD Calibration vector), this filtering is only done for the first set of data generated for a first focal spot, and is therefore analogous to applying a MD calibration vector for a condition where the first focal spot is a set size);
and in a second condition where the first focal spot is an L focal spot, a second MD calibration vector associated with the L focal spot is not applied (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first MD Calibration vector to one set of projection data), where according to page 10, lines 29-35, the filtered data is used perform Material Decomposition (MD Calibration vector), this filtering is only done for the first set of data generated for a first focal spot, and is therefore analogous to applying a MD calibration vector for a condition where the first focal spot is a set size, this application of the filter is not done for the second focal spot, given that there are two spots of two different sizes, the system will always apply a filter to one, and not apply a filter to the second, where the spots differ in sizes, therefore this is analogous to the claimed limitation),
and the first MD calibration vector associated with the XL focal spot is applied to the projection data (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first MD Calibration vector to one set of projection data), where according to page 10, lines 29-35, the filtered data is used perform Material Decomposition (MD Calibration vector), this filtering is only done for the first set of data generated for a first focal spot, and is therefore analogous to applying a MD calibration vector for a condition where the first focal spot is a set size).
The combination of Zhan, Stayman and Frerking would have been obvious to one of ordinary skill in the art prior to the filing date of the presently claimed invention. The motivation for the combination lies in that the conditional filtering and material decomposition of Frerking based on focal spots would improve the resolution and help mitigate image artifacts (Frerking, Background of invention section)
Regarding claim 10 the combination of Zhan, Stayman and Frerking teaches; The method of claim 6, wherein:
in a first condition where the first focal spot is an S focal spot, a third MD calibration vector associated with the S focal spot is applied to the projection data (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first MD Calibration vector to one set of projection data), where according to page 10, lines 29-35, the filtered data is used perform Material Decomposition (MD Calibration vector), this filtering is only done for the first set of data generated for a first focal spot, and is therefore analogous to applying a MD calibration vector for a condition where the first focal spot is a set size);
and in a second condition where the first focal spot is an XS focal spot, a fourth MD calibration vector associated with the XS focal spot is not applied (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first MD Calibration vector to one set of projection data), where according to page 10, lines 29-35, the filtered data is used perform Material Decomposition (MD Calibration vector), this filtering is only done for the first set of data generated for a first focal spot, and is therefore analogous to applying a MD calibration vector for a condition where the first focal spot is a set size, this application of the filter is not done for the second focal spot, given that there are two spots of two different sizes, the system will always apply a filter to one, and not apply a filter to the second, where the spots differ in sizes, therefore this is analogous to the claimed limitation),
and the third MD calibration vector associated with the S focal spot is applied to the projection data(Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first MD Calibration vector to one set of projection data), where according to page 10, lines 29-35, the filtered data is used perform Material Decomposition (MD Calibration vector), this filtering is only done for the first set of data generated for a first focal spot, and is therefore analogous to applying a MD calibration vector for a condition where the first focal spot is a set size).
The combination of Zhan, Stayman and Frerking would have been obvious to one of ordinary skill in the art prior to the filing date of the presently claimed invention. The motivation for the combination lies in that the conditional filtering and material decomposition of Frerking based on focal spots would improve the resolution and help mitigate image artifacts (Frerking, Background of invention section)
Regarding claim 18 the combination of Zhan, Stayman and Frerking teaches; The PCCT system of claim 11, wherein further instructions are stored in the non-transitory memory that when executed, cause the processor to: during a calibration stage of the PCCT system (Zhan, [0151] the system contains a memory and a processing device which are connected to the DAS discloses in [0150]):
generate and store in the non-transitory memory a set of pile-up calibration vectors, a set of tube current calibration vectors, a set of air calibration vectors, and a set of MD calibration vectors for a focal spot of a first size (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts, [0009] a tube angle is computed to be used in calibration/correction, which is being interpreted as being analogous to a tube current calibration correction value, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0005] material decomposition is performed on projection data generated from the CT scan to calibrate the CT scanner [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, where as per the calibration calculations described in [0070]-[0080] of Zhan, the system uses matrices of vectors to store the data);
and generate and store in the non-transitory memory a set of air calibration vectors and a set of tube current calibration vectors for focal spots of a different size than the first size (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first Calibration vector to one set of projection data), where according to page 10, lines 29-35, this application of the filter is not done for the second focal spot, given that there are two spots of two different sizes, the system will always apply a filter to one, and not apply a filter to the second, where the spots differ in sizes, therefore this is analogous to the claimed limitation),
and not generate a set of MD calibration vectors for the focal spots of the different size (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first Calibration vector to one set of projection data), where according to page 10, lines 29-35, this application of the filter is not done for the second focal spot, given that there are two spots of two different sizes, the system will always apply a filter to one, and not apply a filter to the second, where the spots differ in sizes, therefore this is analogous to the claimed limitation).
The combination of Zhan, Stayman and Frerking would have been obvious to one of ordinary skill in the art prior to the filing date of the presently claimed invention. The motivation for the combination lies in that the conditional filtering and material decomposition of Frerking based on focal spots would improve the resolution and help mitigate image artifacts (Frerking, Background of invention section)
Regarding claim 19 the combination of Zhan, Stayman and Frerking teaches; The PCCT system of claim 18, wherein further instructions are stored in the non-transitory memory that when executed, cause the processor to (Zhan, [0151] the system contains a memory and a processing device which are connected to the DAS discloses in [0150]):
during the calibration stage: generate and store in the non-transitory memory a set of pile-up calibration vectors, a set of tube current calibration vectors, a set of air calibration vectors, and a set of MD calibration vectors for a first focal spot of the first size and a second focal spot of a second size (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts, [0009] a tube angle is computed to be used in calibration/correction, which is being interpreted as being analogous to a tube current calibration correction value, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0005] material decomposition is performed on projection data generated from the CT scan to calibrate the CT scanner [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, where as per the calibration calculations described in [0070]-[0080] of Zhan, the system uses matrices of vectors to store the data);
and generate and store in the non-transitory memory a set of air calibration vectors and a set of tube current calibration vectors for focal spots of a different size than both of the first size and the second size (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first Calibration vector to one set of projection data), where according to page 10, lines 29-35, this application of the filter is not done for the second focal spot, given that there are two spots of two different sizes, the system will always apply a filter to one, and not apply a filter to the second, where the spots differ in sizes, therefore this is analogous to the claimed limitation),
and not generate a set of MD calibration vectors for focal spots of a different size than both of the first size and the second size (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first Calibration vector to one set of projection data), where according to page 10, lines 29-35, this application of the filter is not done for the second focal spot, given that there are two spots of two different sizes, the system will always apply a filter to one, and not apply a filter to the second, where the spots differ in sizes, therefore this is analogous to the claimed limitation).
The combination of Zhan, Stayman and Frerking would have been obvious to one of ordinary skill in the art prior to the filing date of the presently claimed invention. The motivation for the combination lies in that the conditional filtering and material decomposition of Frerking based on focal spots would improve the resolution and help mitigate image artifacts (Frerking, Background of invention section)
Regarding claim 20 the combination of Zhan, Stayman and Frerking teaches; A method for calibrating a photon counting computed tomography (PCCT) system, the method comprising:
during a calibration stage of the PCCT system: setting a focal spot size scanning parameter of the PCCT system to a first size (Zhan, [0111] the system has a first focal spot which is incident on a slab, where the first focal spot would inherently have a first focal size);
generating a set of pile-up calibration vectors, a set of tube current calibration vectors, a set of air calibration vectors, and a set of MD calibration vectors (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts, [0009] a tube angle is computed to be used in calibration/correction, which is being interpreted as being analogous to a tube current calibration correction value, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0005] material decomposition is performed on projection data generated from the CT scan to calibrate the CT scanner [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, where as per the calibration calculations described in [0070]-[0080] of Zhan, the system uses matrices of vectors to store the data);
storing the set of pile-up calibration vectors, the set of air calibration vectors, the set of tube current calibration vectors, and the set of MD calibration vectors in a memory of the PCCT system (Zhan, [0063] the system estimates a pile-up correction value, which is denoted but Pb , where [0067] the pileup calibration value is function of energy, and the bin counts, [0009] a tube angle is computed to be used in calibration/correction, which is being interpreted as being analogous to a tube current calibration correction value, [0015] as part of the scan calibration data generated, air calibration data is generated based on an air scan parameters, [0058] calibration data generated from the air scan is used to generate normalized spectrum data, [0005] material decomposition is performed on projection data generated from the CT scan to calibrate the CT scanner [0015] the system generates material decomposition data based on the scanning parameters of the calibration slab, where as per the calibration calculations described in [0070]-[0080] of Zhan, the system uses matrices of vectors to store the data);
setting the focal spot size scanning parameter of the PCCT system to a one or more different sizes, and for each size of the one or more different sizes (Stayman, [0008] the system used multiple focal spots, where the spots are a first and a second spot of different sizes, such as one smaller than the other):
generating and storing in the memory a set of air calibration vectors and a set of tube current calibration vectors, and not generating a set of MD calibration vectors (Frerking, Page 1, Background of Invention, lines 6- 30, the system captures two CT images using two different focal spots of differing sizes, page 2, lines 15-26, taking the first image data (which is generated according to a first focal spot size) and applying a filter (applying a first Calibration vector to one set of projection data), where according to page 10, lines 29-35, this application of the filter is not done for the second focal spot, given that there are two spots of two different sizes, the system will always apply a filter to one, and not apply a filter to the second, where the spots differ in sizes, therefore this is analogous to the claimed limitation).
The combination of Zhan, Stayman and Frerking would have been obvious to one of ordinary skill in the art prior to the filing date of the presently claimed invention. Zhan teaches a method of photon counting CT calibration and image reconstruction based on generated calibration data, however it does not teach focal spots having different sizes. The motivation to combine the method of Stayman with the method of Zhan lies in that the ability to reconstruct images within multiple focal spots of multiple sizes allows for reconstruction of higher resolution images (Stayman, [0027]). Further, Frerking teaches a method of calibration and image reconstruction using CTs captured with multiple focal spots, and conditional calibration methods based on focal spot size. The motivation for the addition of this feature of Frerking to the combination of Zhan and Stayman lies in that the conditional filtering and material decomposition of Frerking based on focal spots would improve the resolution and help mitigate image artifacts (Frerking, Background of invention section).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Besson, US 20040264628 A1, teaches a method of multi-spectral CT imaging, where projection data, and calibration data is generated taking focal spot size into account. Relevant figures are figures 2-9 showing the calibration and projection data processing methods.
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/J.M.E./Examiner, Art Unit 2666
/EMILY C TERRELL/Supervisory Patent Examiner, Art Unit 2666
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