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 .
Response to Arguments
Applicant's arguments filed with the latest amendment have been fully considered. The prior anticipation rejection over Cho alone is withdrawn. The present action relies on the combined teachings of the references.
Applicant’s arguments with respect to the independent claims have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
For claim 1, Cho supplies the intrinsic-background coincidence timing framework, and Rothfuss supplies the baseline/test timing drift comparison.
For claim 11, Cho supplies intrinsic-background crystal-map generation, and Wang supplies the flood-map/LUT bright-spot-cluster to crystal-label relationship. For claim 16, Cho supplies the coincidence-mode filtered background energy spectra, and Cooke supplies the peak/corrected-peak energy calibration teaching.
Applicant's argument that Cho alone does not expressly teach the newly amended independent-claim features is not persuasive against the present rejections because the present rejections are not based on Cho alone. The obviousness inquiry asks what the combined teachings would have suggested to a person of ordinary skill in the art, not whether each feature is expressly disclosed in the primary reference alone.
Claim Rejections - 35 USC § 103
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.
Claims 1-4, and 6-10 are rejected under 35 U.S.C. §103 as being unpatentable over Cho et al. (US Pub. 2016/0299240 A1) in view of Rothfuss et al. (US Pub. 2015/0301201 A1).
With regard to claim 1,Cho teaches obtaining a first background event of a crystal of a detector of an imaging device and obtaining a second background event of the crystal, each background event being related to an inherent radiating particle of the crystal, because Cho teaches Lu-176 intrinsic background radiation in LSO scintillator crystals and acquisition of self-activity/background events from detector units, Cho [0031]-[0034], [0038], (Figure 2).
Cho further teaches determining at least one background coincidence event based on background events, because Cho teaches that coincidence mode collects an event when triggers from two adjacent detector units fall into a short time window, and teaches identifying coincidence events using energy information and time marks from detector units, Cho [0038]-[0041], [0056], (Figures 4 & 5).
Cho further teaches determining timing drift or timing correction information from background coincidence events, because Cho teaches time-mark difference histograms, deriving time-walk correction tables, correcting measured time differences for time-of-flight based on the distance between scintillator crystals, deriving average time differences between scintillator crystals, and building time alignment tables, Cho [0064]-[0075], [0078]-[0081], (Figures 5, 11 & 12).
Cho, however, does not expressly teach (1) "the second background event is obtained after completing correcting an energy state of the imaging device" and (2) "the first background event is obtained before completing correcting the energy state of the imaging device," in the before/after comparison order now recited in claim 1.
Rothfuss teaches deficiencies (1) and (2) by teaching a PET scanner setup/calibration process in which baseline data are acquired using intrinsic background radiation after a setup procedure, later test data are acquired using intrinsic background radiation, and calibration status is checked by comparing the later test data with the stored baseline data, Rothfuss [0027]-[0031].
Rothfuss further teaches that Lu-176 intrinsic background beta/gamma events may be used as start/stop events, that an expected TOF is calculated from known detector geometry, that a measured TOF is determined from event detection times, and that a time difference between expected TOF and measured TOF is computed to determine time alignment or misalignment, Rothfuss [0024]-[0025], [0033]-[0034], (Figures 7 & 10).
In view of the utility of baseline/test intrinsic-background comparison for automatically detecting calibration drift, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Cho to obtain a first intrinsic-background event before completion of an energy-state correction and a second intrinsic-background event after completion of the energy-state correction, such as taught by Rothfuss, thereby predictably allowing Cho's intrinsic-background coincidence timing data to indicate TOF drift before and after energy-state correction.
With regard to claim 2, Cho teaches obtaining the first background event based on a preset energy window because Cho teaches applying an energy window for each detector unit and using energy and timing to identify coincident background events, Cho [0042], [0056], [0059]. The inherited deficiency identified with respect to claim 1 remains addressed by Rothfuss as discussed above.
With regard to claim 3, Cho teaches correcting the energy state of the imaging device based on the first background event because Cho teaches energy scaling, non-linearity correction, comparing self-activity gamma peak locations to initial setup/stored peak locations, and adjusting detector operating parameters to correct drift, Cho [0062]-[0067], [0082]-[0088], (Figure 13). The inherited deficiency identified with respect to claim 1 remains addressed by Rothfuss as discussed above.
With regard to claim 4, Cho teaches obtaining a third background event that includes a background single event or a background coincidence event because Cho teaches singles mode, coincidence mode, and repeated acquisition of intrinsic self-activity event data from Lu-176 background radiation, Cho [0038], [0040]-[0042], [0053]-[0056].
With regard to claim 6, Cho teaches the additional limitation of at least two energy peak values associated with a nuclide decay because Cho teaches Lu-176 202 keV and 307 keV peaks and measured energy values obtained from Gaussian peak fitting, Cho [0034], [0066]-[0067], (Figures 2 & 8). Cooke further teaches using 202 keV and 307 keV Lu-176 characteristic peaks for gain and energy calibration, Cooke [0034]-[0038], (Figures 2-7).
With regard to claims 7-10, Cho teaches the additional timing limitations because Cho teaches time-mark difference histograms, measured time differences, time-walk correction, TOF correction based on crystal distance, individual timing offsets, and scanner time alignment, Cho [0041], [0064]-[0075], [0078]-[0081], (Figures 5, 11 & 12). Rothfuss further teaches expected TOF, measured TOF, computing a time difference, and determining time misalignment from intrinsic-background Lu-176 events, Rothfuss [0024]-[0025], [0033]-[0034], (Figures 7 & 10).
Claim 5 is rejected under 35 U.S.C. §103 as being unpatentable over Cho in view of Rothfuss and Cooke et al. (US Pub. 2008/0251709 A1).
With regard to claim 5, Cho teaches generating an energy spectrogram based on energy information of a background event, determining at least one peak position in the energy spectrogram, and correcting an energy state based on peak information because Cho teaches energy spectra from self-activity/background events, 202 keV and 307 keV gamma peaks, Gaussian fitting of peak values, energy scaling, non-linearity correction, and drift correction, Cho [0040]-[0041], [0062]-[0067], [0082]-[0088], (Figures 4, 5, 8 & 13).
Cho, however, does not expressly teach "wherein the corrected peak position is determined based on the peak position of the energy spectrogram obtained from a radiation source."
Rothfuss teaches the radiation-source setup context by teaching gain balancing based on detected radiation from a radioactive calibration source placed in the PET scanner field of view, determining a 511 keV photopeak during source-based full setup, and then acquiring baseline intrinsic-background data including crystal energy spectrum/photopeak data, Rothfuss [0027]-[0029].
Cooke teaches peak/channel alignment by teaching conventional radioactive-source calibration in which a radioactive calibration source produces radiation of characteristic energy and gain is determined so that output from the characteristic-energy radiation is placed into the corresponding output energy channel, Cooke [0003]. Cooke further teaches using Lu-176 202 keV and 307 keV peaks, singles and coincidence spectra, gain LUTs, amplitude correction LUTs, and aligning detected peaks with ideal/preselected characteristic peaks or channels, Cooke [0034]-[0038], (Figures 2-7).
In view of the utility of source-derived peak positions for providing a known calibration reference in PET detector energy calibration, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Cho to determine the corrected peak position based on a peak position of an energy spectrogram obtained from a radiation source, such as taught by Rothfuss and Cooke, thereby predictably providing a reference peak position for comparing and correcting intrinsic-background energy peak drift.
Claims 16, 17, 19, and 39 are rejected under 35 U.S.C. §103 as being unpatentable over Cho in view of Cooke.
With regard to claim 16, Cho teaches obtaining a background event of a crystal of a detector of an imaging device, the background event being related to an inherent radiating particle of the crystal, because Cho teaches Lu-176 intrinsic background radiation in LSO scintillator crystals and acquiring self-activity/background events from detector units, Cho [0031]-[0034], [0038], (Figure 2).
Cho teaches generating an energy spectrogram based on energy information of the background event and determining at least one peak position in the energy spectrogram because Cho teaches energy spectra of acquired self-activity data, including singles-mode and coincidence-mode energy spectra having 202 keV and 307 keV gamma peaks, Cho [0040]-[0041], [0059], (Figures 4, 5 & 8).
Cho teaches obtaining the background event in a coincident event mode based on at least one of a preset time window or preset energy window, filtering particle energy information based on arrival time, and generating the energy spectrogram based on the filtered particle energy information because Cho teaches collecting coincidence-mode events when two adjacent detector-unit triggers fall into a short time window and using energy windows and time marks to identify coincident events, Cho [0038]-[0042], [0056], (Figures 4 & 5).
Cho further teaches determining measured energy values from Gaussian fits on the 202 keV and 307 keV peaks of the coincidence event energy spectrum and using those values for energy scaling and non-linearity correction, Cho [0066]-[0067], (Figure 8).
Cho, however, does not expressly teach determining the energy correction state based on a corrected peak position in the form now recited in claim 16.
Cooke teaches determining an energy correction state based on peak and corrected/reference peak positions by teaching a self-calibration processor that uses Lu-176 characteristic radiation, including 202 keV and 307 keV peaks, peak detectors, gain adjustment, gain LUTs, amplitude correction LUTs, and aligning detected peaks with ideal or preselected characteristic peaks/channels, Cooke [0034]-[0038], (Figures 2-7).
In view of the utility of aligning intrinsic Lu-176 peak positions to known ideal or preselected characteristic peak/channel positions for PET detector energy calibration, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Cho to determine the energy correction state based on the peak position and a corrected peak position, such as taught by Cooke, thereby predictably improving energy calibration and detector stability.
With regard to claim 17, Cho teaches generating an energy spectrogram in single-event/singles mode because Cho teaches energy spectra of all decay events acquired in singles mode, Cho [0038], [0040], (Figure 4). Cooke further teaches a Lu-176 singles energy spectrum and characteristic peak calibration using Lu-176 background radiation, Cooke [0031], [0034]-[0035], (Figures 2, 5 & 6).
With regard to claim 19, Cho teaches comparing gamma peak locations to initial setup or previously stored peak locations and correcting drift, Cho [0082]-[0088], (Figure 13). Cooke teaches comparing detected characteristic peaks with ideal/preselected characteristic peaks or corresponding channels and adjusting gain or scaling accordingly, Cooke [0035]-[0038]. The claimed ratio of peak position to corrected peak position is an obvious numerical comparison of the measured peak and the reference/corrected peak used to determine whether the energy correction state is abnormal.
With regard to claim 39, Cho teaches energy spectra in which PET-relevant full-energy qualification is used, including 511 keV energy qualification in timing-performance measurement, Cho [0048], [0059]. Cooke teaches peak-based calibration using detected characteristic peaks and ideal/preselected characteristic peak/channel alignment, Cooke [0034]-[0038].
Claims 20 and 40 are rejected under 35 U.S.C. §103 as being unpatentable over Cho in view of Cooke, as applied to claim 16 above, and further in view of Rothfuss.
With regard to claim 20, For the limitations inherited from claim 16, refer to the rejection of claim 16 above. Cho and Cooke, however, do not expressly teach the corrected peak position corresponding to a peak position of at least one photon of 511 keV in the energy spectrum with the same source/full-setup clarity recited by claim 20.
Rothfuss teaches determining 511 keV photopeak information during PET scanner full setup using a radioactive calibration source placed in the field of view, Rothfuss [0027]-[0029].
In view of the utility of 511 keV photopeak information for PET scanner energy calibration, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to further modify the Cho-Cooke energy calibration process to use a corrected peak position corresponding to a 511 keV photon peak, such as taught by Rothfuss, thereby predictably providing a PET-standard energy reference for calibration.
With regard to claim 40, For the limitations inherited from claim 16, refer to the rejection of claim 16 above. Cho teaches time-mark difference histograms of two detector units and a short coincidence time window for background coincidence events, Cho [0041], [0056], (Figure 5). Cho and Cooke, however, do not expressly teach "the range of the time window is determined based on a time resolution" where "the time resolution refers to a half height and full width of a time difference distribution corresponding to two detectors in a background coincidence event."
Rothfuss teaches computing time differences between expected TOF and measured TOF for intrinsic-background Lu-176 events and generating a histogram of the plurality of time differences to evaluate time alignment or time misalignment, Rothfuss [0033]-[0034], (Figure 10).
In view of the utility of timing-resolution-based coincidence windows for selecting true background coincidence events and rejecting mis-timed events, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to further modify Cho to determine the time-window range based on the width of a time-difference distribution, such as the time-difference histogram taught by Rothfuss, thereby predictably setting the coincidence window according to measured detector timing resolution.
Claims 11-13 and 15 are rejected under 35 U.S.C. §103 as being unpatentable over Cho in view of Wang et al. (US Pub. 2015/0331119 A1).
With regard to claim 11, Cho teaches obtaining a background event of a crystal of a detector, the background event being related to an inherent radiating particle of the crystal, because Cho teaches Lu-176 intrinsic background radiation in LSO scintillator crystals and acquisition of self-activity event data, Cho [0031]-[0034], [0038], (Figure 2).
Cho teaches determining position information and crystal maps from background event data because Cho teaches that the identity of which crystal is impacted may be ascertained using a crystal map, and teaches assigning events within detector units to individual scintillator crystals by generating histogram event locations and deriving crystal region maps, Cho [0030], [0055], [0068], (Figures 7 & 9).
Cho, however, does not expressly teach (1) "wherein each bright spot cluster in the single-event image is a group of pixels in the single-event image," (2) "the each bright spot cluster represents a mapping position of one of crystals in the detector, and has a corresponding crystal position label," and (3) "obtaining, based on the single-event image, a first corresponding relationship between the each bright spot cluster in the single-event image and the corresponding crystal position label."
Wang teaches deficiencies (1)-(3) by teaching PET crystal decoding using a lookup table generated from a flood map, where the flood map is a density plot of Anger arithmetic positions for many scintillation events, each peak or high-density region corresponds to a different scintillator element, and the lookup table is generated by defining boundaries between flood-map peaks and assigning areas to respective scintillator elements, Wang [0011]-[0013], [0031]-[0033], (Figures 2A-2C).
In view of the utility of flood-map lookup-table crystal decoding for reducing incorrect scintillator assignment and improving spatial, energy, and timing resolution, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Cho to correct the crystal-position look-up table based on the relationship between event-image clusters and corresponding crystal position labels, such as taught by Wang, thereby predictably improving Cho's crystal map based event assignment.
With regard to claim 12, Cho teaches determining an energy window and obtaining the background event based on the energy window because Cho teaches energy-window qualification and identifying coincidence events using energy windows and timing, Cho [0042], [0056], [0059]. The inherited deficiencies identified with respect to claim 11 remain addressed by Wang as discussed above.
With regard to claim 13, Cho teaches determining a single-characteristic-energy-peak event based on a background event because Cho teaches Lu-176 decay in LSO and characteristic decay energies used for self-setup and self-calibration, including the Lu-176 decay diagram showing the 597 keV level and associated beta/gamma decay scheme, Cho [0034], (Figure 2). The inherited deficiencies identified with respect to claim 11 remain addressed by Wang as discussed above.
With regard to claim 15, Cho teaches using background event information to generate crystal maps and perform detector correction/stabilization, Cho [0055], [0068], [0082]-[0088], (Figures 9 & 13). Wang teaches that incorrect crystal decoding and flood-map peak ambiguity cause scintillation events to be assigned to incorrect scintillator elements, thereby degrading spatial, energy, and timing resolution, Wang [0012]-[0013], [0033]-[0034]. Thus, Wang teaches determining whether a deviation related to the crystal-position lookup table has occurred based on the background-event image/cluster relationship.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Djura Malevic whose telephone number is (571) 272-5975. The examiner can normally be reached M-F (9-5).
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/DJURA MALEVIC/Examiner, Art Unit 2884
/UZMA ALAM/Supervisory Patent Examiner, Art Unit 2884
