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 .
Detailed Action
Overview
This is a first action on the merits (FAOM) to this instant application in which claims 1-16 are pending. Claims 1, 13 and 16 are independent and claims 2-12, 14-15 are dependent.
Independent claim 1 is directed to an MRI apparatus. If there is a new invention, Examiner believes, it resides in the functional limitations of the control circuitry that can be found in lines 9-19 of the instant claim 1. Examiner’s search is concentrated in this particular area of MRI art. A reference found as a result of Examiner’s search and credited to Liu et al. (US-2021/0025953-A1) appears to meet features of instant independent claim 1, see below rejection under 35 USC §102.
Rejection under 35 USC §102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. §102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-12 and 16 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Liu (US-2021/0025953-A1).
Claim No
Claim feature
Prior art
Liu (US-2021/0025953-A1)
1
An MRI apparatus comprising:
Liu discloses an MRI apparatus (1000) as claimed, see Fig. 10.
an RF coil configured to transmit an RF signal to an object;
an RF coil (1020) configured to transmit an RF signal to an object (1016);
an RF amplifier configured to output the RF signal to a load including at least the RF coil and the object, wherein the RF amplifier comprises:
an RF amplification circuit configured to amplify an inputted RF signal; and
an RF amplifier (130) configured to output the RF signal to a load including at least the RF coil (1020) and the object (1016), wherein the RF amplifier (130) comprises:
an RF amplification circuit1 configured to amplify an inputted RF signal; and
control circuitry configured to acquire load impedance information of the load in a first scan,
determine compensation data for compensating nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal based on the load impedance information, and compensate for the RF signal to be outputted from the RF amplification circuit in a second scan for each amplitude of the inputted RF signal by using the compensation data.
control circuitry (1070) configured to acquire load impedance information2 (“load characteristic of the RF coil”) of the load in a first scan,
determine compensation data for compensating nonlinearity3 of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal based on the load impedance information, and compensate for the RF signal to be outputted from the RF amplification circuit in a second scan for each amplitude of the inputted RF signal by using the compensation data.
2
The MRI apparatus according to claim 1, wherein: the RF amplifier further includes a memory that stores a plurality of nonlinearity compensation tables corresponding to a plurality of load impedances; and the control circuitry is configured to select a nonlinearity compensation table for compensating an amplitude and a phase of the inputted RF signal for each amplitude from the plurality of nonlinearity compensation tables based on the load impedance information, and determine a selected nonlinearity compensation table as the compensation data.
Claim 2 is met by Liu as it discloses a memory4 that holds linearity compensation table (table -1), see para [0019] and also see in other places in Liu.
Liu further discloses compensation values compensating an amplitude (gain) and phase5, see para [0050].
3
The MRI apparatus according to claim 1, wherein the load impedance information includes at least one of:
(a) a complex load impedance;
(b) a complex load admittance;
(c) a voltage standing wave ratio (VSWR) and a phase angle between a traveling wave and a reflected wave;
(d) a complex reflection coefficient; and
(e) S11 parameter.
Liu meets claim 3 as the coil load impedance is understood to be a complex load impedance, as the coil being a reactive element.
Liu also discusses a VSWR, see para [0066]6.
4
The MRI apparatus according to claim 2, wherein the plurality of nonlinearity compensation tables include: a reference nonlinearity compensation table corresponding to a predetermined reference load impedance; and at least one variation nonlinearity compensation table corresponding to a varying load impedance that is different from the reference load impedance.
Liu meets claim 4 as it discloses a reference load impedance and compensation therefor, see para [0066] when it discusses an ideal load impedance of 50 Ohm.
Liu meets rest of the claim feature as it discusses non-ideal load impedance, i.e., load impedance other than 50 Ohm.
5
The MRI apparatus according to claim 2, wherein the plurality of nonlinearity compensation tables include: a reference nonlinearity compensation table corresponding to a predetermined reference load impedance; and at least one difference compensation table corresponding to a difference load impedance that is difference between the reference load impedance and a varying load impedance different from the reference load impedance.
Liu meets claim 5 as it discloses a predetermined reference load impedance and compensation therefor, see para [0066] when it discusses an ideal load impedance of 50 Ohm.
Liu meets rest of the claim feature including a difference compensation table as it discusses compensation table for non-ideal load impedance, i.e., load impedance other than 50 Ohm.
6
The MRI apparatus according to claim 5, wherein the difference compensation table is used in another RF amplifier having a same configuration as the RF amplifier.
Claim 6 is within the scope of Liu as one of ordinary skill may use same compensation table for another amplifier that is identical to one at hand.
7
The MRI apparatus according to claim 4, wherein the reference load impedance is 50 Ω.
Liu meets claim 7, see para [0066].
8
The MRI apparatus according to claim 5, wherein the reference load impedance is 50 Ω.
Liu meets claim 8, see para [0066].
9
The MRI apparatus according to claim 1, wherein: the RF amplifier further includes a memory that stores an arithmetic expression for calculating at least one nonlinearity compensation value that compensates for a plurality of nonlinearities corresponding to a plurality of load impedances; and the control circuitry is configured to calculate the at least one nonlinearity compensation value for compensating the amplitude and the phase of the inputted RF signal for each amplitude by using the arithmetic expression based on the load impedance information, and determine the nonlinearity compensation value as the compensation data.
Liu meets claim 9 as it discloses a memory, see footnote 4.
The memory in Liu is understood to include arithmetic expressions as it calculates new non-linearity compensation data, for example through “interpolation”.
Liu calculates compensation data which requires arithmetic expression.
Liu generates compensation value for amplitude (gain) and phase, see various places in Liu.
10
The MRI apparatus according to claim 1, wherein the control circuitry is configured to: generate, during the first scan, a specific nonlinearity compensation table corresponding to the load impedance of the first scan; determine the specific nonlinearity compensation table as the compensation data.
Liu meets claim 10 as Liu can be understood to generate a specific compensation table, for example, by interpolation7-based calculation, see for example, para [0053] in Liu.
11
The MRI apparatus according to claim 2, wherein the plurality of nonlinearity compensation tables include more nonlinearity compensation tables near load impedances of loads assumed to be frequent in the first scan and the second scan than nonlinearity compensation tables near load impedances of loads assumed to be infrequent.
Liu meets claim 11 as it discloses plurality of tables when it generates new compensation data through interpolation using existing table.
12
The MRI apparatus according to claim 1, wherein the RF amplifier is configured to compensate for nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal by DPD (Digital Pre-Distortion) feedforward compensation.
Liu meets claim 12 as it discloses feedforward compensation when it discusses “forward feedback” numerous times in the text. See for example para [0050].
16
An RF amplifier that amplifies an inputted RF signal and outputs an amplified RF signal to a load including at least an object and an RF coil configured to transmit the amplified RF signal to the object in an MRI apparatus, the RF amplifier comprising: an RF amplification circuit configured to amplify the inputted RF signal; and control circuitry configured to acquire load impedance information of the load in a first scan, determine compensation data for compensating nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal based on the load impedance information, and compensate for the RF signal to be outputted from the RF amplification circuit in a second scan for each amplitude of the inputted RF signal by using the compensation data.
All features of claim 16 are found in claim 1, see treatment of claim 1 above for claim 16.
Allowable Subject Matter
Claims 13-15 are allowed.
The following is an examiner’s statement of reasons for allowance:
As to independent claim 13, the claim is being allowed because the prior art of the record neither discloses nor reasonably suggests an MRI apparatus comprising:
an RF coil configured to transmit an RF signal to an object; and an RF amplifier, wherein the RF amplifier comprises:
an RF amplification circuit having a power amplification element that amplifies an inputted RF signal; and
control circuitry configured to
acquire imaging conditions having been set in a scan of imaging the object, the imaging conditions including at least a pulse width, a duty cycle, and an average power value,
determine compensation data for compensating nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal depending on the imaging conditions, and compensate for the RF signal to be outputted from the RF amplification circuit in the scan for each amplitude of the inputted RF signal by using the compensation data.
Applied prior art reference Liu discloses imaging condition to include a power of the RF pulse but not pulse width and duty cycle. The claim requires all three of these parameters.
As to dependent claims 14 and 15, these claims are being allowed because each of these claims depends from allowed independent claim 13.
As to claim 3, the claim would be allowable if written in independent form because the prior art of the record neither discloses nor reasonably suggests the MRI apparatus according to claim 1, wherein the load impedance information includes at least one of: (a) a complex load impedance; (b) a complex load admittance; (c) a voltage standing wave ratio (VSWR) and a phase angle between a traveling wave and a reflected wave; (d) a complex reflection coefficient; and (e) S11 parameter.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to G.M. HYDER whose telephone number is (571)270-3896. The examiner can normally be reached on M-F 9 AM- 5 PM.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Stephanie Bloss can be reached on (571) 272-3555. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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G.M. HYDER
Primary Examiner
Art Unit 2852
/G.M. A HYDER/Primary Examiner, Art Unit 2852
1 Examiner comment: The amplifier 130 in Liu [implicitly] includes an amplification circuit, even if not shown, which is configured to amplify an input RF signal from RF generator 123.
2 Examiner comment: Liu acquires load information in a first scan, as claimed, see flow chart in Fig. 11 which discloses the claimed feature in steps 1120-1150. Then it determines a compensation data for establishing signal-linearity. The apply the compensation data for second scan, i.e., subsequent scans.
3 [0069] In one aspect, according to an embodiment of the present invention, the feedback signal-linearity compensation value-relationship may comprise a relationship between a plurality of groups of feedback signals corresponding to different load characteristics and the linearity compensation values. In other words, for example, a plurality or all items in the stored look-up tables may respectively be associated with different load characteristics (or types of objects to be scanned). That is, these lookup tables may be grouped according to corresponding load characteristics. The load may be, for example, the object to be scanned as described above. The load characteristic may be, for example, an attribute or a type of the object to be scanned, which may include the age, gender, body type, body weight, scan site and the like, which cause the object to be scanned to have different resistances. The RF output unit 120 is used to decide the load characteristics of the RF transmit coil 1020 based on the reverse feedback signal and determine a linearity compensation value for the gain and/or phase corresponding to the forward feedback signal in a group of feedback signal-linearity compensation value-relationships corresponding to the determined load characteristics and generate a linearity compensation control signal as described above based on the determined linearity compensation value.
4 [0019] Preferably, the RF transmit system further comprises a memory, for storing the predetermined feedback signal-linearity compensation value-relationship.
5 [0050] The above noted relationship between the feedback signal and (gain or phase) linearity compensation values may be represented by a lookup table which may be a one-to-one correspondence between a group of predetermined forward-feeding linearity compensation values (including gain compensation values and phase compensation values) and a group of characteristic values (such as the voltage, current, or power). In particular, it may be shown in Table 1 below, where a signal characteristic value index therein may be an orderly arranged group of index values that may sequentially point to decremental or incremental power characteristic values, such as an ideal amplitude of a power signal. The ideal amplitude may comprise an amplitude of an RF pulse that needs to be applied to an RF transmit coil determined by a scan sequence when executing a pre-scan or a formal scan by an MRI system. The lookup table values in Table 1 may be directed directly to the linearity compensation values of the gain or the phase, i.e., having a fixed linearity compensation value for each power characteristic value.
6 [0066] Further, in order to better meet the linearity requirements of MRI, the feedback signal-linearity compensation value-relationship obtained under the load of the actual object to be scanned may be used for the linearity compensation according to the RF transmit system 100 of the present invention, taking into consideration the variation of the load with respect to the entire transmit chain or even the MRI system. The curve in FIG. 6 illustrates voltage standing wave ratios (VSWR) of different human bodies, where the X-coordinate represents a working frequency and the Y-coordinate represents the VSWR. The VSWR is a ratio of the antinode voltage of the standing wave to the trough voltage amplitude and when VSWR is equal to 1, it means the resistances of the feeder line and the antenna are a complete match and at this point, the high frequency energy is completely radiated out by the antenna and there is no reflection loss of the energy. Under an ideal load of 50 Ohm that is normally used, the VSWR is equal to 1; however, under many circumstances, the human body part to be scanned can never always be a 50 Ohm load and thus the VSWR cannot be equal to 1.
7 [0053] Alternatively, in the absence of the same characteristic value, a characteristic value that is closest to such feedback signal is looked up (e.g., looking for the same or the closest power amplitude in Table 1); next, a linearity compensation value corresponding to the characteristic value that has been looked up is selected. Alternatively, the linearity compensation value corresponding to the feedback signal is calculated through interpolation calculation, based on the linearity compensation value corresponding to the characteristic value close to the feedback signal in the lookup table as shown in Table 1 above. Finally, a linearity compensation control signal is generated based on the linearity compensation value, to carry out linearity compensation with respect to the gain or phase of the output of the RF output unit 120, for example, to carry out linearity compensation with respect to the RF excitation pulses to be outputted by the RF output unit 120.