Prosecution Insights
Last updated: April 19, 2026
Application No. 17/204,657

USE OF MAGNETIC ELEMENTS TO SHAPE AND DEFOCUS CHARGED PARTICLE BEAMS

Non-Final OA §103
Filed
Mar 17, 2021
Examiner
OSENBAUGH-STEWART, ELIZA W
Art Unit
2881
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Varian Medical Systems, Inc.
OA Round
3 (Non-Final)
73%
Grant Probability
Favorable
3-4
OA Rounds
2y 6m
To Grant
90%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
485 granted / 662 resolved
+5.3% vs TC avg
Strong +16% interview lift
Without
With
+16.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
63 currently pending
Career history
725
Total Applications
across all art units

Statute-Specific Performance

§101
2.5%
-37.5% vs TC avg
§103
45.1%
+5.1% vs TC avg
§102
21.8%
-18.2% vs TC avg
§112
24.9%
-15.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 662 resolved cases

Office Action

§103
DETAILED ACTION This Office action is in response to the request for continued examination filed on March 2nd, 2026. Claims 1, 3-8, 10-12, 14-15, and 17-24 are pending. 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 . 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. Claim(s) 1, 4-8, 10, 12, 14-15, 17, and 19-24 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 2022/0323792 (Felici et al.). US 2013/0231516 (Loo et al.) is relied upon to show inherency of exit window. Regarding claim 1, Felici et al. discloses a radiotherapy treatment system, comprising: a source of an electron beam (“electron beam”); a linear accelerator coupled to the source, the linear accelerator configured to accelerate electrons in the electron beam (“a medical radiofrequency accelerator,”); and a beam transport subsystem coupled to the linear accelerator, the beam transport subsystem including a plurality of magnetic elements (“a set (two or three) of defocusing electromagnetic quadrupoles,”) downstream of the linear accelerator (“optical system (a quadrupole is used, for example), positioned downstream of the system.”), wherein the plurality of magnetic elements are configured to defocus the electron beam, and change a cross-sectional shape and size of the electron beam by varying field strengths of the plurality of magnetic elements before the electron beam exits the beam transport subsystem (“On the basis of the control of the values of said absorbed dose and of said energy of the charged particle beam, said magnetic field and said optical system (20) are set so as to determine the geometry of said charged particle beam.”). Felici et al. does not specifically disclose an exit window downstream of the plurality of magnetic elements. Such exit windows are an inherent feature of electron beam radiotherapy systems, as disclosed by Loo et al. (“a vacuum window is necessary to separate the vacuum of the accelerator beam line from the open air and the patient,”). Therefore, the exit window is present in Felici et al., even if not explicitly disclosed. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to place the quadrupoles between the linear accelerator and the exit window so that the electron beam is exposed to non-vacuum for the minimal distance possible. Regarding claim 4, Felici et al. discloses the system of Claim 1, wherein the plurality of magnetic elements is further configured to shape the electron beam before the electron beam exits the beam transport subsystem (“On the basis of the control of the values of said absorbed dose and of said energy of the charged particle beam, said magnetic field and said optical system (20) are set so as to determine the geometry of said charged particle beam.”). Regarding claim 5, Felici et al. discloses the system of Claim 1, wherein the plurality of magnetic elements comprise at least two quadrupole magnets (“a set (two or three) of defocusing electromagnetic quadrupoles,”). Regarding claim 6, Felici et al. discloses the system of Claim 5, wherein the at least two quadrupole magnets have tunable field strengths (“On the basis of the control of the values of said absorbed dose and of said energy of the charged particle beam, said magnetic field and said optical system (20) are set so as to determine the geometry of said charged particle beam.”). Regarding claim 7, Felici et al. discloses the claimed invention except for at least one of: solenoids; sextupole magnets; or octupole magnets. All three are well-known forms of magnetic lenses. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to substitute a sextupole or octupole magnets for the quadrupole magets since the additional poles allow for the ability to steer or correct astigmatism. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to substitute a solenoid for the quadrupole magnets since a solenoid is simpler and more compact. Regarding claim 8, Felici et al. discloses a radiotherapy treatment method, comprising: generating an electron beam (“electron beam”); accelerating electrons in the electron beam (“a medical radiofrequency accelerator,”); guiding the electron beam inside a waveguide (“accelerating guide”); defocusing the electron beam using a plurality of magnetic elements (“a set (two or three) of defocusing electromagnetic quadrupoles,”); and changing a cross-sectional shape and size of the electron beam by varying field strengths of the plurality of magnetic elements (“On the basis of the control of the values of said absorbed dose and of said energy of the charged particle beam, said magnetic field and said optical system (20) are set so as to determine the geometry of said charged particle beam.”). Felici et al. does not explicitly disclose an exit window that separates an inside of the waveguide from outside air. Such exit windows are an inherent feature of electron beam radiotherapy systems, as disclosed by Loo et al. (“a vacuum window is necessary to separate the vacuum of the accelerator beam line from the open air and the patient,”). Therefore, the exit window is present in Felici et al., even if not explicitly disclosed. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to defocus the electron beam before the beam reaches the exit window because the magnetic lens works best on an electron beam in a straight line along the axis, and exposure to air causes the electron beam to scatter in random directions. Regarding claim 10, Felici et al. discloses the method of Claim 8, further comprising shaping the electron beam using the plurality of magnetic elements (“On the basis of the control of the values of said absorbed dose and of said energy of the charged particle beam, said magnetic field and said optical system (20) are set so as to determine the geometry of said charged particle beam.”). Regarding claim 12, Felici et al. discloses the method of Claim 8, wherein the plurality of magnetic elements comprise at least two quadrupole magnets (“a set (two or three) of defocusing electromagnetic quadrupoles,”). Regarding claim 14, Felici et al. discloses the claimed invention except for at least one of: solenoids; sextupole magnets; or octupole magnets. All three are well-known forms of magnetic lenses. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to substitute a sextupole or octupole magnets for the quadrupole magets since the additional poles allow for the ability to steer or correct astigmatism. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to substitute a solenoid for the quadrupole magnets since a solenoid is simpler and more compact. Regarding claim 15, Felici et al. discloses a radiotherapy treatment method, comprising: generating an electron beam (“electron beam”); accelerating electrons in the electron beam (“a medical radiofrequency accelerator,”); guiding the electron beam inside a waveguide (“accelerating guide”); and changing a cross-sectional shape and size of the beam during treatment of a patient by varying field strengths of a plurality of magnetic elements (“On the basis of the control of the values of said absorbed dose and of said energy of the charged particle beam, said magnetic field and said optical system (20) are set so as to determine the geometry of said charged particle beam.”). Felici et al. does not explicitly disclose an exit window that separates an inside of the waveguide from outside air. Such exit windows are an inherent feature of electron beam radiotherapy systems, as disclosed by Loo et al. (“a vacuum window is necessary to separate the vacuum of the accelerator beam line from the open air and the patient,”). Therefore, the exit window is present in Felici et al., even if not explicitly disclosed. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to defocus the electron beam before the beam reaches the exit window because the magnetic lens works best on an electron beam in a straight line along the axis, and exposure to air causes the electron beam to scatter in random directions. Regarding claim 17, Felici et al. discloses the method of claim 15, further comprising defocusing the electron beam using the plurality of magnetic elements (“a set (two or three) of defocusing electromagnetic quadrupoles,”). Regarding claim 19, Felici et al. discloses the method of claim 15, wherein the plurality of magnetic elements comprise at least two quadrupole magnets (“a set (two or three) of defocusing electromagnetic quadrupoles,”). Regarding claim 20, Felici et al. discloses the claimed invention except for at least one of: solenoids; sextupole magnets; or octupole magnets. All three are well-known forms of magnetic lenses. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to substitute a sextupole or octupole magnets for the quadrupole magets since the additional poles allow for the ability to steer or correct astigmatism. It would have been obvious to a person having ordinary skill in the art at the time the application was filed to substitute a solenoid for the quadrupole magnets since a solenoid is simpler and more compact. Regarding claim 21, Felici et al. discloses the system of Claim 1, wherein the beam transport subsystem does not include a component between the plurality of magnetic elements and the exit window (“(a quadrupole is used, for example), positioned downstream of the system.”, also fig. 6 shows the magnetic optical system is the final element). Regarding claim 22, Felici et al. discloses the system of Claim 1, wherein the plurality of magnetic elements are configured to defocus the electron beam by broadening the electron beam in transverse directions relative to a longitudinal axis of the electron beam and shape the broadened electron beam before the electron beam exits the beam transport subsystem (intended use, only requires the plurality of magnetic elements to have at least 4 poles and accept varying field, also “a set (two or three) of defocusing electromagnetic quadrupoles,” see also fig. 5). Regarding claim 23, Felici et al. discloses the system of Claim 1, wherein the plurality of magnetic elements are configured to change the cross-sectional shape and size of the electron beam by broadening the electron beam in a first transverse direction relative to a longitudinal axis of the electron beam by a first amount and broadening the electron beam in a second transverse direction relative to the longitudinal axis of the electron beam by a second amount, wherein the second amount is different from the first amount (intended use, only requires the plurality of magnetic elements to have at least 4 poles and accept varying field, also “On the basis of the control of the values of said absorbed dose and of said energy of the charged particle beam, said magnetic field and said optical system (20) are set so as to determine the geometry of said charged particle beam.”). Regarding claim 24, Felici et al. discloses the system of Claim 23, wherein the plurality of magnetic elements includes at least two quadrupole magnets having tunable field strengths (also “a set (two or three) of defocusing electromagnetic quadrupoles,”), and the at least two quadrupole magnets are configured to change the cross- sectional shape and size of the electron beam by being tuned to different tuning field strengths from each other (inherent in having tuneable field strengths). Claim(s) 3, 11, and 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Felici et al. as applied to claims 1, 8, and 15 above, and further in view of US 2013/0231516 (Loo et al.). Regarding claims 3, 11, and 18, Felici et al. discloses the claimed invention except for a plurality of bending magnets, and wherein the plurality of magnetic elements are between the plurality of bending magnets and the exit window. Loo et al. disclose a radiotherapy treatment system with a beam transport system comprising a plurality of bending magnets (fig. 8, elements 14, 16, and 18). It would have been obvious to a person having ordinary skill in the art at the time the application was filed to modify the invention of Felici et al. to include the bending magnets of Loo et al. so that the beam could be steered as needed. It would be obvious to place plurality of magnetic elements between the plurality of bending magnets and the exit window so that the beam would be straight as it moves through the monitors in the guide. Response to Arguments Applicant’s arguments, see remarks, filed March 2nd, 2026, been fully 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. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ELIZA W OSENBAUGH-STEWART whose telephone number is (571)270-5782. The examiner can normally be reached 10am - 6pm Pacific Time M-F. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Robert Kim can be reached at 571-272-2293. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ELIZA W OSENBAUGH-STEWART/Primary Examiner, Art Unit 2881
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Prosecution Timeline

Mar 17, 2021
Application Filed
May 06, 2025
Non-Final Rejection — §103
Aug 05, 2025
Response Filed
Sep 30, 2025
Final Rejection — §103
Dec 23, 2025
Response after Non-Final Action
Mar 02, 2026
Request for Continued Examination
Mar 11, 2026
Response after Non-Final Action
Mar 23, 2026
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
73%
Grant Probability
90%
With Interview (+16.4%)
2y 6m
Median Time to Grant
High
PTA Risk
Based on 662 resolved cases by this examiner. Grant probability derived from career allow rate.

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