Ex Parte Panescu

Board of Patent Appeals and Interferences

Feb 13, 2009

10300706 (B.P.A.I. Feb. 13, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte DORIN PANESCU
__________

Appeal 2008-4299
Application 10/300,706
Technology Center 3700
__________

Decided:1 February 13, 2009
__________

Before DEMETRA J. MILLS, LORA M. GREEN, and
RICHARD M. LEBOVITZ, Administrative Patent Judges.

MILLS, Administrative Patent Judge.

DECISION ON APPEAL

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the decided date
shown on this page of the decision. The time period does not run from the
mail Date (paper delivery) or Notification Date (electronic delivery).

Appeal 2008-4299
Application 10/300,706

This is an appeal under 35 U.S.C. § 134. The Examiner has rejected
the claims for anticipation and obviousness. We have jurisdiction under 35
U.S.C. § 6(b).
The following claims are representative.
1. A catheter tracking system, comprising:
a catheter having a longitudinal axis;
one or more permanent magnets mounted to the catheter, a single one
of the one or more permanent magnets capable of exhibiting an
asymmetrical magnetic field about the longitudinal axis without influence
from any others of the one or more permanent magnets;
one or more magnetic sensors configured for sensing the
asymmetrical magnetic field; and
processing circuitry configured for determining the roll of the catheter
about the longitudinal axis based on the sensed asymmetrical magnetic field.
2. The system of claim 1, wherein the catheter comprises an operative
element.
8. The system of claim 1, wherein the one or more permanent magnets is
composed of plastic magnetic material.
15. The system of claim 1, wherein the single one of the one or more
permanent magnets comprises a torroidal magnet with opposite poles
aligned perpendicular to the longitudinal axis of the catheter, the torroidal
magnet having non-magnetic material between the opposite poles.
22. The system of claim 1, wherein the processing circuitry comprises a
table with magnetic field intensities as inputs and the roll of the catheter as
an output.

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Cited References

Silverstein US 5,775,322 Jul. 07, 1998
Haynor US 6,263,230 B1 Jul. 17, 2001
Hall US 6,292,678 B1 Sep. 18, 2001
Acker US 6,332, 089 B1 Dec. 18, 2001
Stumpe US 6,448,761 B1 Sep. 10, 2002
Ritter US 6,702,804 B1 Mar. 09, 2004

Grounds of Rejection
1. Claims 1, 7, 9-12, 16, 20, and 21 are rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Haynor in view of Stumpe.
2. Claims 2-6 and 17-19 are rejected under 35 U.S.C. § 103(a) as
being unpatentable over Haynor in view of Stumpe and Acker.
3. Claim 8 is rejected under 35 U.S.C. § 103(a) as being unpatentable
over Haynor in view of Stumpe and Silverstein.
4. Claim 15 is rejected under 35 U.S.C. § 103(a) as being
unpatentable over Haynor in view of Stumpe and Hall.
5. Claim 22 is rejected under 35 U.S.C. § 103(a) as being
unpatentable over Haynor in view of Stumpe and Ritter.

DISCUSSION
Background
The present invention relates to the “navigation of medical imaging
devices, and more particularly to the magnetic localization of catheters.”
(Spec. 1.)

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1. Claims 1, 7, 9-12, 16, 20 and 21 are rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Haynor in view of Stumpe.

ISSUE
The Examiner concludes that the Haynor arrangement inherently
provides an asymmetrical magnetic field about the longitudinal axis and
allows for determination of the rotational displacement, or roll, of the
catheter. In addition, all six degrees of freedom of the system may be
calculated, which gives the position in three dimensions, as well as the roll,
pitch, and yaw. (Ans. 4.)
Appellant contends that there is no explicit suggestion in Haynor or
Stumpe that the Haynor catheter can carry a single permanent magnet that
exhibits any asymmetrical magnetic field about the longitudinal axis of the
catheter. (Br. 4.)
The issue is: Does the cited prior art disclose or suggest a single
permanent magnet that exhibits an asymmetrical magnetic field about the
longitudinal axis of the catheter?

FINDINGS OF FACT
According to the Examiner:
1. Haynor discloses a system and method for determining the location and
orientation of a medical device which may be placed in the body. (Ans. 4.)
2. A medical tube is used, which includes for example catheters, guide
wires, and medical instruments, the tube has a longitudinal axis. The
medical tube has one or more permanent magnets (figure 12), which may be
aligned such that a first magnet is parallel with the longitudinal axis and a

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second magnet is perpendicular with the longitudinal axis. This arrangement
inherently provides an asymmetrical magnetic field about the longitudinal
axis and allows for determination of the rotational displacement, or roll, of
the catheter. (Ans. 4.)
3. In addition, all six degrees of freedom of the system may be calculated,
which gives the position in three dimensions, as well as the roll, pitch, and
yaw. (Ans. 4.)
4. Haynor discloses that the magnet is preferably a small cylindrical rare-
Earth magnet, such as samarium cobalt or neodymium iron boron, which
generate high field strengths per unit volume and by their inherent properties
have magnetic field intensity greater than 40 times that of Earth. (Ans. 4.)
5. In Haynor, a plurality of magnetic sensors are used to detect the location
of the magnets. (Ans. 4.)
6. Haynor fails to disclose that a single magnet is capable of exhibiting an
asymmetrical magnetic field. (Ans. 4.)
7. Stumpe discloses a rotation sensor having a permanent magnet. The
permanent magnet contains two magnetization regions that result in an
asymmetric magnetic field, as seen in figure 1. (Ans. 4.)
8. The Examiner concludes that, “It would have been obvious to one of
ordinary skill in the art at the time of the invention to have modified Haynor
et al. such that the rotation sensor comprises the sensor disclosed by Stumpe
et al. Such a modification, which involves the substitution of one known
type of rotation sensor for another, would have yielded predictable results
such as allowing for improved angle of rotation sensation of the body the
sensor is mounted on.” (Ans. 4.)
Other facts:

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9. Claim 1 uses the open ended transitional language “comprising” and does
not exclude additional elements such as the yoke of Stumpe.
10. Haynor indicates that the medical device or tube may be a catheter or
medical instrument. (Col. 4, l. 44-62.) Thus, Haynor would reasonably
appear to encompass a medical probe.
11. Haynor discloses that magnetic sensors include “Hall-effect” sensors.
(Col. 8, ll. 15.) Thus, Haynor inherently describes an asymmetric magnetic
field in its Hall effect sensors.
12. Stumpe discloses a Hall probe. (Col. 4. ll. 29-30.)

PRINCIPLES OF LAW
“[A] patent composed of several elements is not proved obvious
merely by demonstrating that each of its elements was, independently,
known in the prior art. Although common sense directs one to look with
care at a patent application that claims as innovation the combination of two
known devices according to their established functions, it can be important
to identify a reason that would have prompted a person of ordinary skill in
the relevant field to combine the elements in the way the claimed new
invention does.” KSR Int’l Co. v. Teleflex Inc., 127 S.Ct. 1727, 1731 (2007).
In determining whether a reason exists to combine prior art references a
court may “consider the inferences and creative steps a person of ordinary
skill in the art would employ.” (Id.) “The combination of familiar elements
according to known methods is likely to be obvious when it does no more
than yield predictable results.” Id. at 1739.

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ANALYSIS
The Appellant contends that the specific issue on appeal is whether
there is a suggestion in the prior art, particularly Stumpe to incorporate a
single magnet capable of exhibiting an asymmetric magnetic field within the
catheter of Haynor. (App. Br. 4.) However, the Appellant concludes there is
no suggestion in Stumpe or the cited prior art to modify the Haynor device
in this manner. (App. Br. 4.)
Appellant argues, “There is no explicit suggestion in Haynor or
Stumpe that the Haynor catheter can carry a single permanent magnet that
exhibits an asymmetrical magnetic field about the longitudinal axis of the
catheter.” (Br. 4.) Appellant further argues that “Stumpe teaches that the
rotation of a body can be measured by mounting a permanent magnet 1 on
the body and surrounding the magnet 1 with a closely spaced yoke 5, which
carries a Hall sensor 7 that senses the rotation displacement of the magnet 1
as it rotates within the yoke 5 (See Figs. 1 and 2 and corresponding text).”
(App. Br. 5.) Appellant appears to admit that the permanent magnet 1 of
Stumpe does appear to exhibit an asymmetrical magnetic field about the
body, but argues that the magnet 1/yoke 5 arrangement is intended to be
used in machinery (e.g., motors)-not catheters (See U.S. Patent Nos.
4,829,248, and 5,325,005 cited in the background of Stumpe). (App. Br. 5.)
Appellant argues that “the magnet 1/yoke 5 arrangement disclosed in
Stumpe is not suitable for catheters, since there is no place to affix the yoke
5 relative to the magnet 1.” (Br. 5.)
We are not persuaded by Appellant’s argument. Appellant has
presented no evidence to support the position that the magnet of Stumpe is
not suitable for catheters. Appellant is reminded that such arguments of

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counsel cannot take the place of evidence. In re DeBlauwe, 736 F.2d 699,
705 (Fed. Cir. 1984).
Appellant argues that the Examiner concluded that an explicit
suggestion to combine the cited references was made in Stumpe, because
Stumpe discloses a “probe” and the Haynor device is a medical probe.
Appellant disagrees. (Br. 6.) Appellant argues that “[t]he ‘probe’ that
Stumpe refers to is not a probe in the sense of an elongated probe, such as a
medical probe, but rather a probe in the sense of a device that can be
incorporated into machinery for probing or sensing rotation.” (Br. 6.)
Appellant concludes that Stumpe simply refers to a sensing device
that utilizes the Hall effect2 to determine rotation of a body-not an elongated
probe. While the yoke 5 in which the Hall probe 7 is incorporated is
elongated to the extent that it is cylindrical, the yoke 5 is not a probe, and
certainly does not suggest that the Hall probe 7 be incorporated into a
medical probe. (Br. 6.)
The Examiner responds that, in Haynor, “the medical tube has one or
more permanent magnets (figure 12), which may be aligned such that a first
magnet is parallel with the longitudinal axis and a second magnet is
perpendicular with the longitudinal axis. This arrangement inherently
provides an asymmetrical magnetic field about the longitudinal axis and

2 A phenomenon that occurs when an electric current moving through a
conductor is exposed to an external magnetic field applied at a right angle, in
which an electric potential develops in the conductor at a right angle to both
the direction of current and the magnetic field. The Hall effect is a direct
result of Lorentz forces acting on the charges in the current, and is named
after physicist Edwin Herbert Hall (1855-1938). See:
http://www.thefreedictionary.com/Hall+effect

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allows for determination of the rotational displacement, or roll, of the
catheter.” (Ans. 4.)
We agree that the Examiner has established a prima facie case of
obviousness based on the evidence herein. Haynor discloses that magnetic
sensors in its medical device with a permanent magnet may include “Hall-
effect” sensors. (FF11.) Stumpe discloses a Hall probe. (FF12.) In view of
this disclosure, we agree with the Examiner that “[i]t would have been
obvious to one of ordinary skill in the art at the time of the invention to have
modified Haynor et al. such that the rotation sensor comprises the sensor
disclosed by Stumpe et al. Such a modification, which involves the
substitution of one known type of rotation sensor which works using the
Hall effect for another, would have yielded predictable results such as
allowing for improved angle of rotation sensation of the body the sensor is
mounted on.” (Ans. 4.)
Appellant has not rebutted the Examiner’s prima facie case by
showing that the magnet arrangement in Haynor does not provide an
asymmetrical magnetic field about the longitudinal axis and allows for
determination of the rotational displacement, or roll, of the catheter. Nor has
Appellant presented evidence to support that the magnet of Stumpe is not
suitable for catheters.
The rejection of the Examiner is affirmed.

CONCLUSION OF LAW
The cited prior art discloses or suggests a single permanent magnet
that exhibits any asymmetrical magnetic field about the longitudinal axis of
the catheter. The rejection of the Examiner is affirmed.

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2. Claims 2-6 and 17-19 are rejected under 35 U.S.C. § 103(a) as
being unpatentable over Haynor in view of Stumpe and Acker. 2. Claims 2-
6 and 17-19 are rejected under 35 U.S.C. § 103(a) as being unpatentable
over Haynor in view of Stumpe and Acker. 3. Claim 8 is rejected under 35
U.S.C. § 103(a) as being unpatentable over Haynor in view of Stumpe and
Silverstein. 4. Claim 15 is rejected under 35 U.S.C. § 103(a) as being
unpatentable over Haynor in view of Stumpe, and Hall. 5. Claim 22 is
rejected under 35 U.S.C. § 103(a) as being unpatentable over Haynor in
view of Stumpe, and Ritter.

ISSUE
Appellant contends that Stumpe does not suggest incorporating a
single magnet capable of exhibiting an asymmetric magnetic field within
the catheter of Haynor and that Acker does not supplement this failed
teaching. (Br. 6-7.)
Appellant contends that Stumpe does not suggest incorporating a
single magnet capable of exhibiting an asymmetric magnetic field within the
catheter of Haynor, and Silverstein does not supplement this failed teaching.
(Br. 7.)
Appellant contends that Stumpe does not suggest incorporating a
single magnet capable of exhibiting an asymmetric magnetic field within the
catheter of Haynor, and Hall does not supplement this failed teaching. (Br.
7-8)
Appellant contends that Stumpe does not suggest incorporating a
single magnet capable of exhibiting an asymmetric magnetic field within the

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catheter of Haynor, and Ritter does not supplement this failed teaching. (Br.
8.)
The Examiner finds that Stumpe does suggest incorporating a single
magnet capable of exhibiting an asymmetric magnetic field within
the catheter of Haynor. (Ans. 4.)
The issue is: Does the cited prior art suggest incorporating a single
magnet capable of exhibiting an asymmetric magnetic field within the
catheter of Haynor?

FINDINGS OF FACT
The Examiner finds that:
13. Haynor fails to disclose the specific types of medical devices used with
the catheter being tracked, sensors which are mounted externally to the
patient’s body, and the use of a reference catheter. (Ans. 4-5.)
14. Acker et al. disclose a tracking system for a medical intrabody probe and
teaches that it is known in the art to use such tracking system with a
mapping/ablation catheter, as well as a camera or fiber optics for imaging, or
for applying therapeutic radiation. (Ans. 5.)
15. Additionally, Acker et al. disclose magnetic sensors configured for
mounting external to a patient's body and the use of a reference catheter.
The field sensor may be a Hall effect or other similar solid state magnetic
field transducer. (Ans. 5.)
16. It would have been obvious to one of ordinary skill in the art to have
further modified Haynor in light of the teachings of Acker, as it would be
beneficial to include the position monitoring device disclosed by Haynor in a

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variety of catheter types in order to avoid exposing the patient to x-ray for
conventional probe tracking. (Ans. 5.)
17. Haynor et al. fails to disclose the use of plastic magnet material.
18. Silverstein et al. disclose a tracheal tube that uses magnets to confirm
proper placement. (Ans. 5.)
19. In Silverstein, the magnets are either solid or non-solid and may include
magnetic particles within fluid polymers or within a polymer. (Ans. 5.)
20. It would have been obvious to one of ordinary skill in the art to have
further modified Haynor et al. such that the magnet is made using a polymer
magnetic material. Such a modification involves the substitution of one
known type of material for forming a magnet for another. The polymer
magnetic material allows it to be flexible which would be advantageous for
use with a catheter being placed in the body, for example down the trachea.
(Ans. 5.)
21. Haynor et al. discloses that a variety of magnet arrangements are
possible, however, the reference fails to explicitly disclose the use of a
toroidal magnet. (Ans. 5.)
22. Hall discloses a method of magnetically navigating medical devices and
teaches the use of magnet with a toroid shape wherein the gap allows for
non-magnetic material between the poles. (Ans. 5-6.)
23. It would have been obvious to one of ordinary skill in the art to have
modified Haynor such that the magnet used is a toroidal magnet of Hall.
Such a modification involves the substitution of one well known type of
magnet in a navigation system for another and provides the advantage of
having a magnet with a stronger field. (Ans. 6.)

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24. Haynor discloses the use of an iterative process to compute the positional
information for the catheter, however, Haynor fail to disclose the use of a
table. (Ans. 6.)
25. Ritter et al. disclose a magnet tipped catheter and teaches the use of a
lookup table programmed in a computer for navigation of the catheter.
(Ans. 6.)
26. It would have been obvious to one of ordinary skill in the art to have
modified Haynor et al. Ritter to include a lookup table to compute the roll of
the catheter instead of an iterative process, as a lookup table is faster as it
takes less processing time. (Ans. 6.)
Other facts:
27. Appellant admits that Hall discloses a torroidal magnet. (Br. 7.)

ANALYSIS
Appellant contends that Stumpe does not suggest incorporating a
single magnet capable of exhibiting an asymmetric magnetic field within the
catheter of Haynor, and Acker, Silverstein, Hall and Ritter do not
supplement this failed teaching. (Br. 6-8.) Appellant further argues that
Hall does not disclose the use of a torroidal magnet to move the distal end of
a catheter and does not describe incorporation of the torroidal magnet into
the catheter. (Br. 7.)
We are not persuaded by this argument. As indicated herein, we have
found that the combination of Haynor and Stumpe describes an asymmetric
magnetic field. Appellant has not rebutted this argument. Moreover, Hall
discloses the use of a torroidal magnet to magnetically navigate a medical
device (FF 22, 27). Appellant has failed to provide evidence that one of

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ordinary skill in the art would not have found that such a substitution of a
well known type of torroidal magnet in the navigation system of Hall for that
of Haynor to provide the advantage of having a magnet with a stronger field,
would have been obvious. The rejection is affirmed.

CONCLUSION OF LAW
The obviousness rejections are affirmed.

SUMMARY
The obviousness rejections are affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

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