Tuesday, 19 October 2010

T 266/07 – A Questionable Springboard

In the preceding post we have seen how the Board came to the conclusion that claim 1 of the sole request on file was not excluded from patentability under A 53(c). The claim having been found to be novel, the Board now considers whether it fulfills the requirements of A 56 (inventive step). The passage dealing with the question of whether document D1 is a suitable closest prior art is not without interest:

[6.1] In general terms, D1 discloses a two-dimensional MRI method in which a projection reconstruction technique is employed. In D1, two types of image are created. In order to monitor the imaging process, a series of intermediate “rough” images are produced. These rough images are acquired from undersampled k-space data sets, each of which is derived from different, interleaved radial projection views, the number of radial projection views for each rough image being less than the number required for fully-sampled k-space. These rough images can be displayed individually and employed in their own right to monitor any time-lapse variation of the slice being imaged. The “final” image, which corresponds to fully-sampled k-space, is produced by combining all of the interleaved data sets. However, it is the method of producing the “rough” images which the Board considers to represent the closest prior art.

[6.2] The method of claim 1 is distinguished from the method of producing the rough images in D1 at least in the following respects:
(a) No reference is made in D1 to the application of a phase encoding gradient along a first axis or indeed to the repetition of the pulse sequence with a set of different phase encoding gradient values and the Fourier reconstruction of a 3D volume image of the entire field of view from the sparsely sampled k-space data set.
(b) No reference is made in D1 to the mask subtraction step.
(c) No specific reference is made in D1 to the production of an angiogram. Whether D1 may be considered to disclose the use of a contrast agent in combination with MRI was the subject of some debate. However, as will become apparent in the following, this point is in fact purely academic and so can be left open.

[6.3] Each of the above-identified differences gives rise to a different technical effect. In particular, the technical effect of difference (a) is that three dimensional imaging is achieved: positional information in the third dimension is obtained by the phase encoding. The technical effect of difference (b) is that the quality of the final image is improved by removing the artifacts. The technical effect of difference (c) is that a specific organ, namely the vasculature, is imaged.

These technical effects represent an aggregation of isolated effects which have no interdependence. When assessing inventive step, each of the above-identified differences may therefore be considered separately; for the subject-matter of the claim to be considered inventive, it suffices to show that just one of these differences is not obvious (T 345/90 [5] and T 701/91 [6.4-5]).

Since the Board considers that it is not obvious to combine the method of producing the rough images of D1 with phase-encoding and Fourier reconstruction in the third dimension, the question of whether differences (b) and (c) involve an inventive step – and indeed the question of whether D1 discloses the use of a contrast agent in combination with MRI – may be left open.

[6.4] Although D1 is the one document which appears to contain the largest number of relevant technical features in common with claim 1, the Board considers that D1 does not actually represent a suitable starting point for an attack on inventive step. In particular, when applying the problem-solution approach, the objective problem which is formulated must be one which the skilled person would realistically consider addressing when setting out from the starting point.

A conscious choice of starting point, made in the knowledge of the respective benefits and drawbacks of the various prior art disclosures, not only determines the subject-matter serving as a starting point but also defines the framework for further development (T 439/92 [6.2.4]). Taking the disclosure of D1 as the starting point, the skilled person cannot ignore the fact that the very reason for resorting to the rough images in D1 is to enable fast image acquisition: it is in order to achieve rapid imaging that the quality of the intermediate images is willingly sacrificed. The speed of imaging is consequently an inseparable part of the disclosure of D1 and defines that framework within which any further development of the imaging method of D1 must be carried out. In view of this context, the Board is of the opinion that the construction of any argument which involves the development of the imaging method of D1 in a manner which would compromise the speed of imaging would be counter-intuitive and can only be seen as the result of an ex-post facto analysis. Although it may be argued that the combination of two-dimensional PR imaging of D1 with phase encoding and Fourier reconstruction along the z-direction may present the most obvious way in which to obtain 3D images from the 2D PR images of D1, the speed of imaging is of such fundamental importance in D1 that the skilled person starting from D1 would not forfeit this aspect.

[6.5] The examining division (ED) argued that there was an obvious desire to extend the technique of D1 to the acquisition of 3D data.

The Board does not agree. In view of the fast-imaging framework of D1, the Board agrees with the appellant that the inevitable delay involved in the processing time when employing phase encoding along the z-axis is so contrary to the declared aim of D1 that the skilled person would simply not consider adapting the method of producing the rough images in D1 to include phase encoding and Fourier reconstruction in the third dimension. Starting from D1, an “obvious desire” to extend to 3D imaging cannot therefore be recognised.

[6.6] The ED further argued that the purpose of the technique of D1 was to obtain an early indication of any problems which may have arisen during the imaging and which may corrupt the final image such that they can be corrected as soon as possible. If the final image is to be a 3D image, then the rough, early warning images must also contain 3D information.

The Board agrees that, in principle, it may be desirable to provide intermediate 3D images during a 3D scan. However, this implies starting from a 3D imaging method and developing it to provide intermediate images. This approach will be discussed in relation to D4 below.

[6.7] The Board is therefore of the opinion that starting from D1, the skilled person would not consider it obvious to adopt the combination of 2D PR rough imaging with phase encoding and Fourier reconstruction in the third dimension. Starting from D1, the subject-matter of claim 1 is therefore not obvious.

Should you wish to download the whole decision, just click here.


Myshkin said...

I haven't read D1, but the fact that D1 is concerned with speed doesn't seem a convincing reason to me why an extension from the 2D data acquisition of D1 to 3D data acquisition would not be an obvious desire.

Speed is almost always an important concern for the skilled person. Does that mean that the skilled person would generally not wish to add further functionality? Certainly not.

As far as I understand, the features of D1 that achieve the speed are not affected by the distinguishing features achieving the extension from 2D to 3D. The resulting method still achieves speed in the same manner as D1. In a sense this is a case of partial problems (increased speed, extension from 2D to 3D), except that D1 already solves one of the problems (increased speed).

I'm not sure why the "declared aim of D1" (pt. 6.5) should matter at all. Would the outcome have been different if the method of D1 had not been found in document D1, but in some disclosure that gave no information on the aim of the method's inventor?

Once it is accepted that an extension to 3D data acquisition is an obvious desire, the Board's reasoning in pt. 6.6 no longer holds, either.

Just my personal opinion, of course...

Anonymous said...

In order to avoid hindsight, "declared aim" should be accounted for. Sometimes Examiners come up with modifications of the prior art that rely heavily on Applicant's teachings, but re-characterize those teachings as knowledge commonly known in the art. Perhaps this decision overly-relied on the context of D1, but it easy to imagine scenarios where an Examiner modifies the primary reference in such a way that the entire point of the invention is missing. Thus, I welcome the underlying principles of this decision (i.e., framework of the prior art) with open arms.

In the US, if a proposed modification would render the prior art invention being modified unsatisfactory for its intended purpose, then there is no suggestion or motivation to make the proposed modification. In re Gordon, 733 F.2d 900, 221 USPQ 1125 (Fed. Cir. 1984); MPEP 2143.01 (V).

Myshkin said...

But is the point of D1 of any relevance? The fact is that the method or apparatus disclosed by D1 is part of the prior art. In my view, this prior art method or apparatus including all its inherent features should be considered on its own, independent of any intentions that the author of D1 may have had but which are not "visible" when studying the method or apparatus per se.

What if an opponent could provide evidence that a method having the same features as the method of D1 had been performed in public before the priority date. No intended purpose is known from this prior use disclosure. Could the inventive step attack have worked starting from this prior use disclosure, whereas it did not work starting from the disclosure found in D1?

Of course intentions may be important for a proper interpretation of D1! And certainly the claims on file should not influence the interpretation of D1.

Maybe a somewhat similar issue: a technical prejudice must be a widely held belief in the field at the priority date. Merelz a negative statement in D1 is not sufficient.

Anonymous said...

I am not defending this decision; I merely agree with the underlying rationals, not its application. That said,

"In my view, this prior art method or apparatus including all its inherent features should be considered on its own, independent of any intentions that the author of D1 may have had but which are not 'visible' when studying the method or apparatus per se."

I find this distinction artificial and susceptible to hindsight reasoning. For example, is this how one skilled in the art would read a reference? I think not. They would read the whole thing, including intended and best uses. A reference should be used as a whole. After all, we are trying to answer the question what would one skilled in the art do (or would not do) in light of the teachings of the prior art.

Of course, the document is also judged in light of knowledge generally possessed by one in the art (that's why tech. prejudice shouldn't be established by a single reference). Thus, I am not advocating intended use be the end-all-be-all of interpreting a reference, but it should be relevant. And, to poorly address your biggest problem with this decision, I believe there is a difference between a reference that states an intended use and one that does not. Does it mean "intended use" always controls? No, but it should be another weight on the scales of an obviousness decision. How much it matters, of course, depends on context.