Book reviews

Advances in processing and pattern analysis of biological signals

Edited by Isak Gath and Gideon F. Inbar, Plenum Press, New York and London, 1996. ISBN 0-306-45214-4.

There has been rapid progress in recent years in the development of signal processing and pattern analysis methods in general and in particular in their application to biological signals.

As an update in developments in the field an international symposium was held in Israel in 1995 and this book is the result of the 27 papers presented there. Five main clinical application areas are covered, namely: the EEG, evoked potentials (EP), neuronal cell activity, the ECG, and the EMG and human movement. In each area a range of techniques is reported although some are more appropriate to the type of signal encountered. The purposes of such a meeting and consequent publication are two-fold. On the one hand leading-edge research should be reported so that it really represents an opportunity for other workers to bring themselves right up to date; on the other there needs to be a level of tutorial content adequate to enable newcomers to the particular field to get into the topic. This book succeeds fairly well on both counts.

In the former case the inevitable time delay from laboratory to bookshelf makes the contents more dated than might appear in a learned journal and so expectation should not be too high. Despite this factor the international nature of the authors enables a world view of the state of the art at the time if the conference to be presented. The range of topics included enables the reader to contrast and compare the applicability of the various techniques to the several clinical contexts. Inevitably, though, there are some gaps. For example I was disappointed to find no discussion of high-resolution ECG processing, yet heart rate variability is well represented.

As fas as tutorial value is concerned this volume succeeds rather well. The combined expertise and breadth of experience of the contributors provides a valuable insight into modern methods and applications of signal processing across a range of applied clinical disciplines. In this respect the authors also serve the reader well be providing bibliographical references for further investigation. Indeed one paper is accompanied by no less than 62 references and only three papers of the 27 included in this volume list fewer than ten. There is also a very useful index.

Overall, this book provides a useful review and discussion of recent signal processing and analysis methods in a variety of clinical settings. It should prove a worthwhile addition to any library particularly for readers new to these techniques.

Dr Michael English

Computer-integrated surgery: technology and clinical applications

MIT Press, Cambridge, Massachusetts, 1996 ISBN 0-262-20097-X, 736 pp, 596 illustrations

Surgery is always taking advantage of advances in technology, and computers are no exception. Linking the insight and knowledge of people to the precision and sensitivity of machines offers great promise to improve surgical techniques and results. This field is advancing rapidly and benefits greatly from the interaction of surgeons, engineers and scientists.

This book brings together contributors from across the spectrum of computer applications to surgery. The volume is divided into two Parts - Technology and Applications - with individual chapters being grouped into Sections. Each Section starts with an introduction from the editors and contains at least one chapter describing the problems and opportunities in a given area. Contributions range from short discussion papers to detailed presentations suitable for technical journals.

Part 1, Technology, occupies the first third of the book. It begins with three sections: Data Acquisition, Registration, and Tools for Surgical Planning. Under Data Acquisition, Mosges and Lavallee introduce sensing modalities and techniques before a series of chapters describe detailed systems for image transformation and registration. More general concepts re-emerge in the section on Surgical Planning, which includes a good introduction to three-dimensional imaging. Ergonomics and human factors are considered in a section on Human-Machine interfaces, Satava putting forward his vision for the development of virtual reality in the surgical environment. A section on Robotic Manipulators considers issues such as accuracy and repeatability in surgery. A paper looking at issues in manipulator design is followed by a detailed paper describing the use of shape-memory alloys in creating an active endoscope. In the last chapter in Part 1, Davies discusses Safety issues relevant to medical robot design.

Part 2, Applications, contains 39 chapters on particular applications of computers to surgery. The largest sections reflect where most work has been carried out: Neurosurgery, Orthopaedics and Minimal-Access surgery. There are also contributions from eye surgery; dentistry; ear, nose and throat surgery; craniofacial surgery; and radiotherapy.

Most authors describe their computer systems as 'assisting' human operators. However, the use of the word 'assist' covers a range of approach. Enhancement of human abilities by computer-controlled devices (eg voice-controlled endoscopes, computer-assisted navigation systems) appears most commonly where operations are more uncertain or carried out at a small scale (such as in the middle ear). Operative procedures that are well-defined (though complex or requiring high precision or dexterity) allow the application of systems where the human operator sets up the patient, programmes the operation, and allows the computer to take control (although under final surgical veto).

Cutting applications in orthopaedics are the most advanced in this regard, since bone is (relatively) rigid. Craniofacial surgery is increasingly relying on computerised planning and execution to achieve a good outcome - the face being one area where the results of surgery are displayed for all to see.

The clinical papers consider registration and localisation problems in most fields, including therapy (assisting radiotherapy, and the design and fabrication of dental restorations). Also touched on is the idea of computer-assisted diagnosis through improved imaging and expert systems (in both dental radiography and the monitoring of glaucoma).

Colour plates from various papers are included,which particularly aids understanding of image manipulation and processing.

The editors of this book have undertaken the ambitious task of covering the whole field of computer applications to surgery. Given the pace at which this field is moving, it may well be the last such book to be contained in one volume. What they have produced catches the excitement of being involved in one of medicine's frontiers. It provides an introduction to the field for new graduates, and established engineers and surgeons will find ideas to stimulate and challenge.

One thing that becomes clear from reading the book is that humans are not fully ready to entrust either diagnosis or therapy to machines. That will require not only additional technical advances, but also a shift in cultural perception. The editors feel confident it will happen - are you?

Keith Ison