Friday, December 28, 2007

Top Ten Biological Physics Books

Each year at this time, we are bombarded by top ten lists, such as “Top Ten News Stories of 2007” or “Top Ten Movies of the Year.” Russ Hobbie and I cite many excellent books in the 4th edition of Intermediate Physics for Medicine and Biology. Below I list ten of my favorites. Other good books are cited in the November 23 entry of my blog.
Random Walks in Biology Howard Berg, 1983, Princeton University Press. This book is simply the best introduction to the role that diffusion plays in biology.

Air and Water Mark Denny, 1993, Princeton University Press. A wonderful book that covers some of the same topics we discuss in our first 10 chapters. It approaches the material from the point of view of a physiologist with some knowledge of physics, compared to our approach as physicists with some knowledge of physiology.

Machines in Our Hearts: The Cardiac Pacemaker, the Implantable Defibrillator, and American Health Care Kirk Jeffrey, 2001, Johns Hopkins University Press. More of a history book than an engineering book, it tells the fascinating story of how pacemakers and defibrillators were developed.

 Electric Fields of the Brain: The Neurophysics of EEG Paul Nunez and Ramesh Srinivasan, 2005, Oxford University Press. The electroencephalogram from a physicists point of view.

Electricity and Magnetism Edward Purcell, 1985, Berkeley Physics Course, Vol. 2, McGraw Hill. Other E and M books may be more comprehensive (for example Griffiths or Jackson), but when I’m looking for insight I go to Purcell.

Statistical Physics Frederick Reif, 1964, Berkeley Physics Course, Vol. 5, McGraw Hill. I admire Reifs statistical approach to thermodynamics. Much of Chapter 3 in our book follows the same path as Reif. It is a great choice for those looking for an introduction to statistical mechanics.
Div, Grad, Curl, and All That, by H. M. Schey, superimposed on Intermediate Physics for Medicine and Biology.
Div, Grad, Curl, and All That: An Informal Text on Vector Calculus H. M. Schey, 2005, Norton. A gentle introduction to vector calculus. Much more intuitive than other math books I know of.

Scaling: Why is Animal Size so Important? Knut Schmidt-Nielsen, 1984, Cambridge University Press. A delightful discussion of how physics and physiology conspire to constrain how large animals can become. See also his book How Animals Work.

Life in Moving Fluids Steven Vogel, 1992, Oxford University Press. One of the best introductions to biological fluid dynamics that I know. Vogel has many other fascinating books, including Vital Circuits about the circulatory system.


When Time Breaks Down Arthur Winfree, 1987, Princeton University Press. A book that had a huge influence on my own research on the electrical behavior of the heart. See also his book The Geometry of Biological Time, especially the second edition that contains updated information on cardiac electrophysiology.

Friday, December 21, 2007

Should the Premed Requirements in Physics be Changed?

Nearly 30 years ago, Abraham Liboff and Michael Chopp—both faculty members at Oakland University—published an article in the American Journal of Physics titled “Should the Premed Requirements in Physics be Changed?” (Volume 47, Pages 331–336, 1979). Their conclusions are still relevant today, and eloquently confirm the purpose of Intermediate Physics for Medicine and Biology. Abe and Mike concluded
The reasons usually given for including the physics component in the premedical curriculum include its importance in a liberal arts education, and the use of physics grades as a screening yardstick for admissions committees. However, educators have ignored the wide range of applications of physics to medicine in diverse areas such as physiology, problem solving, quantitation, diagnostic techniques, etc.

Most premeds take physics too late in their undergraduate program to accommodate physics electives. In medical school there is no tradition of specialized physics, as occurs in chemistry and biology. The net result is that medical students are disadvantaged in physics, unable to cope with advances in technology requiring a stronger base than the usual ten hours of undergraduate physics.

The new MCAT examination perhaps signals a change in thinking by the medical community, in that the test goes for towards recognizing the essential role that physics plays in modern medicine. Not only is knowledge of each of the sciences required, but, equally important, problem-solving and quantitative skills are tested, reflecting the sort of techniques emphasized in physics.

To directly address the question of the poor undergraduate physics preparation of future physicians and other health care professionals, we suggest that at least one, and probably, two, semesters of additional physics be added to all premedical programs. This added work should be specialized material in the physics of medicine and should require both a year of calculus and a year of introductory physics as prerequisites.

Friday, December 14, 2007

Technetium Shortage

The shutdown of a nuclear reactor at Chalk River, Ontario has caused a shortage of an isotope of technetium (Tc-99m) used for medical imaging (see the New York Times article for details). What is technetium, and how is it produced? The following is a quote from the 4th edition of Intermediate Physics for Medicine and Biology (page 497).
The most widely used isotope [for medical imaging] is Tc-99m. As its name suggests, it does not occur naturally on earth, since it has no stable isotopes. We consider it in some detail to show how an isotope is actually used... The isotope is produced in the hospital from the decay of its parent, Mo-99 [molybdenum], which is a fission product of U-235 and can be separated from about 75 other fission products. The Mo-99 decays to Tc-99m.

Technetium is made available to hospitals through a “generator” that was developed at Brookhaven National Laboratories in 1957 and is easily shipped. Isotope Mo-99, which has a half-life of 67 h, is adsorbed on an alumina substrate... As the Mo-99 decays, it becomes pertechnetate (TcO4-). Sterile isotonic eluting solution is introduced under pressure above the alumina and passes through after filtration into an evacuated eluate container. After removal of the technetium, the continued decay of Mo-99 causes the Tc-99m concentration to build up again. A generator lasts about a week.

Friday, December 7, 2007

Is Computed Tomography Safe?

Drs. David Brenner and Eric Hall recently warned that the increased popularity of CT scans, particularly in children, can lead to an increased incidence of cancer (“Computed Tomography – An Increasing Source of Radiation Exposure,” New England Journal of Medicine, Volume 357, Pages 2277–2284, 2007). Widespread awareness of this research may lead to the avoidance of unnecessary CT examinations. (This conclusion remains controversial, see statements by the American Association of Physicists in Medicine and the Radiological Society of North America.) Brenner and Hall's earlier work on this issue is discussed in the 4th edition of Intermediate Physics for Medicine and Biology (page 472).