Friday, September 26, 2008

Inside Story: Physics in Medicine

The Institute of Physics has an excellent website called "Inside Story: Physics in Medicine", which contains some fascinating animations with colorful images. It is at a significantly more elementary level than the 4th Edition of Intermediate Physics for Medicine and Biology, but might be used as a fun "extra" in a medical physics class based on that book. MRI Scans, Colonoscopy, PET Scans, and Radiotherapy are the featured topics.

When you first link to the webpage, you have two choices. If your computer has Macromedia Flash Plugin 7, then definitely enter the "flash" site, as it is much more interesting than the "html" site.

"Inside Story" was produced by the Institute of Physics and the Medical Research Council, a English organization that "promotes the balanced development of medical and related biological research in the UK." It was developed as part of the 2005 Einstein Year, a worldwide celebration of the one hundredth aniversary of Einstein's miraculous year, when Albert Einstein, at age 26, published his theories of Brownian motion, special relativity and the photoelectric effect.

Friday, September 19, 2008

Virtual Colonoscopy

Ever had a colonoscopy? It's not pleasant. A paper published this week in the New England Journal of Medicine (Volume 359, pages 1207-1217), titled "Accuracy of CT Colonography for Detection of Large Adenomas and Cancers" suggests an alternative to the traditional procedure for detecting colorectal cancer: a "virtual colonoscopy". This X-ray technology uses Computed Tomography (CT), which Russ Hobbie and I discuss in Chapter 12 of the 4th Edition of Intermediate Physics for Medicine and Biology. The NEJM article concludes that "in this study of asymptomatic adults, CT colonographic screening identified 90% of subjects with adenomas or cancers measuring 10 mm or more in diameter. These findings augment published data on the role of CT colonography in screening patients with an average risk of colorectal cancer." To learn more about this study, see the Associated Press article by Mike Strobbe, and an article in US News & World Report.

Any X-ray procedure does have a risk associated with the radiation dose. A typical virtual colonsocopy has a dose of 5 to 10 mSv. By comparison, the yearly dose from the natural background radiation is about 3 mSv. (The sievert is a unit of dose equal to a Joule per kilogram, adjusted for its biological effectiveness. A mSv is one thousandth of a sievert.) See my December 7, 2007 entry in this blog, or Chapter 16 of the 4th Edition of Intermediate Physics for Medicine and Biology, for more information about radiation safety and CT scans. Of course, any risk of radiation must be weighed against risks involved with traditional colonoscopy procedures.

Now for the bad news: You still need to "clean out your bowels" before the procedure, regardless of which method you use: traditional or virtual.

Saturday, September 13, 2008

Particle Physics Rap

Today's post (a rare non-Friday message) has nothing to do with the 4th Edition of Intermediate Physics for Medicine and Biology, and nothing to do with medicine and biology at all. But if you are a physics fan, you must check out the particle physics rap at (see the video highlight). This rap celebrates the Large Hadron Collider (LHC), which was turned on September 10, beginning what may be some of the greatest particle physics experiments ever. The rap is too delightful to miss. Enjoy.

Note added October 26: Physics central took the blog off their site, but you can still find it at youtube:

Friday, September 12, 2008

Switching from Physics to Biology

Physicists studying from the 4th Edition of Intermediate Physics for Medicine and Biology may be interested in entering the field of biological physics. If so, I suggest reading "Switching from physics to biology: Physicists in transition help shape biological theory" by Jennifer Ouellette (The Industrial Physicist, 9: 20-23, 2003). The article, which can be found online, begins

"Many in physics chafe at the oft-quoted maxim that the 21st century is the 'age of biology.' Others see the biological boom as offering unique opportunities for physicists—and not just in the traditional area of building instrumentation for experimental research. Physicists are well positioned by their training to contribute to the development of a theoretical framework in biology, a field that has matured to the point where sufficient quantitative data and sophisticated experimental tools exist to test biological theories."

For other physics-to-biology stories, see Yuh-Nung Jan's interview in "Current Biology" and Chris Sander's story told on the Sloan-Kettering Institute website. Also, here is some advice from the "Grant Doctor" published in Science.

Friday, September 5, 2008


While surfing the internet one evening, I stumbled upon a fascinating website that will interest readers of the 4th Edition of Intermediate Physics for Medicine and Biology. It is called "Biocurious, a biophysics blog".

"Biocurious is a weblog about biology (and physics, grad school, and miscellenaeous other things!) through the eyes of physicists."

As best I can tell, Biocurious is maintained entirely by two graduate students, Andre Brown of the University of Pennsylvania and Philip Johnson of the University of Toronto. The blog is interesting, well-written, and provides insight into the interface between physics and biology, as well as the lifestyle of biological physics grad students. One enjoyable feature of this site is the "molecule of the month" (from the protein data bank), and another is the extended list of other related blogs, which I have only begun to explore. I particularly like their header image, a picture by David Goodsell of a macrophage and bacterium at a magnification of 2,000,000.

Nice blog, Andre and Philip.