Wow, it’s been a year since the Columbia space shuttle broke up on re-entry. I remember waking up that Sunday morning, turning on the news and seeing the first reports happening live during coverage of what was supposed to be the landing. I remember seeing footage of the shuttle, a bright light streaking across the sky with smaller lights falling from it, and thinking “Gee, that doesn’t look right”. And then learning that it really wasn’t right, hearing people saying that the shuttle had broken up. And then the days and months afterward, learning about the cause, about what happened and the reasons behind the tragedy. It seemed to me that many of the problems cited were very similar to what was supposed to have been learned from the Challenger accident.
Lots of people say the Space Shuttles are outdated and that something new is needed. But perhaps what’s really needed is a change in the management structure and culture at NASA.
Interview day
Today’s the day. The day of my wife’s med school interview. At this very moment, she’s probably somewhere being interviewed by a doctor, or med student trying to learn more about her and why she wants to be a doctor. I think she’ll do fine, and I think she’ll impress them enough to get in. She’s been working hard for this, and she’s been working hard to get prepared all week. With any luck, in a couple of weeks or so, I should find out if I’m married to a prospective doctor or not.
Body Challenge Week 3
Ok, week three is over, and I’m afraid I haven’t really made much progress into starting my exercise routine. None at all really. But I’ve managed to maintain 172 lbs (78 kg) at least. Still walking and climbing stairs wherever I go.
Friday Five
You have just won one million dollars:
1. Who do you call first?
Probably my wife, unless she was there with me when I win. Then I might call my sister or brother.
2. What is the first thing you buy for yourself?
The complete Babylon 5 series, Stargate SG1 series, and the Star Trek film series, all on DVD. And maybe a Trek 2300 with all the accessories.
3. What is the first thing you buy for someone else?
Probably the horse and Nissan Titan my wife wants.
4. Do you give any away? If yes, to whom?
Set up some scholarships for physics students at University of Alberta and donations to the Canadian Diabetes Association and American Diabetes Association.
5. Do you invest any? If so, how?
I think I’d sock away about half of it in various investments. I’d have to find a financial advisor to consult with, someone who came highly recommended by someone I trust.
Journal Club: Optimization of Ga-67 Imaging
Nuclear medicine is one of the areas I specialize in, so this week’s article is in that area. El Fakhri G, Moore SC, Kijewski MF, “Optimization of Ga-67 imaging for detection and estimation tasks: Dependence of imaging performance on spectral acquisition parameters“, Med Phys 29, 1859-1866 (2002).
Ga-67 is commonly used for tumour imaging, localization and staging. It has three photopeaks, 93, 185 and 300 keV, although commonly only the 93 and 185 keV photopeaks are used for imaging. This article examines ways to optimize the energy windows to maximize SNR and to take advantage of all three photopeaks.
Abstract:
We have compared the use of two (93 and 185 keV) and three (93, 185, and 300 keV) photopeaks for Ga-67 tumor imaging and optimized the placement of each energy window. Methods: The bases for optimization and evaluation were ideal and Bayesian signal-to-noise ratios (SNR) for the detection of spheres embedded in a realistic anthropomorphic digital torso phantom and ideal SNR for the estimation of their size and activity concentration. Seven spheres of radii ranging from 1 to 3 cm, located at several sites in the torso, were simulated using a realistic Monte Carlo program. We also calculated the ideal SNR for the detection from simple phantom acquisitions. Results: For detection and estimation tasks, the optimum windows were identical for all sphere sizes and locations. For the 93 keV photopeak, the optimal window was 84-102 keV for the detection and 87-102 keV for estimation; these windows are narrower than the 20% window often used in the clinic (83-101 keV). For the 185 keV photopeak, the optimal window was 170-220 keV for the detection and 170-215 keV for estimation; these are substantially different than the 15% window used in our clinic (171-199 keV). For the 300 keV photopeak, the optimal window for detection was 270-320 keV, and for estimation, 280-320 keV. Using the three optimized, rather than only the two lower-energy, windows yielded a 9% increase in the SNR for the detection of the 3 cm diam sphere (a 12% increase for a 2 cm diam sphere) and a 7% increase in the SNR for estimation of its size. For the acquired phantom data, detection also increased by 9%-12% when using three, rather than two, energy windows. © 2002 American Association of Physicists in Medicine.