There it is, looming off the eastern coast of the Yucutan penninsula. TD 20 came while I was busy learning more PET stuff. So which one becomes Stan first, 19 or 20. 19 is still heading into the mid-Atlantic, and 20 looks to be heading across the Gulf into central Mexico. NHC forecasts call for TD 19 not developing into much, but TD 20 might get stronger once it gets into the Gulf. Which one becomes Stan, and which one becomes Wilma? Anybody want to put a pool together?
It's SuperNala!
A Drs. Foster & Smith catalog mysteriously appeared in our mail box a few weeks ago. With Hallowe'en coming, the wife decided the Superman costume was too cute to pass up and decided we needed to go Hallowe'en'ing with the dog. So here's Nala all dressed up in her Hallowe'en costume. Fit needs to be adjusted a little bit, and she's planning to get some red cloth to make a skirt out of (Nala is a girl after all).
Of course, all this has led to the wife wanting to plan a dog Howlowe'en party for some of our dog owning friends and maybe even dog owning neighbours.
There's even a pumpkin by the front door waiting to be carved into a jack-o-lantern.
This morning when I woke up, they were just talking about the system in the Bahamas potentially becoming a tropical depression. I get out of the shower and it gets turned into TS Tammy with a center just off the coast of Florida. Good grief.
Fortunately, it's not forecast to have much time to get any stronger than a tropical storm, so I expect the rest of the week to be breezy and rainy.
From today's 0730 discussion:
TROPICAL STORM TAMMY IS MOVING FAIRLY RAPIDLY TOWARD THE NORTH-NORTHWEST...WITH ESTIMATED INITIAL MOTION OF 335/14 BASED PRIMARILY ON RADAR FIXES. THE STEERING IS BEING PROVIDED BY THE SOUTHERLY FLOW IN BETWEEN A DEVELOPING MID/UPPER LEVEL LOW IN THE EASTERN GULF OF MEXICO AND A RIDGE OVER THE WESTERN ATLANTIC. THE DYNAMICAL MODELS FORECAST THE LOW OVER THE GULF TO DEEPEN SOMEWHAT WHILE THE RIDGE OVER THE MID-ATLANTIC COAST MOVES OFFSHORE. THEREFORE... ONLY A SUBTLE BEND TO THE WEST IN THE HEADING DURING THE NEXT COUPLE OF DAYS IS FORECAST... WITH A GRADUAL DECREASE IN FORWARD SPEED. DUE TO THE ANGLE OF APPROACH OF THE CENTER OF TAMMY TO THE COASTLINE... IT IS DIFFICULT TO SPECIFY THE LANDFALL TIME OR LOCATION OF THE CENTER. HOWEVER... IT IS MORE IMPORTANT TO FOCUS ON THE LARGE AREA OF WINDS AND CONVECTION TO THE NORTH AND EAST OF THE CENTER... WHICH NECESSITATES A TROPICAL STORM WARNING FOR A LONG STRETCH OF COASTLINE. SINCE TAMMY IS UNDER MODERATE SOUTHERLY SHEAR... ONLY SLIGHT STRENGTHENING APPEARS LIKELY... AND THE ASYMMETRIC CLOUD PATTERN WILL PROBABLY PERSIST.
How does a Sun Ultra 10 box compare with a dual Pentium II 450 box in terms of performance? We've been looking to replace this server for some time now, but since there is never any budget for this kind of thing, I've been relegated to scavenging hand-me down servers. One possibility is to take a Dell PowerEdge 6300 with dual P II Xeon 450s and see if I can turn it into a quad processor unit with the CPUs from this box. Another possibility replace this server with a Sun Ultra 10. I wonder if I can install Fedora on an Ultra 10...
Nope, x86 and PowerPC only...looks like I'll be stuck with Solaris. I wonder how well Solaris 10 runs on an Ultra 10. Maybe if I'm lucky I'll be able to scavenge enough parts to beef it up some.
According to Distributed.net's speed pages, a dual P II 450 will crunch RC5-72 keys at 1,825,164.00 keys/s (I think that's probably this machine...). A dual UltraSPARC II 400 MHz does 1,134,165.67 keys/s.
Maybe I should try to set up the quad PII box...What I really need to do is scrounge up a better machine.
The NHC is calling this subtropical depression 22
SUBTROPICAL INSTEAD OF TROPICAL DUE TO THE INTERACTION WITH A LARGE-MID/UPPER LEVEL LOW SOUTH OF THE CYCLONE.
Forecast has it reaching tropical storm in a couple of days, but looks like it will be staying out in the ocean and heading to the northeast US. After all the rain they've had this weekend, they might get another drenching next weekend.
From today's 5PM discussion:
THE DEPRESSION REMAINS IN DEEP-LAYER EASTERLY FLOW NORTH OF THE MID/UPPER-LEVEL LOW WITH ABOUT 15 KT OF SHEAR. THE SHIPS MODEL SUGGESTS THAT THE SYSTEM WILL UNDERGO PULSES OF SHEAR DURING THE NEXT THREE DAYS...AND THEN UNDERGO SIGNIFICANT SHEAR AFTER THREE DAYS. THE GFDL AND THE LARGE-SCALE MODELS ALL LOSE THE SYSTEM IN 36-72 HR. ALL OF THIS...COMBINED WITH SEA SURFACE TEMPERATURES OF 26C-27C ALONG THE FORECAST TRACK...SUGGEST THE CYCLONE COULD STRUGGLE TO INTENSIFY. THE INTENSITY FORECAST CALLS FOR MODEST STRENGTHENING A LITTLE ABOVE THAT OF THE SHIPS MODEL... WITH A PEAK INTENSITY OF 50 KT IN 48 KT. THE NEW INTENSITY FORECAST CALLS FOR A FASTER WEAKENING AFTER 72 HR THAN THE PREVIOUS PACKAGE. IF THE LARGE-SCALE MODELS ARE CORRECT ON THE FORMATION OF THE SECOND LOW...OR IF THE SHIPS MODEL IS RIGHT ABOUT THE SHEAR... THE CYCLONE COULD WEAKEN EVEN FASTER. THERE IS STILL A CHANCE THE SYSTEM COULD FULLY TRANSITION TO A TROPICAL CYCLONE DURING THE NEXT 36-48 HR.
Waaaay out in the eastern Atlantic sits TS Vince. Definitely not going to be a bother unless you live in Portugal or Spain. Just over a month and a half left in this year's season, and Wilma is the last name left before NHC starts digging into the greek alphabet. Will we reach that record setting Alpha2005? Stay tuned and find out...
I think I'll take out some of those frozen turkey bits from my grilled turkey and have them for dinner tonight.
NHL hockey is back, and now I can watch it on OLN now, instead of hoping for the smattering of games on ESPN. Better play by play commentary too. It's no Hockey Night in Canada, but it'll do. Now if only they could show more than two games a week...
This year there are a few new rules that I'm trying to decide if I like. The new shoot-out rule for tie games I think will make things interesting. I've always found shootouts to be exciting. Personally I'd like to see the NHL go to the wider rink size used in international hockey. I think the wider rink makes for more interesting play.
Every now and then, I'll spot a bot hitting the server looking for an installation of phpMyAdmin. Presumably it's looking for a version to exploit or one that can be used to swipe data from. They typically come as a burst of requests trying to find it in some variation of commonly used folders.
Today though was the first day I spotted a bot that actually specified a user-agent in it's HTTP request. Isn't that kind of like a burgular wearing a bright red shirt that has 'THIEF' written on it?
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:54 -0400] "GET /PMA/main.php HTTP/1.0" 404 4998 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:54 -0400] "GET /phpmyadmin/main.php HTTP/1.0" 404 5005 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:55 -0400] "GET /mysql/main.php HTTP/1.0" 404 5000 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:55 -0400] "GET /admin/main.php HTTP/1.0" 404 5000 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:56 -0400] "GET /db/main.php HTTP/1.0" 404 4997 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:56 -0400] "GET /dbadmin/main.php HTTP/1.0" 404 5002 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:56 -0400] "GET /web/phpMyAdmin/main.php HTTP/1.0" 404 5009 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:56 -0400] "GET /admin/pma/main.php HTTP/1.0" 404 5004 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:57 -0400] "GET /admin/phpmyadmin/main.php HTTP/1.0" 404 5011 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:57 -0400] "GET /admin/mysql/main.php HTTP/1.0" 404 5006 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:57 -0400] "GET /mysql-admin/main.php HTTP/1.0" 404 5006 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:57 -0400] "GET /phpmyadmin2/main.php HTTP/1.0" 404 5006 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:58 -0400] "GET /mysqladmin/main.php HTTP/1.0" 404 5005 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:58 -0400] "GET /mysql-admin/main.php HTTP/1.0" 404 5006 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:59 -0400] "GET /main.php HTTP/1.0" 404 4994 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:19:59 -0400] "GET /phpMyAdmin-2.5.4/main.php HTTP/1.0" 404 5011 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:20:00 -0400] "GET /phpMyAdmin-2.5.1/main.php HTTP/1.0" 404 5011 "-" "PMAFind"
h-69-3-143-228.nycmny83.covad.net - - [11/Oct/2005:08:20:08 -0400] "GET /phpMyAdmin-2.5.6/main.php HTTP/1.0" 404 5011 "-" "PMAFind"
This bot didn't just hit my server once...it visited three times in the same day...from the same address.
Not much useful in Google about this beast. Just a couple of posts. The rest of Google's results are just webserver usage statistics showing hits by the bot.
Just an entry to remind myself where to find the newest PACS® (Physics and Astronomy Classification Scheme®).
Biological and medical physics is category 87. The medical imaging categories go from 87.57 to 87.63.
Some people look at doing literature searches as a chore. Me, I think it's fun.
My typical project protocol normally goes like this:
Step 6 is the fun literature search, because it means trips to the library. I usually find everything I need using PubMed, although sometimes it takes a while to find the right search terms to use. Get a collection of abstracts, highlight the ones I want to get and it's off to the library to dig out dusty old journal volumes for the paper I'm looking for. When I'm done, it's always fun to browse through the journals to see what interesting articles were being published at the time. That's my favourite part of the literature search. Now and then I'll even stumble onto a bonus article that I need to copy. You'd be surprised at how much interesting reading you can find in a 10 or 20 year old journal volume. Usually it's mostly from a historical perspective, but sometimes there's that long forgotten article that just happens to have exactly what you're looking for and didn't show up in the literature search.
I have a mild obsession with time...more specifically, making sure my clocks are accurate and tell me the right time. I think it comes from going to schools and jobs where every single clock read a slightly different time. You could look at 10 different clocks, and get 10 different times. It always drove me nuts.
All the computers I use have some form of time synchronization software to get a reasonably accurate time from one of my servers, which in turn is synchronized daily with a Stratum 2 time server. I have two clocks that synchronize with the NIST time signal broadcast from Fort Collins, CO. They don't display seconds though. The other clocks get synchronized to the computer as does my watch.
I've been pushing to have time synchronization software enabled or installed on the imaging equipment too, to make sure the images and studies get accurate time stamps (some medico-legal reasons for this). They can be notoriously bad for having inaccurate time. Once I found an control console that was off by several days. Hasn't been all that easy though. Most vendors are always a little bit suspicious about software they don't know about, even if it's something that's already on the system, and it's always the first to get blamed if something goes wrong.
While I was out for the weekend, TS Wilma formed in the Carribbean this morning out of TD 24. Wilma's not moving very fast at the moment, and still probably a week or so at least before there's any reliable indication of where in the Gulf it's going to go. Just the fact that Wilma's heading into the Gulf seems to be enough to set off the oil speculators though.
No more names left in the 2005 hurrcane names list. With 6 weeks left in the official season, I wouldn't be at all surprised now to see this year become a record setter with Alpha2005 before the end of November.
From this morning's 5 AM NHC discussion:
THE INITIAL MOTION IS AN UNCERTAIN 235/03. THE GENERAL TREND IN THE CONVECTIVE CLOUD PATTERN HAS BEEN TO SHIFT SLOWLY SOUTH OR SOUTHWESTWARD AS MID-LEVEL RIDGING TO THE NORTH OVER FLORIDA AND CUBA APPEAR TO BE THE ONLY STEERING FLOW AVAILABLE. BUT ON A LARGER SCALE... WILMA REMAINS TRAPPED BETWEEN TO HIGH PRESSURE CELLS TO THE NORTHWEST AND EAST OF THE CYCLONE. THE 00Z GLOBAL MODELS AND THE MAJORITY OF THE NHC MODEL GUIDANCE HAS SHIFTED SIGNIFICANTLY WESTWARD OR TO THE LEFT OF THE PREVIOUS GUIDANCE AND FORECAST TRACK. THE ONLY MODELS NOT CLOSE TO THE NHC CONSENSUS OR GUNA MODEL ARE THE ECMWF... CANADIAN... AND THE GFS 10-MEMBER ENSEMBLE MODELS. THE ECWMF HAS BEEN REMARKABLY CONSISTENT WITH ITS TRACK THE PAST 5 DAYS IN MOVING THE CYCLONE TOWARD THE YUCATAN CHANNEL. IT ALSO WAS THE ONLY MODEL TO EARLY AND ACCURATELY PREDICT CYCLOGENESIS. THE ECMWF AND THE CANADIAN MODELS ARE ALSO THE ONLY MODELS THAT DO NOT LOSE THE SHORTWAVE TROUGH LOCATED OVER THE CENTRAL U.S. THAT IS CURRENTLY MOVING EASTWARD THROUGH THE AXIS OF THE LONGWAVE RIDGE. UPPER-AIR DATA AT 00Z INDICATE A GOOD THERMAL PATTERN ASSOCIATED WITH THIS TROUGH... WHICH ONLY THE ECMWF AND CANADIAN HAVE PICKED UP ON. THE SHORTWAVE IS FORECAST TO DIG SOUTHEASTWARD DOWN THE EAST SIDE OF THE LONGWAVE RIDGE AND GRADUALLY WEAKEN/ERODE THE SUBTROPICAL RIDGE ACROSS FLORIDA... CUBA...AND THE EASTERN GULF OF MEXICO BY 48 HOURS. ALSO... THE DEEP-LAYER LOW OFF THE COAST OF BAJA CALIFORNIA IN COMBINATION WITH THE DEEP LOW OVER THE CANADIAN MARITIMES SHOULD HELP MAINTAIN A BLOCKING-TYPE PATTERN ACROSS THE U.S.... WHICH MEANS THE STEERING FLOW SHOULD CHANGE LITTLE FOR AT LEAST THE NEXT 2-3 DAYS
With the NHC's 11 AM update, Wilma became the 12th hurricane of the season. Looks like those Gulf coaster's and oil speculators can rest a little easier, but people in southern Florida will have to watch out. The current 5 day track has it curving around the western tip of Cuba and crossing the southern tip of Florida by the weekend.
From today's 11 AM discussion:
WILMA IS BEING UPGRADED TO A HURRICANE BASED ON SUBJECTIVE DVORAK CLASSIFICATIONS OF T4.0 FROM ALL AGENCIES...AND OBJECTIVE T NUMBERS FROM UW/CIMSS OF T4.5 SINCE 09Z. ANOTHER RECONNAISSANCE AIRCRAFT IS SCHEDULED TO BE IN THE SYSTEM THIS AFTERNOON. COLD CONVECTION IS BEING MAINTAINED OVER THE CENTER...AND STRONG UPPER-LEVEL OUTFLOW CHANNELS CONTINUE TO THE NORTHEAST AND SOUTHWEST OF THE CENTER. OCEANIC HEAT CONTENT AHEAD OF WILMA IS HIGH. THE ONLY INHIBITING FACTOR IS THE DRY AIR MASS IN THE GULF AND EXTREME NORTHWESTERN CARIBBEAN...BUT THE LARGE AND GROWING CIRCULATION OF WILMA SHOULD BE ABLE TO KEEP MUCH OF THIS AIR FROM REACHING THE CORE. A HIGH LIKELIHOOD OF RAPID STRENGTHENING IS INDICATED BY THE SHIPS RAPID INTENSIFICATION INDEX...AND IT IS LIKELY THAT WILMA WILL BE A MAJOR HURRICANE WHEN IT ENTERS THE SOUTHEASTERN GULF OF MEXICO. AS WILMA ACCELERATES NORTHEASTWARD LATE IN THE FORECAST PERIOD...WIND SHEAR IS FORECAST TO INCREASE...BUT THERE MAY NOT BE ENOUGH OF IT TO WEAKEN WILMA VERY QUICKLY. HOWEVER...IT IS WORTH REMEMBERING THAT THERE IS LITTLE SKILL IN LONG-RANGE INTENSITY FORECASTS.
Wow, I don't think anybody expected Wilma to become a Cat 5 hurricane overnight, but there it is. Quite possibly the strongest storm on record too. Probably won't stay that strong for very long, but long enough for the tips of the Yucutan penninsula and the western tip of Cuba to get whacked by the edges. Looks like western Cuba will probably take the brunt of Wilma as it makes the turn towards Florida
From today's 5AM discussion:
WILMA IS A CATASTROPHIC CATEGORY FIVE HURRICANE THAT IS MOVING OVER VERY WARM WATERS...TYPICAL OF THE NORTHWESTERN CARIBBEAN SEA...AND WITHIN AN ENVIRONMENT OF LIGHT SHEAR. HOWEVER...DESPITE THE FAVORABLE LARGE SCALE ENVIRONMENT...WILMA IS NEAR ITS MAXIMUM POTENTIAL INTENSITY AND FURTHER STRENGTHENING IS NOT ANTICIPATED. MOST LIKELY...THE SMALL EYE WILL COLLAPSE FOLLOWED BY SLIGHT WEAKENING OR SOME FLUCTUATIONS IN INTENSITY. EYEWALL REPLACEMENT CYCLES WILL LIKELY CONTROL THE INTENSITY FOR THE NEXT 2 TO 3 DAYS WHILE THE HURRICANE IS OVER THE NORTHWESTERN CARIBBEAN SEA. THEREAFTER...ONCE WILMA REACHES THE SOUTHEASTERN GULF OF MEXICO AND ENCOUNTERS THE WESTERLIES AND HIGH SHEAR...WEAKENING SHOULD BEGIN.
I have PGP 9.0.2 installed on my laptop. For some reason, PGPTray gets busy now and then and spikes the CPU load to 100%. No idea why, or what it's doing. Not a lot of disk activity, but it sure kicks the laptop's fan into high gear. Does this for 5-10 minutes or so, stops, then starts back up again maybe 15 minutes later.
After a little bit of digging, I found this thread in the PGP Forums that seemed to explain everything (something about PGPTray polling disks). But then toward the end of the thread it's mentioned that the problem was fixed with 9.0.2. So maybe I'm having another problem. I'll have to check and see if it's doing the same thing on the computer at home.
So apparently my undead friend Oreo has communicated with the land of the living through one of my friends to say that yes, he really is getting married this time. No idea when or where. Communicating with the dead is never very reliable after all. And then there's the matter of wallets.
Wilma is starting to finish it's pummeling of the Yucutan and heading off to Florida. Fortunately for those in Florida, NHC isn't forecasting Wilma to get much stronger and to pass through pretty rapidly.
From today's 5AM NHC discussion for Wilma:
AIR FORCE RECON OBSERVATIONS INDICATE THAT THE INNER CORE OF WILMA...WHICH WAS DISRUPTED DUE TO ITS INTERACTION WITH LAND...IS BECOMING SLIGHTLY BETTER DEFINED. HOWEVER THE EYE IS STILL QUITE LARGE...ABOUT 65 N MI ACROSS...AND RAGGED. THE CENTRAL PRESSURE HAS NOT CHANGED MUCH SINCE THE HURRICANE EMERGED FROM NORTHEAST YUCATAN...AND THE CURRENT INTENSITY OF 85 KT IS BASED ON PEAK FLIGHT-LEVEL WINDS OF 91 KT TO THE SOUTH OF THE CENTER...AND SOME RESPECT FOR A CENTRAL PRESSURE OF 961 MB. SATELLITE IMAGERY SHOWS THAT THE CLOUD PATTERN IS ELONGATED ALONG A NNE-SSW AXIS WITH MOST OF THE DEEP CONVECTION DISPLACED TO THE NORTH-NORTHEAST OF THE CENTER. THIS MAY BE A HARBINGER OF INCREASING SHEAR...BUT IT IS ASSUMED THAT WILMA'S INNER CORE WILL BE ABLE TO AT LEAST TEMPORARILY REDEVELOP...AND THAT SOME RESTRENGTHENING WILL OCCUR TODAY. HOWEVER...THE GLOBAL MODELS INDICATE A SUBSTANTIAL INCREASE IN VERTICAL SHEAR WILL OCCUR AS WILMA NEARS THE FLORIDA PENINSULA... WHICH...ALONG WITH POSSIBLE ENTRAINMENT OF DRIER LOWER-LEVEL AIR... WOULD LEAD TO WEAKENING. SINCE THE TROUGH INTERACTING WITH WILMA IS QUITE STRONG...THE CYCLONE IS FORECAST TO BECOME EXTRATROPICAL AT A RELATIVELY LOW LATITUDE BY ABOUT 48 HOURS.
Yesterday, TS Alpha (2005) blossomed in the middle of the Carribean and will be dumping a bunch of rain over the Dominican Republic and Haiti today. After that, it looks like it will be carried out into the Atlantic along with Wilma without much additional strengthening.
A long, long time ago during my undergrad days, one of the requirements for my 4th year physics lab course (way back in 1990 or so) was to do some kind of research project. The project my lab partner and I settled on was to investigate the use of copper filters in the x-ray beam to reduce skin entrance exposure to pediatric cardiac cath patients. For the past few years it's something that's been pretty standard in fluoroscopic equipment now (although not something I can claim any credit for, I don't think). I thought for posterity, I'd post our original write-up here.
Disclaimer: This work is from a project I did for one of my undergraduate labs a few years ago. The only review process this project has undergone was being scrutinized by my supervisor for this project and by the TA who marked it. Check my bibliography for other published papers on the subject.
If you'd like to comment on or criticize this, email me at eugenem@ix.netcom.com (or just leave a comment)
Pediatric patients undergoing cardiac catheterization procedures can be subjected to large skin entrance exposures from both fluoroscopy and cine modes. To reduce the radiation exposure to the patient while minimizing loss in image quality, a small amount of copper filtration is added. In conjunction with standard radiation protection procedures (shielding and minimizing procedure time) the reduction in patient exposure can be reduced quite significantly. Preliminary phantom investigations demonstrate a decrease in exposure of up to 70% with the addition of 0.2 cm of copper filtration and little image quality degradation.
Cardiac catheterization procedures involving pediatric patients can subject both the patient and operators to high radiation exposures. Because of the small size of the patients involved, children receive higher gonadal and thyroid exposures from scattered radiation. Children are also more sensitive to the effects of radiation than adults.
Several methods of reducing patient dose have been suggested such as minimizing procedure time, reducing the x-ray field size or placing lead shielding underneath the patient. Newer pulsed fluoroscopy systems where the x-ray beam is pulsed at the same rate as the video refresh rate of the monitor (30-60 pulses/second) has also shown to result in a significant saving in patient dose as well as improving image quality [7, 8, 13].
In keeping with the principle of ALARA, a method of reducing patient exposure by introducing additional beam filtration is proposed and investigated in this work. The additional filtration reduces radiation exposure by hardening the beam and removing the low energy x-rays which do not contribute to the formation of the x-ray image. Since the average kVp for pediatric patients is between 50-60 kVp, this should result in a large reduction in patient exposure without significant degradation in image quality. Aluminum filtration was also examined to compare the reduction in exposure between copper and aluminum. A similar method employed by den Boer et al [8] demonstrated a 55% reduction in patient exposure and 69% reduction in operator exposure with the combination of a high-output pulsed fluoroscopy and 0.4 mm of copper filtration.
Skin entrance exposures in typical cardiac catheterization procedures were examined for a Siemens cardiac catheterization laboratory equipped with a Siemens Polydoros 100 high frequency generator, Bicor biplane C-arms with variable FOV image intensifiers, Cinematic AEC 35 mm cine camera and Hicor digital imaging system.
 |
A simple phantom (Figure 1) consisting of a number of Lucite sheets was assembled to mimic a small patient approximately 6 cm thick. A small length of catheter was placed in the center of the phantom to serve as a reference marker and a rough indication of the image quality as the filters were added. |
| Figure 1: Phantom |
Skin entrance exposures for both fluoroscopy and cine were measured with a Keithly electrometer and a small ion chamber placed underneath the phantom. For fluoroscopy and cine, the skin entrance exposures for various amounts of aluminum and copper filtration were measured and graphed. Aluminum thicknesses ranging from 0-4.5 cm and copper thicknesses from 0-2.0 mm were used.
 |
Fluoroscopic and cine image quality was tested using a low contrast 2% phantom (Figure 2) and high contrast resolution fluoroscopy phantom (Figure 3). The low contrast phantom was made up of a 0.4 cm thick plate of aluminum with 8 holes of 4 different sizes, 1.6, 3.2, 4.8 and 6.4 mm in diameter. This plate was sandwiched between two 0.8 cm blocks of aluminum so that the holes in the aluminum sheet were 2% of the total thickness (2.0 cm). |
| Figure 2: Low contrast phantom | |
 |
The high contrast resolution phantom is a 0.5 cm thick block of plastic with 8 metal grids of varying line pair densities embedded in it. Line pair densities range from 20 lpi (lines/inch) to 60 lpi. |
| Figure 3: High contrast phantom |
Both phantoms were placed on the table top 30 cm away from the image intensifier and 40 cm above the x-ray tube and examined using fluoroscopy and cine. Image quality was evaluated using each phantom for a variety of filter thicknesses using the fluoroscopy display monitors and cine film.
For the low contrast phantom and up to 0.2 mm of copper filtration added, all 4 holes were still easily visible. With 0.4 mm of copper filtration, the smallest hole (1.6 mm) became barely visible and was no longer visible with 0.5 mm of copper filtration.
High contrast resolution (HCR) was measured at about 28 lpi (lines/inch) with up to 0.2 mm of copper filtration. At 0.4 mm and 0.5 mm of copper filtration, HCR dropped to 24 lpi.
With the phantom placed on the table and the ion chamber underneath the phantom, fluoroscopic skin entrance exposure rates in mR/min were measured first with no aluminum filtration, and then with increasing amounts of aluminum added to the x-ray tube. X-ray techniques (kVp and mAs) were also recorded. Table 1 shows the results with the results illustrated graphically in Figure 4.
|
||||||||||||||||||||||||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||||||||||||||||||||||
| Figure 4: Fluoro skin entrance w/ Al |
Figure 4 illustrates the dramatic decrease in skin entrance exposure with the addition of just 0.6 cm of additional aluminum filtration. The additional filtration results in a 60% reduction in patient exposure and only a slight increase in x-ray technique (from 46 kVp to 50 kVp and 1.6 mAs to 2.7 mAs).
The same measurements were performed using copper filtration, with the results tabulated in Table 2 and illustrated in Figure 5.
|
||||||||||||||||||||||||||||||||||||||||
 |
||||||||||||||||||||||||||||||||||||||||
| Figure 5: Fluoro skin entrance w/ Cu |
The reduction in patient exposure is nearly 50% with 0.1 mm of copper and 67% with 0.2 mm with very little change in x-ray technique (Figure 5). For larger filter thicknesses, the reduction in patient exposure is small relative to the increase in x-ray technique and the expected degradation in image quality resulting from the higher techniques.
Table 3 shows the cine skin entrance exposure with copper filtration, illustrated in Figure 6.
|
 |
||||||||||||||||
| Figure 6: Cine skin entrance w/ Cu |
For cine procedures where exposure rates can be in the R/min range, 0.2 mm of copper filtration resulted in an 80% decrease in patient exposure with little change in technique. Unfortunately, due to time limitations and the arrival of a patient, fluoroscopy exposure rates were not obtained for copper filter thicknesses between 0.5 mm and 1.5 mm and only 3 measurements could be made in cine mode.
Inserting a small amount of additional filtration is a simple and effective way of obtaining significant exposure savings for pediatric patients undergoing cardiac catheterization procedures where they may be subjected to high radiation doses. From a practical viewpoint, copper would appear to be the most ideal filter, since copper provides much greater reduction in patient exposure and is much thinner than the equivalent amount of aluminum. An additional 0.2 mm of copper filtration appears to provide an optimum amount of filtration which maximizes the radiation exposure reduction and minimizes the degradation in image quality.
This past weekend, I strapped on the running shoes again. It's been a long time since I stopped running. 9 years ago when I moved to Detroit was when I stopped. There simply weren't any safe runnable areas around me. Then I moved to Charleston SC, where again there weren't a lot of decent bikable or runnable areas that didn't have traffic speeding by at 40 or 50 mph. Sure, there are a lot of runners around. But by then, it had been a few years, and work was busy, so I never got started back up. Since then I've packed on about 30 extra pounds and have been missing my biking and running since then. There's also this thing about the weather too. I'm not sure how people do it around here, running around in 40°+ weather. I can hardly walk out the door to the car in the driveway without having all the life sucked out of me by the heat and humidity!
Now we have Nala, and I decided it was finally time to get off my lazy fat ass and start running again, both as a way to help burn off some of that excess lab puppy energy, and for me to finally get back into shape and drop some of this extra blubber.
Runners and coaches tell people that keeping a running log is a good way of keeping yourself motivated and tracking your progress. That's what this space is for, my running log.
Time: 0600
Temp: A cool and breezy 5°C.
Distance: maybe a few hundred meters
Just a quick one today. Nala didn't seem to interested in trotting along beside me. She kept stopping and looking at me, saying "What are we doing out here? Let's go eat!". It was her regular breakfast time after all. I think I'll try again later this afternoon.
I'm so out of shape it's pretty pathetic. The house is at the end of along straight cul-de-sac road and using the car odometer, it measured just about 0.7 miles out to the main road, which is just over 1 km. An out and back trip is about 2.2 km, which I've done several times walking with the dog. It's a nice walk. Eventually I'll be able to do the whole distance and longer without stopping, but for now, I take a walking pause every 300 meters or so. Don't want to push too hard this early after all. Good way to hurt yourself.
After being cooped up all day, Nala's pretty enthusiastic about getting out. She'll trot along pretty nicely on the way out at a relatively decent slow jogging speed, but then on the way back she either gets tired, or bored and slows down to a slow trot/fast walk. Then I end up almost pulling her along (which is almost the opposite of our trip out) and stopping more often to encourage her to keep going. Considering how much running and darting around she does at the dog park and how fast she goes, I'm inclined to think that maybe she's just getting bored with plain old trotting up the street. I might have to start bringing treats to make it interesting for her.
To help burn off some of Nala's excess puppy lab energy and get me trimmed down, I've decided it's time to start up running again. People say keeping a running log helps keep you motivated. It's something I've only done sporadically, usually as part of my journal writing years ago. I decided this time I would try it out, so I set up my RunningBlog as a place for me to log my runs, thoughts and observations during my running.
I think this is going to be fun!
Tom's Hardware has a good article today about decoding the apparent random numbers Intel now uses to label it's processors. Now that Intel and AMD appear to be leaving behind straight MHz/GHz classifications for their CPUs, they're resorting to model number designations, like Pentium 570, or some other seemingly random number. But apparently there's some method to the madness, although by the end of the article I was left with the impression that it won't be long before CPU designations start resembling car VINs. People are going to need databases to figure out just what kind of processor they're getting.
Buying the next computer is going to take a lot of research.
Scott Adams has a blog, and hosted on TypePad no less.
Should make for some entertaining reading.
My med student wife is trying to pimp me out to her fellow med student colleagues as a practice dummy so they can work on their exam techniques on Friday. She says it won't be anything invasive but I'm still not liking this. I think I will arrange to be very busy Friday.
Finally got around to upgrading to MT 3.2. Rather than upgrading the existing installation, I opted to make a copy of the database and a parallel installation of MT. That way, if something went wrong, reverting back to 3.17 would be simple. Fortunately nothing went wrong.
There are a number style sheet changes that will take me a while to integrate into this blog (if ever), but the RunningBlog is using the new templates. I gotta say, StyleCatcher is pretty sweet for grabbing new blog styles (themes in 3.2 now). I'm really liking some of the default styles available. The new interface is nice to work in too. Rebuilds seem to go faster in 3.2 also.
I think once I figure out how the styles are organized, changing the look of the blog is going to be easier to do.
Update: Rats...individual archives are broken. looks like a problem with SCode. Nope, turned out I needed to fix the mtview.php template and rebuild it. Duh.
Good article over at MobilityGuru about how to get the most out of your laptop battery. Part 1 is mostly about batteries technology and background. More tips to come in Part 2 according to the end of the article. Looking forward to the second part.
Update:Part 2 of the article is here
TS Beta (2005) sprouted up off the coast of Nicaragua and looks to be heading inland slowly. May even reach hurricane status before it reaches the coast.
5 weeks left in the season. The tally so far:
Tropical Depressions: 26
Named storms: 23
Tropical Storms: 11
Hurricanes: 12
Major hurricanes: 6 (Dennis, Emily, Katrina, Maria, Rita, Wilma)
Gamma? Delta? I wonder how many more greek letters this year's season will dig into. This year has already topped the revised predictionsfrom August for named storms and hurricanes. There are a couple of areas to watch still in the Atlantic and eastern Carribean. We may just see storms 24 and 25 by the time next week starts.
From this morning's Tropical Weather Outlook:
A TROPICAL WAVE IS SPREADING CLOUDINESS AND SHOWERS OVER THE LESSER ANTILLES... WITH THE MOST CONCENTRATED ACTIVITY NEAR THE WINDWARD ISLANDS. THERE ARE NO SIGNS OF TROPICAL CYCLONE FORMATION AT THIS TIME. HOWEVER... UPPER-LEVEL WINDS ARE GRADUALLY BECOMING A LITTLE MORE CONDUCIVE FOR GRADUAL DEVELOPMENT AS THE WAVE MOVES WESTWARD INTO THE EASTERN CARIBBEAN SEA.
A WEAK LOW PRESSURE AREA ASSOCIATED WITH A TROPICAL WAVE IS LOCATED ABOUT MIDWAY BETWEEN AFRICA AND THE LESSER ANTILLES. UPPER-LEVEL LEVEL WINDS ARE NOT FAVORABLE FOR SIGNIFICANT DEVELOPMENT.
Oreo arose from the dead to communicate with me last night and confirm that he did indeed get hitched on Tuesday. With nary a call, email or invite, he went and got married with no Hooligans in sight. Another opportunity for Hooligan celebration missed.
A hearty congratulations to the newlyweds! You owe us a big party though.
Don't forget your wallet when you move to Wisconsin.
Well, I'm certainly not going to get rich blogging. Good thing I never planned to.
My blog is worth $5,645.40.
How much is your blog worth?
Found at Walk This Way
Time: 1820
Temp: 16°C
Distance: ~2 km
Mornings are a little bit too cool to be working out lungs that haven't been worked hard in a long time, so I've shifted the running to when I get back from work. Still decently warm, and it should give me time to get acclimated. Cold air, warm lungs...recipe for getting sick.
A decent run up and back. Shin muscles (the wife could probably tell me the proper name for those muscles) on my left leg need some strengthening. They get all sore and weak halfway through my run, which makes the left foot very flappy. Doesn't make for very good running form.
Nala seemed to be enjoying today's outing, and kept pace with me for about 3/4 of the run.
Weight: a chunky 80 kg
I don't know if it's just me or other GoogleMail users, but spambots seem to be flooding GMail pretty hard the last couple of days. A few weeks ago, I might have seen 2 or 3 spam mails a week in the junk mailbox. Over the past two days I dumped 90 messages from the junk mailbox. At least GMail's spam filters seem to work fairly well. I don't think I've had to reclassify too many spams that got through into my inbox.
Had a fun little Howloween party for the dogs at the dog park today. There were a lot of dogs there today, and a few of them dressed up too! Nala was in her Superman costume for a few minutes, but it didn't stay on for very long once she started running around. So off it came except for the cape. There was Isabelle the pirate, Sam the pumpkin, Tide in Hawaiian shirt and lei, Bones in fairy wings, Sara all dressed up, and metal rocker Edgar. We even provided little treat bags with some biscuits, tennis balls and a rawhide chew for some of the bigger dogs. I think everybody had a pretty good time (people included).
Nala's definitely having more fun with the cooler weather. During the summer she'd be running around, and after 30-45 minutes she'd be done and pooped out. Today she was running around the whole two hours we were at the park, and pretty much non-stop at that.
Nala turned 10 months yesterday, and weighed in at 70 pounds today.
Time: 1030
Temp: 11°C
Distance: ~2.5 km
No running today. Just a brisk walk with the dog on a nice sunny morning. Might head out for a run later on today without the dog.
This year's pumpkins were on display today. Not as many as last year, but there were a few pretty good ones. This year's 1st place winner was the Blood Bank. Surgery's pumpkin was kinda cute.
