cool paper on whiskers

I had a head CT scan a couple of months ago, followed by floroscopy (to not place a stent in my right carotid - CT scan lied). They won't try the left side for six months, though I'm going to try to get them to move it up. I know what my insurance is this year (already at maximum). I have no idea what it's going to be next year. Great way to make medical decisions.

I spent a few days wearing a dosimeter recently. Non-intuitive stuff.

You can cook an egg with nA..

--sp

When I was a kid I had a friend in Opelousas, La, and he had a geiger counter. We used to walk around measuring stuff. We found a red brick US Post Office that was super hot, probably uranium coloring in the bricks.

Radium clock dials were popular then, too. I did a science project based on scintillation of clock dial paint, detected by a 931A PMT, and won some award in the state science fair; first place maybe. There wasn't a lot of competition.

Those were the days, when there was lots of radioactive stuff for kids to play with.

Remember when shoe stores had those X-ray machines so you could see how your foot bones fit inside the shoe?

I have two "Boy Electrician" books, containing chapters on making your own X-ray machine (except for the tube), and fun things to do with it. It notes /in passing/ that if your skin reddens then you are probably using it too much.

I remember seeing these often on old gear especially those tuning caps - wow - I had no idea. I suppose I thought they just got some oil or something sticky in the chassis and that were just electronic dust bunnies. Learn something every day.

I found slightly different numbers, but still far lower than 4% of the LD50, by about an order of magnitude or 0.3%. Maybe there are different reported exposure values for the same procedure.

Whole Body CT scan = 1275 mrem

LD50/30 = 400 to 450 rem

While not an expert, ISTM that that is 'less bad' - whew! Hopefully the IGx treatment won't have too many side effects, you'll get your platelets back and get your meniscus tear repaired. {I had right meniscus repaired over 20 years ago - no problems with that knee since then - may you do as well}

Cheers indeed! -F

When they did my MRI, the tech said ther was a piece of metal in my leg. On the xray you can see what looks like wire, probably from one of thoes wire wheels. It's probably 30 years old or so.

Cheers

So, you've got your own personal metal whisker? ;)

It's kinda neat, it really distorts the Mag field. They can adjust the echo settings to get a better image, but it didnt interfere so no need.

Cheers

That's regular radiography. Computerised Axial Tomography uses a lot more X-ray photons, and the more it uses, the finer the details it can resolve.

I long ago sat through a lecture at medical conference that pointed out that 4% of the median lethal dose of radiation was what it took to get 1cm soft-tisue resolution.

I can't dig out that exact figure but

does point out that CAT scanning involves a much bigger radiation dose than regular two-dimensional radiography, and rather more than should be casually administered.

Head scans need less radiation - the head is smaller than the body. Body scans are nastier.

A body scan is closer to 10mSv. That's 2% of 5 Sv - not 4% - but I'm in the right ball-park.

And they are all doing their very best to give you cancer. It takes roughly six independent mutations to make all the changes to regular body cell required to make it cancerous, and radiation is rolling the dice all the time.

Order of magnitude off. Try 0.2%

I had no idea how large the dose from a CT scan is. I also found pages which seem to indicate they can use less radiation without significantly impacting the images.

I only found one source for dose data... I didn't make a project out of this. But I found a number of web sites which seem to be saying that the risk is much higher than you think and that we are exposed more than we need to be, not to mention the screw-ups that can happen.

If it is not ferrous it shouldn't distort the mag field. If it is ferrous I thought it would rip out of your skin from the mag field?

Titanium rods cause "shadows" and "reflections". Those are the words used by radiographers, so may be illustrative rather than the physical phenomena.

to

get 25

age

ill

y scans are nastier.

the right ball-park.

Ooops. My built-in error checker found it a couple of hours after I'd poste d the comment.

My guess is that my 1979 lecturer was talking about the first generation bo dy scanners, which were starting to get into hospitals at the time. Presuma bly the doctors using the machines were uhappy with the 4% of median lethal dose, and settled for lower resolution and a smaller radiation dose.

When I had my first MRI scan (in 1990, in the UK as a private patient - whe re it cost me 300 UK pounds) my consultant was delighted with the pictures which offered twice the resolution of the CAT scans he was used to (which c ost 150 UK pounds). He was looking at my intervertebral disks - which don't move around as much as other part of the thorax. Other areas probably move around enough with the heat-beat and intestinal peristalsis that the extra resolution wouldn't have been visible.

ghly six independent mutations to make all the changes to regular body cell required to make it cancerous, and radiation is rolling the dice all the t ime.

I've obviously been more nervous about CAT scans than I should have been, b ut even 0.2% of a lethal radiation dose isn't something to take lightly. Pa rt of the 1979 message was that body-scanners weren't all that useful - whi le the brain scanner was wonderful, and let clinicians see stuff that they couldn't otherwise see, the body scanner's main use was telling you that yo ur cancer had gotten too big, or too disseminated, to treat.

It was easy to make money out of body-scanners - the pictures made sense to everybody, even if they didn't tell the clinicians anything useful.

EMI was selling them to private practioners in the US, who shouldn't have b een able to find nearly enough legitimate patients to keep the machine busy .

Coleman lamp mantles used to be very hot, loaded with thorium.

John,

A mockery you said ? I love that word :-)

Indeed you're ABSOLUTELY right, where are brilliant physicists on that topic ?

Anyone could see in the ref you mention :

Continuous short if current Iwhisker < Imelt Intermittent short if Iwhisker > Imelt

So we know now from where comes the phantom hardware Heisenbug ... observing the phenomenon will increase the metallographic growth ... may be ?

Funny and strange that lead alloys are a mitigation of this natural process ! We all remember that lead is in the ultimate state of materials able to x-radiations.

I think the answer reside in the infernal oven of supernovaes in the universe.

Habib.