121–130 of 167 posts
I liked the part about them causing "excess deaths." It's good to know your chance of dying is lower if you avoid CT scans...
Earlier quoted context omitted.
I don't know why this was down voted; while in an elevator one is not supposed to use a cell phone, because of this effect. At least in the elevator at work there is a sign that says so. http://microwavenews.com/news-center/using-cell-phone-elevat...
It was down-voted because it's nonsensical. Nobody is making cell-phone calls on an airplane.
[1] http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft#Statu...
Earlier quoted context omitted.
A lot of CT scans are well under 2 mSv. A lot more than you would expect from reading the worst-case estimates, as I mentioned above. The increase in cancer rates is interesting though, although if the main cause was radiation you wouldn't expect a few specific types to increase significantly and not others.
Common-sense statistical distinction: It's not even necessary to posit a 'radiation-associated cancer' category to account for differential cancer increases, as long as there are some cancers somewhere that pop up in response to things other than radiation. Existence proof: Cervical cancer, associated with a virus. We would not expect cervical cancer rates to jump to the same degree as $generic-cancer, because the ra…
To argue that cervical cancers should jump by a smaller amount than other cancers in response to radiation, showing that cervical cancers are largely caused by something other than radiation is useless -- you need to show that other cancers are largely caused by radiation.
Earlier quoted context omitted.
Some claim that wifi and cell phone emissions bouncing around in the cabin are also cause for concern. I've no idea if it's true, but I can imagine that inside an aluminum tube 150 wifi cards trying to connect might have some biological effect.
"Some claim" a lot of things. http://i.imgur.com/7LzpYl4.jpg
CT Scan doses vary wildly depending on the type of X-ray (chest, head, limb, etc.), the size of the person, and a lot of other things. The bigger the cross-section of the thing you put in a scanner, the greater the exposure. CT machines themselves also vary considerably. Newer machines are often more sensitive and employ better imaging software, so they can do their job while delivering a much smaller dose. Anyone wh…
As someone now in Hong Kong about to fly back home to SF, I have always tried to schedule my flights so that I minimize my exposure to day time radiation. I guess I'm in the minority, but it's something to consider when taking international flights.
>A single CT scan exposes a patient to the amount of radiation that epidemiologic evidence shows can be cancer-causing That does not look right to me. A single CT scan is 2-7 millisieverts, and exposures under 13 can not be linked to health effects - look for UNSCEAR in http://en.m.wikipedia.org/wiki/Sievert If you do the math by ICRP formulae, you end up with increase chance of cancer of 1 in 2600 over the next 20 y…
Epidemiological studies likely overstate the risk. If you read the Australian study for example, they certainly could not determine with certainty how many CT scans an individual had, because they did not include CT scans performed in hospitals. I would say that MOST CT scans performed in children would happen in hospitals. Therefore, a person having one CT may simply be a marker of them having many more CTs which ar…
FWIW I have had one CT scan in my life (in childhood I had a seizure which was probably caused by medicines I was taking) and they did one to rule out brain tumors. Probably a reasonable choice given that all the other tests for other stuff kept coming back negative. But I wouldn't suggest doing one without either a clear immediate need or else a significant concern and no materialized alternative causes for a symptom.
Any people here who go to the dentist? Specifically, the American Dental Association's guidelines for heathy persons suggest that * children receive 1 x-ray every 1-2 years, * teens every 1.5-3 years, * and adults every 2-3 years. ~ http://www.medicalnewstoday.com/releases/243952.php I was personally very surprised and alarmed by this.
Earlier quoted context omitted.
I'm not very good at math, but I'm reading that as a 0.7% increase in your chance of getting cancer. From 'Physics for Future Presidents', they say it is commonly accepted that we have a 20% chance of DYING from cancer before calculating for outside influences. http://books.google.com.au/books?id=6DBnS2g-KrQC&pg=PA98&lpg... Let's say the average person does not get a CT scan every year for 20 years, but rather gets 5…
that's an extra 0.7% for you. For a population of 300m (about the pop of the usa) that'd be an extra 2.1m people getting cancer.
CT Scan doses vary wildly depending on the type of X-ray (chest, head, limb, etc.), the size of the person, and a lot of other things. The bigger the cross-section of the thing you put in a scanner, the greater the exposure. CT machines themselves also vary considerably. Newer machines are often more sensitive and employ better imaging software, so they can do their job while delivering a much smaller dose. Anyone wh…
Earlier quoted context omitted.
Your body repairs tissue tears and damaged cells as well as fighting off infections and things but I don't believe it is well-equipped to deal with damaged genes. I could be totally wrong, though.
DNA repair is happening all the time -- this is a major benefit of having double-stranded DNA. Wikipedia offers DNA damage rates of 1e3 - 1e6 DNA damage events per cell, per day ( http://en.wikipedia.org/wiki/DNA_repair ). Almost all of these get repaired.