CT Scans

beechescomposter

Barcode wrote: »

Thanks Beeches. In the booklet York hospital sent me, it says (to paraphrase) that the radiation exposure from a CT scan is about the same as that you would normally be exposed to in around three years by natural means.

I'm not sure if the MRI can do the same thing (?). This might be because some tumours tend to show up on certain scans and not others. My brother's pheo, for instance, was detected by a CT scan after he had some contrast dye. I don't know if it would have shown as clearly on an MRI.

I hadn't heard of words like pheochromocytoma and SDHB until last year. Now I'm a bit more informed. The only thing that surprises me is why more things DON'T go wrong in our bodies given the damage our DNA receives on a daily basis. As I understand it, having a mutation doesn't guarantee you will develop a tumour; but the soldier is not guarding the door, so to speak. And for that reason, it's sensible to have annual screening.

Yes the booklet is about right. College of Radiologists quote 4.5 years for abdomen and pelvis but this is on top of and not instead of natural radiation. For comparison the dose from a chest x ray is the equivalent of three days worth of radiation.

As the conclusion I pasted before hints, the problem with replacing CT with MR is the limited availability (a CT scan takes seconds while and MRI scan of the abdo might take 1/2 hour) and the lack of experience in reporting these scans compared to CT which is more straightforward and has been around longer. I would not like to look for a paraganglionoma on an MRI but if there is a previous one to compare it to its not so difficult.

If you are a youngish woman I think you should discuss the issue with your consultant. For most patients (elderly or already suffering from cancer) the risk of CT is probably overstated but this is not true for CT used for screening particularly in younger people.

Need_More_Money_2

beechescomposter wrote: »

If you are a youngish woman I think you should discuss the issue with your consultant. For most patients (elderly or already suffering from cancer) the risk of CT is probably overstated but this is not true for CT used for screening particularly in younger people.

Except that you will not find any evidence to support there being a risk at all.

The benefit of screening must depend on the liklehood that the patient might have the disease and the consequences of not detecting it

Barcode

I'm 26. Prior to this discovery, I had never had an MRI/CT scan or anything else. I have an appointment on the 12th of Oct to discuss my results (irrespective of what they are, annual follow-up needs to be planned), so I might mention it then. I'm more curious, rather than concerned about the risk to myself, which seems neglible compared to the benefits.

Are you a radiologist or somebody who works in this area?

I was actually joking with my partner that if I didn't have cancer before these tests, I will after from all the radiation (!?). Well, you have to try and see the humurous side, otherwise you would go quite insane.

beechescomposter

Need_More_Money wrote: »

Except that you will not find any evidence to support there being a risk at all.

The benefit of screening must depend on the liklehood that the patient might have the disease and the consequences of not detecting it

For immediate release

[SIZE=-1]For further information contact:
Arjun Makhijani or Lisa Ledwidge, IEER: 301-270-5500 [/SIZE]
[SIZE=+1]P R E S S R E L E A S E [/SIZE]Cancer Risks for Women and Children Due to Radiation Exposure Far Higher Than for Men

New National Academy of Sciences Report Raises Major Issues for Radiation Protection, Independent Institute Claims

Takoma Park, Maryland, July 7, 2005: The National Academy of Sciences (NAS) latest report on radiation risk, called the BEIR VII report, issued June 29, has major implications on how radiation protection regulations are made and enforced, according to the Institute for Energy and Environmental Research (IEER). "BEIR" stands for the Biological Effects of Ionizing Radiation. The NAS report issued this week updates the BEIR V report issued in 1990. The BEIR series of reports are the most authoritative basis for radiation risk estimation and radiation protection regulations in the United States.


But you, Need_More_Money, know better. The dangers of a little knowledge

Need_More_Money_2

beechescomposter wrote: »

For immediate release

[SIZE=-1]For further information contact: [/SIZE]
[SIZE=-1]Arjun Makhijani or Lisa Ledwidge, IEER: 301-270-5500 [/SIZE]
[SIZE=+1]P R E S S R E L E A S E [/SIZE]Cancer Risks for Women and Children Due to Radiation Exposure Far Higher Than for Men

New National Academy of Sciences Report Raises Major Issues for Radiation Protection, Independent Institute Claims

Takoma Park, Maryland, July 7, 2005: The National Academy of Sciences (NAS) latest report on radiation risk, called the BEIR VII report, issued June 29, has major implications on how radiation protection regulations are made and enforced, according to the Institute for Energy and Environmental Research (IEER). "BEIR" stands for the Biological Effects of Ionizing Radiation. The NAS report issued this week updates the BEIR V report issued in 1990. The BEIR series of reports are the most authoritative basis for radiation risk estimation and radiation protection regulations in the United States.


But you, Need_More_Money, know better. The dangers of a little knowledge

Actually I have quite a lot of knowledge in this field. :rolleyes: As I stated earlier the report you refer to is based on the linear no threshold hypothesis. This is bad science and has no data to show harm at low doses. Essentially they have said that because we know radiation is dangerous at very high doses (from atomic bomb survivors etc) then it must be dangerous at low levels too. This is like saying, we know vitamin C is dangerous at high levels so we'll assume all vitamin C is dangerous.
Your report does not provide evidence that there is any risk at all. It is a recomendation based on an unproven hypothesis. There is data to suggest the hypothesis is wrong and a great many radiation scientists do not believe in it.

You may this web page interesting. Whilst I'm generally critical of relying on the Internet for information, this page is written by the late Prof. John Cameron, a very well respected medical physicist working in the area of radiation protection.

Here is his reponse to an earlier BEIR report

"This study is probably the best scientific evidence, of many scientific data sources, to show that low levels of ionizing radiation exposure are without health hazard. The results clearly contradict the conclusions of BEIR that even small amounts of radiation have risk (in BEIR V and earlier reports), which have been largely based on the data from the Japanese atomic bomb survivors, who largely received their radiation exposures in very brief, high dose rate conditions and who are also now demonstrating that effective radiation health effects thresholds exist in the range of 20 to 200 rem."

beechescomposter

Need_More_Money, do you wear a lead apron or stand behind the screen when you x-ray patients? Why would you do this if you believe what you are writing. The dose to a patient from CT is many thousand or millions of times higher than the radiographer receives.
Barcode, I am sorry this is getting out of hand. The radiologists in York will have as much experience of CT and MRI as I have and will be able to advise your consultant as to the best way to screen you. I don't think anyone is disputing that you need screening and I don't want to put you off if they decide that CT is the only way they can do it.

Need_More_Money_2

beechescomposter wrote: »

Need_More_Money, do you wear a lead apron or stand behind the screen when you x-ray patients?

I never wear a lead apron and I don't xray patients. But I am exposed to ionising radiation.

beechescomposter wrote: »

Why would you do this if you believe what you are writing.

I do indeed believe what I am writing and I am qualified to understand the literature. Do you have any evidence that shows harm from low dose radiation? Are you aware that radiologists live longer than other Drs, even when they used to get significant radiation doses?

beechescomposter wrote: »

The dose to a patient from CT is many thousand or millions of times higher than the radiographer receives.

The radiographer would receive the dose all day every day without shielding. The patient is there for a very short time in comparison.

beechescomposter wrote: »

I don't think anyone is disputing that you need screening and I don't want to put you off if they decide that CT is the only way they can do it.

I didn't think she was worried. However many patients are less knowledgeable and can be put off by overzealous radiation protection techniques.
We already know of cases that suggest there is more harm done from fear of radiation than of harm from the radiation itself

beechescomposter

Need_More_Money wrote: »

I don't work in CT, but do work in a similar area. I only know a little about CT so I'm guessing here, but I suspect the 20mins per scan would include all the set up and positioning time. It might be that you just get set up once and then scanned from thorax right through to pelvis, in which case it wouldn't be anywhere near 3 x 20 mins. However, there might some contrast injection and/or to swallow which could lengthen the procedure.

I do work in CT and unlike yourself I do know what I am talking about.

Need_More_Money_2

beechescomposter wrote: »

I do work in CT and unlike yourself I do know what I am talking about.

Provide me with the evidence to show the harm then. And your evidence that I don't know what I'm talking about is.....?

I might not work in CT but we're talking about radiation with which I do work.

I don't doubt your knowledge of CT but what about the detail of radiation protection and radiobiology? Is that something you have experience of or is it based on guidance from experts in those areas?

My aim here is to ensure that people do not get put off having medical procedures performed due to worry about radiation. A sensible approach is required as there is no doubt that high doses are harmful. I have often had to deal with patients who do not want a scan done because they are concerened about radiation, despite the severe consequence of not detecting and treating the suspected condition.