Talk:Effective dose (radiation)

I36

What's these (I36), (I3) and (I6) in the table? I know a fair bit about this radiation protection stuff, have copies of key ICRP documents, and can't figure it out. Am I dense?--Yannick (talk) 02:40, 22 May 2012 (UTC)

Surely this is Incorrect ?

"A uniform field of penetrating radiation deposits the same amount of energy per unit mass in any organic material it hits."

From the earliest days of radiography it has been known that bones are more opaque to X-rays than soft tissues are. It therefore seems obvious that the same flux of X-rays passing into bones and soft tissues will deposit more energy in the bones. Granted bones are more dense than soft tissue, but an important effect governing X-ray absorption, and the X-ray contrast between bone & soft tissue, is the photoelectric effect in which the attenuation coefficient is proportional to the cube of the atomic number of the atoms which the radiation encounters. Absorption therefore depends on the chemical composition of the material being irradiated. AJS

It is incorrect, and I have changed it so that absorbed dose leads into biological effect logically. Dougsim (talk) 13:32, 23 February 2014 (UTC)

Organism

It is clear that although the concepts being discussed here could be applied to other organisms, the present context is clearly exclusively that of the human body; the various weighting factors would not apply to other organisms which, for example, lack bones. I have therefore replaced all instances of "organism" by "body". AJS

This article may be too technical for most readers to understand

I agree that the article seems technically daunting and so I re-ordered it into more sections and added more explanation around the word stochastic. I think it still needs more simplification, what do you think?

Effective dose really only addresses cancer and hereditary effects, can we emphasise that rather than stochastic? There is an increasing amount written about radiation induced heart disease and more and it is not obvious to me whether people regard those as stochastic effects or not.

If I don't get a reply I'll make some more edits Stephen David Williams (talk) 15:29, 26 August 2012 (UTC)

Cancer is the item of greatest concern, but there is a nearly infinite list of suspected or hypothetical effects. Teratogenesis, cognitive decline, heart disease, and I believe cataracts are all seen as stochastic effects. It's particularly odd that the "Uses" section now starts talking about skin and eye effects, where the big risk to the eyes is cataracts, not cancer. Another problem here is that there are some touchy word games to tiptoe around, because the ICRP and BEIR avoids defining effective dose as anything more than the result of an arbitrary equation, and warn against using effective dose to estimate cancer risk. In plainer language, it's just model, and they don't trust their own numbers. You can sense an arbitrariness in the tissue weighting factors, and we could argue all night about data quality.--Yannick (talk) 22:40, 8 November 2012 (UTC)

Also, what you've rewritten about committed dose is just wrong. It's possible, and even common, to calculate committed dose without going through effective dose. And committed dose is not just for background radiation. Every time a nuclear worker breathes in some plutonium or a doctor injects radiopharmaceuticals into you, there's a committed dose associated with that.--Yannick (talk) 22:50, 8 November 2012 (UTC)

Could I suggest to help with non-technical clarity, that the lead section is amended to read... "The effective dose in radiation protection and radiology is a measure of the cancer risk to a whole organism due to ionizing radiation delivered non-uniformly to part(s) of its body. It takes into account both the type of radiation, and the nature of each organ being irradiated."

The added last sentence serving to re-inforce the concept before launching into what it is not.Dougsim (talk) 12:51, 6 December 2012 (UTC)

Sounds good to me. Always better to define by positives than by negatives.--Yannick (talk) 14:54, 6 December 2012 (UTC)

It still seems a bit daunting, suggest further change to..."The effective dose in radiation protection and radiology is a measure of the cancer risk to the parts or the whole organism due to ionizing radiation. It takes into account both the type of radiation and the nature of each organ being irradiated. However, if an entire organism is radiated with uniformly penetrating external radiation, the total effective dose is equal to the equivalent dose." Dougsim (talk)

I've devised a graphic to help non-experts navigate the maze of does names and units and their relationships. I have also re-cast the article to make the flow logical, put text under the relevant headings, and make it more accessible to readers, whilst retaining that material which is good. Dougsim (talk)

I am a professional electrical engineer and consider myself to have a degree of mathematical competence. I therefore look to the mathematical definition of effective dose as the key to its meaning. However, I find the mathematical expression to be challenging (as they say), and would expect a lay person to find it impenetrable, so I think that a better explanation of it would be helpful for all. The difficulty I experience is that it seems to me that the mathematical expression is ambiguous in that the limits of the integrals are not stated. This is significant in the case of the integral in the denominator, since the resulting mass could be that of all tissues of type T, or that of the tissues of type T which are irradiated; other possibilities exist, all of which could give different numerical results. The expression simply does not convey a unique meaning.

A basic conceptual question for me is that I assume that fundamentally the health risk of radiation is proportional to the total radiation energy absorbed, not to energy/mass; if an obese person and a skinny one absorbed the same energy, would the skinny guy be at greater risk from stochastic effects ? So does the Sv have the right physical dimensions ? Or is there some fudge in the way it is calculated which corrects for this ? Or is my assumption wrong ? AJS — Preceding unsigned comment added by 77.96.59.93 (talk) 09:47, 1 February 2014 (UTC)

The calculated risk to fat and skinny would be the same if they received the same dose in sieverts. However in a uniform penetrating field they would in reality get different doses of irradiation and the dosimeter which measures this does not know the weight of the person.

Therefore the ICRP factors and coefficients used are averaged over the population, otherwise you would have to weigh and make a 3D model of every person to gain the most accurate assessment of stochastic risk. So these dose quantities are only approximations to guide and regulate practical radiation protection. The dose quantities are expressions of risk which are averaged and conservative. Dougsim (talk) 13:41, 23 February 2014 (UTC)

Photosynthesis looks like error

The 'Calculation of effective dose' section includes "The sum of effective doses divided by the quantity of photosynthesis to all organs and lungs and tissues of the body represents the effective dose for the whole body." - The word photosynthesis here seems nonsense - What should it be ? - Rod57 (talk) 17:37, 30 April 2016 (UTC)

... It was added 24 June 2015 in this edit with no explanation so I'm going to change it back. - Rod57 (talk) 17:52, 30 April 2016 (UTC)

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