If you understood radiation safety better, FRiend,
you would understand that a technician running a CT
machine (what this thread is about) can control
the dose (a physical number), but cannot control
the exposure (a biological effect number dependent
upon what is irradiated).
And rad is the dose delivered (measured at a specific
point, like the midplane).
Rad (dose delivered) is the correct parameter.
ANd you should realize why there is a separate unit (Rem vs Rad) and what their relationship is(Rad x Qualtiy Factor=Rem)and that for gamma or xray radiation, the default QF = 1. So, for what we are talking about Rad=Rem.
In radiation safety, when speaking of exposure, ALL that matters is ‘what damage is done’. Biological damge. Why? Because different types of radiation do different amounts of damage per unit of dose. 1 Rad of gamma does not equate to the same damage as 1 Rad of alpha or neutron.
If I receive a dose of 20 Rad of neutron, my exposure, my ‘damage’ is 200-400 Rem (QF = 10-20 for neutron, depending on thermal vs fast).
If I receive a dose of 20 Rad of gamma, my exposure, my damage is 20 Rem. (QF = 1 for gamma)
400 Rem is a life threatening exposure. 20 Rem is not.
Hence, in radiation safety (Nuclear power oriented) Rem is VERY important and Rad is never used in relation to personnel dose.
And that is why in cases like this, where gamma or xray radiation is the issue, that Rad and Rem can be used interchangably, because the QF = 1.
In any case, it is biological damage that is the issue. And the unit that equates dose (Rad) to biological damge is the Rem.
So, still, while we quibble over Rad vs Rem, there was still no revelation as to the magnitude of the ‘over-exposure’ received by these patients. It is telling that the article does not give that and THAT was my point, just another fear-mongering article about the ‘dangers’ of radiation.