Thank you both for your responses. I agree with your assessment. I am just confused as to how the two companies I worked at in the past did not have to provide all of this proof for non-Class IIa detectors (when included in Class IIa devices). Further, I don't know why big detector companies are not getting Class IIa approval, and how they have sold product in EU without it, or the underlying proof. This is putting a monkey wrench in my present product introduction plans, and I want to be sure I really need this to be done before I put a lot of time into it. Thanks again.
Hello and welcome to the cove
It is very important not to confuse between medical devices and components thereof, wherever the latter are not medical devices in their own right.
I am no expert on DR, so I'm referring to the generic principles; you can then apply them to your field.
Speaking in general terms, there is no generic requirement for medical device components to qualify for CE-marking in order for a system (or device) containing them to qualify as well. As far as I know, this is true regardless of class and a given component criticality. There might be (easier) qualification routes that are based on such hierarchy, but typically there would be more than one path to CE-marking and it is up to you to consider and conclude which are accessible to your company / product, and which are preferred.
Of course, there could be specific requirements applicable to DR - as I stated above I'm no expert in this field. If this is actually the case, you can politely ask your NB to point the exact regulation section they refer to, and continue from there.
Having said all that, if the component (in this case, the detector) can be considered a medical device on its own, then yes, it would be required to comply with the MDD in order to be sold in the EC (even if the buyer esentially uses it as a component). The definition of a medical device can be found in the MDD and is quite clear in my opinion; you could try and read it on the detector as-received, and see if it holds. regardless of that, the detector manufacturers must comply with all (other) applicable EC directives before they sell these detectors in the EC, and if any of theses directives is one that leads to CE-marking then the detector should be marked accordingly (not necessarily as a medical device).
Cheers,
Ronen.