screening/beir7Err uses an index to determine the associated Modality dose.
    with MRI: 0, with CT: 1, otherwise the Density birad index

    (biradIdx -> index)

beir7Err is called from screening/errrisk1405 and errrisk1404.
        At option -e errrisk1404 is used, which should not be used according
        to the man-page.

errRisk1405 is called from radiationRisk

radiationRisk receives a vector of indices specifying the bi-rad indices to
use for BC simulations. The vectors to use are produced by the various
Modalities. Modalities not specifying radiation doses (e.g., MRI) or
specifying constant doses (like CT) make zero-initialized vectors available,
other modalities produce vectors specifying bi-rad depending indices.

Values from these vectors are also used when computing sensitivity values (at
loop/maybedetect). They're ignored by Modalities not using bi-rad indices
(like CT or MRI), otherwise they determine which sensitivity (or m, or beta)
value to use)
