The numbers on the study linked in the above post are a decade old and definitely have changed. Due to a continuous per year increase in imaging volume, the hours worked have increased, as have the incomes. By the way, there is nothing in the Radiology article that separates out interventional from non-interventional (interventional radiology is still considered part of diagnostic radiology).
Of note, this study includes a large number of academic rads, who work less clinical hours than private practice.
I think the main reason for the difference in female incomes is that many of the older, senior members of groups are more likely to be male and have a higher income. These partners are more likely to own part of the equipment and less likely to be employees.
Link to SDN post about more recent work hours survey:
http://forums.studentdoctor.net/showthread.php?t=101722
The actual source of this info is the AMA and is not available for free online.
All of that being said, I think there is definitely a decent number of opportunities to work part time in radiology. However, other specialties (primary care comes to mind) also have a decent number of these opportunities.