tl;dr - The UC system is useful as a lower-bound on radiology salaries since it's academic and in a highly-desirable location. Starting salaries are < $200,000, but increase to ~$390,000 while still an assistant professor.
Full post:
It's crazy that starting salaries are such a mystery. The only definitive source I've found is from the University of California system:
https://ucannualwage.ucop.edu/wage/
Pick a school, let's say UCLA:
http://radiology.ucla.edu/our-faculty
I went ahead and wrote a Python script to grab all of the faculty's salaries. Here they are:
Research scientists / Early assistant professors:
$41,580
$44,116
$63,960
$67,315
$101,713
$117,412
$118,963
$144,496
$154,903
$201,789
$229,771
$230,321
Associate professors:
$290,339
$342,093
$353,941
$357,934 [assistant professor]
$360,636
$361,708 [assistant professor]
$361,798 [assistant professor]
$372,237
$379,645 [assistant professor]
$382,737 [assistant professor]
$385,271 [assistant professor]
$390,793
$390,905 [assistant professor]
$391,268 [assistant professor]
$391,511 [assistant professor]
Professors:
$393,706
$393,755 [assistant professor]
$394,061
$400,899
$403,650 [assistant professor]
$403,684 [associate professor]
$407,222 [assistant professor]
$408,892
$409,850 [associate professor]
$414,429
$416,236 [assistant professor]
$418,433
$424,519
$425,012
$427,236
$431,867
$431,871
$434,691
$436,027
$436,350 [associate professor]
$444,604 [assistant professor]
$459,002 [department vice chair]
$465,543 [section chief]
$468,828 [department vice chair]
$469,826 [section chief]
$469,928 [vice chair]
$480,311 [assistant professor]
$487,228 [associate medical director]
$495,293
$502,091 [executive vice chair]
$508,807 [section chief]
$519,013 [vice chair]
$701,298 [chair]