NUREG/CR-6204 "Questions and Answers Based on Revised 10 CFR Part 20"
may give some insight here.
Try Question 31 on page 15.
Q 31: Are students and volunteers subject to the occupational dose
limits? For example, nuclear medicine students, or "candy stripers"
that transport nuclear medicine patients or perform volunteer work in
a nuclear medicine department.
A 31: Occupational dose is defined in revised Part 20 as "the dose
recieved by an individual in a restricted area or in the course of
EMPLOYMENT in which the individual's assigned duties involve exposure
to radiation..." In the question above, the individual's assigned
duties do involve exposure to radiation as a necessary feature of
those duties; therefore, the students and volunteers are subject to
the occupational limits.
I hope this helps.