Part-time job recs during summer/school year to boost resume?

Hi all! I am planning on entering my university's Radiation Therapy undergraduate program at the end of the summer once I get my GPA up and specific pre-reqs done. I still have 2 years of school left, next year will be additional pre-reqs and then all of the Radiation Therapy specific coursework + clinical is condensed in the last year of school. I switched my major from a very different (non-healthcare) field and currently have no healthcare experience on my resume. I am hoping to get some healthcare experience on my resume this summer and potentially extend it into working part-time through the school year. Does anyone have any advice for healthcare jobs that you would recommend for people in my situation? I have heard that Patient Transporter, CNA, MA, Radiation Aide/Assistant are good ones but am having trouble finding ones that don't require pre-training or prior experience. Any advice is greatly appreciated, thank you!!