Hey!

BSc in Radiology and Imaging Technology  (BRDIT) enables you to pursue a career as Radiologist and gain the skill of interpreting and diagnosing medical imaging. To identify illnesses and diseases, radiologists use mammography, x-ray, MRI, fluoroscopy, and CT scans. After this bachelor's, you will be able to diagnose patients like doctors do.

Diploma in Radiology Therapy is a 1 or 2-year postgraduate level program. In some colleges, the duration of this course is 1 year. You can make your career as a X-Ray Technician, Radiation Therapy Technologist, Radiation Protection Specialist, Diagnostic Radiographer, etc.
In pursuing jobs after both courses, your salary fully depends on your experience and knowledge.

I would suggest you to enrol for a proper bachelor's degree instead of a diploma. You can pursue diploma anytime later. You should pursue B.Sc. for better job opportunities.

Hope it helps!