Below is a list of top radiology colleges in South India based on their reputation, infrastructure, faculty expertise, and academic excellence:

1. Christian Medical College (CMC), Vellore:
- Location: Vellore, Tamil Nadu
- About: CMC Vellore is one of the premier medical institutions in India, known for its excellent medical education and healthcare services.
- Courses: MD in Radio Diagnosis, DMRD (Diploma in Medical Radio Diagnosis)

2. St. John's Medical College and Hospital, Bangalore:
- Location: Bangalore, Karnataka
- About: As mentioned earlier, St. John's is one of the oldest and most prestigious medical colleges in Bangalore, offering a comprehensive radiology program.
- Courses: MD in Radio Diagnosis, DMRD (Diploma in Medical Radio Diagnosis)

3. Kasturba Medical College (KMC), Manipal:
- Location: Manipal, Karnataka
- About: KMC Manipal is a part of the Manipal Academy of Higher Education (MAHE) and is known for its world-class infrastructure and quality medical education.
- Courses: MD in Radio Diagnosis, DMRD (Diploma in Medical Radio Diagnosis)

4. Madras Medical College (MMC), Chennai:
- Location: Chennai, Tamil Nadu
- About: Madras Medical College is one of the oldest and most prestigious medical colleges in South India, offering a wide range of medical and paramedical courses.
- Courses: MD in Radio Diagnosis, DMRD (Diploma in Medical Radio Diagnosis)

5. Amrita Institute of Medical Sciences (AIMS), Kochi**:
- Location: Kochi, Kerala
- About: AIMS is a premier medical institution in Kerala, known for its state-of-the-art facilities and excellent medical education and research.
- Courses: MD in Radio Diagnosis, DMRD (Diploma in Medical Radio Diagnosis)

Please note that the rankings and reputations of these institutions may vary over time. It is always recommended to visit their official websites or contact them directly to get the most accurate and up-to-date information about their radiology programs, admission requirements, and facilities.

When choosing a radiology college, consider factors such as accreditation, faculty expertise, clinical exposure, research opportunities, and alumni network to make an informed decision.