It seems there might be a confusion in your question. DR4 and FR4 typically refer to different things, and they are not directly comparable.

1. DR4:

• Digital Radiography (DR): DR commonly stands for Digital Radiography in the medical field. It is an advanced form of X-ray imaging that uses digital sensors to capture and display X-ray images in real-time.

2. FR4:

• FR4 (Flame Retardant 4): FR4 is a grade designation for a type of flame-retardant material used in the manufacture of printed circuit boards (PCBs). It's a type of epoxy resin material reinforced with woven fiberglass cloth. FR4 is a common choice for PCBs due to its good electrical insulation properties and flame-retardant characteristics.

If you have a specific context or industry in mind, please provide more details so I can better understand and address your question.