I like you #8 design, but i want to have a more fun, light feel. I looked at your designs, and I really like your design for Boom Skill, Ecofrag and The Mark Global . I like the the colors and feel of them. Maybe you can make it more of a logo that incorporates that it is medical and MRI. MRI is magnetic resonance Imaging.
also, can you maybe use different colors with number 8. maybe use red, black and grey. Also, i look forward to different designs like we talked about. Like the logos from boom skill, ecofrag and the mark global.