Sony Television. I have a sony (kd-28dx40u) that i've had for 5 years! I lent it to somebody and

Question

I have a sony (kd-28dx40u) that i've had for 5 years! I lent it to somebody and when they have given it back the picture has a strong green tint and i can only just make out the picture. The sound and everything else is ok.
Is it the tube that needs replacing? Please help!! Thanks. Kate