What is the ruling on working at an x-ray center that requires bringing in doctors to send cases to the center in exchange for a monthly commission, knowing that doctors force patients to go to the center and raise prices to cover their commission, and is it permissible to leave this job if the salary is tied to it?

You have done well to leave a job that involves bribery and injustice towards patients. Referring a patient unnecessarily to receive a forbidden commission and overcharging them is an act of injustice and deception. Seek a permissible job, for Allah facilitates matters for those who fear Him and provides for them from where they do not expect, as Allah Almighty says: "And whoever fears Allah - He will make for him a way out And will provide for him from where he does not expect" [Quran 65:2-3], and "And whoever fears Allah - He will make for him ease in his matter" [Quran 65:4]. If the new job stipulates the same forbidden conditions, it is not permissible for you to accept it. Be patient in your search for a job that is free of sin.