You should consult a lawyer licensed in Pennsylvania who represents plaintiffs in medical malpractice cases, and do so right away. Obtain a copy of the CT scan on a CD, as well as any written report about the results of the CT scan, and bring it with you to the consultation with the lawyer.
Not legal advice as I don't practice law in Pennsylvania. It's just my two cents on the facts you describe. See a lawyer who brings medical malpractice cases right away, and consult your physician concerning the symptoms you are experiencing.
You should consult with and retain an attorney immediately for a number of reasons. The statute of limitations, or the time in which you must bring a suit, is two years from the date of injury or the date in which you first learn of the malpractice. Here there is an argument, albeit not that strong, that the statute is close to running out. In PA, in order to bring and perfect a medical malpractice law suit, you will need to obtain a Certificate of Merit from a like licensed surgeon. If you retain a lawyer now, you may be able to use your treating physician. You should also begin keeping a detailed daily journal of your treatment, limitations, pain levels, etc.