Lymphomas is a proliferation of defensive cells of the immune system, initiating cancer in the lymphatic system.
The hematologist is the doctor who specializes in blood diseases.
The oncologist at a doctor specialized in diagnosing and treating cancer.
A radiotherapist is a specialist in performing radiation therapy that involves the use of X-rays with high doses of radiation to destroy cancer cells.
Remember that for the proper selection of health professional that treats lymphomas you must consider the nature, severity and symptoms you are presenting.