radiotherapy
The Spanish word 'radioterapia' translates to 'radiotherapy' in English. Radiotherapy is a type of treatment using radiation, often x-rays, to treat illnesses such as cancer by either destroying the cancer cells or stopping them from growing. It is a common and effective way to treat many types of cancer.
My uncle is receiving radiotherapy to treat his cancer.
This sentence is in the present tense and describes a current action that is taking place. The subject (Mi tío) is undergoing a process (is receiving radiotherapy) for a particular purpose (to treat his cancer).
Radiotherapy is an effective method to combat many types of cancer.
This sentence is making a general statement about radiotherapy. It is being described as an effective method against many types of cancer, telling us about its purpose and effectiveness.
Before starting radiotherapy, the doctor will discuss possible side effects.
This sentence is in the future tense and is describing an action that will happen before another (the discussion of side effects before the start of radiotherapy). It informs us about the usual practice or process that a doctor follows prior to starting a patient on radiotherapy.