Some forms of elements are isotopic and can decay. we make use of these products protons radionuclides by using them in ways to image tissue or to treat it. we can couple a radioisotope to an element or compound to localize at certain tissues in question, to image it by detecting the molecule; this is known as a(n) tracer injection element when the same type of technique is applied but the purpose is to target something like a tumor and treat it with the radiation produced, we call this substance a placement tracer radiopharmaceutical nuclear medicine, whether used in diagnosis or to treat, involves the use of resonance ionizing radiation fluids so the amount of contact food dosage that is received by the patient should be considered.

The correct answers are as follows:
1. RADIONUCLIDES.
Radionuclides refers to an atom, which has excess energy that makes it to be unstable. The excess energy can be emitted inform of gamma rays, beta particles or alpha particles. These emissions are ionizing radiations which are used in various ways.

2. TRACER.
In nuclear medicine, a tracer refers to a chemical compound that can be used to explore the chemical reaction mechanisms by tracing the path of the chemical reaction. radioactive tracers are usually injected into the blood stream and use to monitor the biochemical reactions taking place in the body.

3. RADIOPHARMACEUTICALS.
Radiopharmaceuticals refers to a group of pharmaceutical drugs which are radioactive in nature. It is usually made up of a radioactive substance and an organic molecule. They are usually given to patients and monitored through imaging equipment for diagnosis or therapeutic purposes. 

4. IONIZING RADIATION.
Ionizing radiations refers to those radiations that have the sufficient energy capacity  to cause ionization in the medium they pass through. Ionization involves removing an electron from another atom. Ionizing radiations can cause damages to human tissues.

5. DOSAGE.
Ionizing radiation dosage refers to the amount of ionizing radiation that is applied to a particular part of the body. Radiation dose is measured in different ways, which include: absorbed dose, equivalent dose and effective dose. The amount of ionizing dosage given to human should always be considered in order to avoid damage to body tissues.