Adverse reactions on contrast agents are rare, but like all other pharmaceuticals, contrast media are not completely without side effects.
Adverse effects to contrast media include allergic symptoms, anaphylactoid reactions, chemotoxic reactions, idiosyncratic reactions, contrast-induced nephropathy, iodide-induced hyperthyroidism and local tissue damage. An adverse reaction can be related to dose, the toxicity, and the physio-chemical properties of the contrast agent, for example osmolality, viscosity, and hydrophilicity.
Side effects such as a metallic taste in the mouth, generalized warmth or flushing, nausea and vomiting, increase with rapid flow and large volume of the injected agent. Although venous tolerance is usually good, there have been reports of sensation like burning, stinging or numbness and of venospasm.

Characterization of adverse reactions include:

An algorithm is a computer compatible equation. Computed tomographic algorithms reconstruct a function from its projections. A very large number of measurements are processed with complex mathematical operations to compute cross-sectional images.

The alpha decay is a corpuscular radiation. Two protons and two neutrons (a helium core) are emitted from the atomic nucleus. Because of the high biological effectiveness, the use of alpha particle radiation is not allowed in diagnostic nuclear medicine.

An anaphylactic reaction is a generalized allergic effect (also called anaphylactic shock). Allergic or anaphylactoid reactions range from sneezing, urticaria and itching, bronchospasm, facial and laryngeal edema to life-threatening symptoms including cardiovascular collapse, shock and respiratory distress.
Iodinated contrast materials are safe and widely used. However, anaphylactoid reactions occur rarely after administration of x-ray contrast agents. Most hypersensitivity symptoms appear short time after the intravenous, oral, rectal or other application (e.g., retrograde pyelography), only few are delayed by hours.
Patients with a history of allergic, asthmatic or reactions to contrast agents are at increased risk of anaphylaxis. Pre-treatment with corticosteroids and antihistamines decreases the incidence of an adverse reaction.

The angular response is the reaction of the detector to particles or photons which hit the detector at angles deviant from a normal to the facial plane of usual incidence.