In nuclear medicine a hot spot describes a strong activity enrichment in one or more ranges of the organ or body part which is examined.
A pinhole collimator may be used if images of a hot spot and the surrounding with very high resolution are necessary. Zoom magnification or a converging collimator also may be used to improve resolution and assign the hot spot.

An intensifying screen is used to intensify the x-ray effect during radiation exposure of the x-ray film. Approximately 5% of the x-ray photons will be absorbed by the film only. Intensifying screens consist of a sheet of inorganic salts that emits fluorescent light when stroked by x-rays. The fluorescent input and output screens of the image intensifier are very similar to intensifying screens.
Calcium tungstate and rare earths are two common salts (also called phosphors) used for intensifying screens. For example, a calcium tungstate (CaWo4) screen can absorb around 40% of the x-ray photons and convert the radiation into light photons. A basic feature of this screen types is related to the position of the k-edge on the energy axis. Tungsten (W) is a heavy element has a k-edge at 69.5 keV, while that for rare earth elements is in around 50 keV.
The fraction of x-rays absorbed by a screen is depending on the speed. Factors affecting the speed of a screen: Mammography cassettes contain usually one intensifying screen, but most others use two screens per film cassette. The intensifying screen as part of a film screen system has been an important component in radiology to reduce the radiation dose of the patient. Today, the conventional film cassette is being replaced by an imaging plate used in digital systems.

See also Actinides, Cinefluorography and Added Filtration.

Iodinated contrast media contain small amounts of free iodide. Too much free iodide in the blood may cause hyperthyroidism in patients at risk, but contrast medium induced thyrotoxicosis is rare. The free iodide may also interfere with nuclear medicine diagnostic tests and treatment. However, iodinated contrast agents do not affect thyroid function tests (e.g., T3, T4, TSH) in patients with a normal thyroid.
Guidelines were prepared by the 'Contrast Media Safety Committee of the European Society of Urogenital Radiology' and discussed on the Tenth European Symposium on Urogenital Radiology in September 2003.
Tests of thyroid function before the injection of contrast agents may only be indicated in areas with dietary iodine deficiency. Patients with Graves' disease, multinodular goiter with thyroid autonomy, especially elderly and patients who lives in areas of iodine deficiency are at risk to develop thyrotoxicosis after IV contrast medium and should be monitored by endocrinologists after contrast enhanced CT exams. Prophylaxis may offer some protection in selected high-risk individuals but is not generally recommended.
The free iodide of iodinated contrast agents interferes with thyroidal iodide uptake and impedes diagnostic thyroid scintigraphy and radio-iodine treatment of thyroid malignancies for 2 months after administration.

Mallinckrodt, a Tyco Healthcare company makes and distributes products for respiratory care; bulk and dosage pharmaceuticals, primarily for pain relief and addiction therapy; and imaging agents for magnetic resonance, ultrasound, x-ray, and nuclear medicine applications. With worldwide manufacturing and distribution facilities, as well as worldwide sales offices, Mallinckrodt sells its products worldwide.

In June 2007 Tyco International Ltd. completed the separation of its healthcare business, which is named Covidien. Mallinckrodt, Inc. is now part of Covidien Ltd.

(MIP) CT Angiography images can be processed by maximum intensity projection to interactively viewing volumes of data, where the CT number of each pixel is given by the minimum CT number through the volume. The MIP connects the high intensity dots of the blood vessels in three dimensions, providing an angiogram that can be viewed from any projection. Each point in the MIP represents the highest intensity experienced in that location on any partition within the imaging volume. For complete interpretation the base slices should also be reviewed individually and with multiplanar reconstruction (MPR) software. The MIP can then be displayed in a Cine format or filmed as multiple images acquired from different projections.