Why is gold 198 uses in medicine

The most common is technetiumm , which has its origins as uranium silicide sealed in an aluminium strip and placed in the OPAL reactor's neutron-rich reflector vessel surrounding the core. After processing, the resulting molybdenum precursor is removed and placed into devices called technetium generators, where the molybdenum decays to technetiumm. A short half-life of 6 hours, and the weak energy of the gamma ray it emits, makes technetiumm ideal for imaging organs of the body for disease detection without delivering a significant radiation dose to the patient.

The generator remains effective for several days of use and is then returned to ANSTO for replenishment. Another radiopharmaceutical produced in OPAL is iodine With a half-life of eight days, and a higher-energy beta particle decay, iodine is used to treat thyroid cancer.

Because the thyroid gland produces the body's supply of iodine, the gland naturally accumulates iodine injected into the patient. The radiation from iodine then attacks nearby cancer cells with minimal effect on healthy tissue. Nuclear imaging is a diagnostic technique that uses radioisotopes that emit gamma rays from within the body. The main difference between nuclear imaging and other imaging systems is that, in nuclear imaging, the source of the emitted radiation is within the body.

Nuclear imaging shows the position and concentration of the radioisotope. Both bone and soft tissue can be imaged successfully with this system. A radiopharmaceutical is given orally, injected or inhaled, and is detected by a gamma camera which is used to create a computer-enhanced image that can be viewed by the physician. Nuclear imaging measures the function of a part of the body by measuring blood flow, distribution or accumulation of the radioisotope , and does not provide highly-resolved anatomical images of body structures.

It highlights the almost microscopic remodelling attempts of the skeleton as it fights the invading cancer cells. A widely-used nuclear imaging technique for detecting cancers and examining metabolic activity in humans and animals.

A small amount of short-lived, positron-emitting radioactive isotope is injected into the body on a carrier molecule such as glucose. Glucose carries the positron emitter to areas of high metabolic activity, such as a growing cancer.

The positrons, which are emitted quickly, form positronium with an electron from the bio-molecules in the body and then annihilate, producing a pair of gamma rays. Special detectors can track this process, enabling the detection of cancers or abnormalities in brain function.

A CT scan, sometimes called CAT Computerised Axial Tomography scan, uses special X-ray equipment to obtain image data from hundreds of different angles around, and 'slices' through, the body. The information is then processed to show a 3-D cross-section of body tissues and organs.

Since they provide views of the body slice by slice, CT scans provide much more comprehensive information than conventional X-rays. CT imaging is particularly useful because it can show several types of tissue - lung, bone, soft tissue and blood vessels - with greater clarity than X-ray images.

Though a CT scan uses radiation, it is not a nuclear imaging technique, because the source of radiation - the X-rays - comes from equipment outside the body as opposed to a radiopharmaceutical inside the body. PET scans are frequently combined with CT scans, with the PET scan providing functional information where the radioisotope has accumulated and the CT scan refining the location. The primary advantage of PET imaging is that it can provide the examining physician with quantified data about the radiopharmaceutical distribution in the absorbing tissue or organ.

Radioisotopes Different isotopes of the same element have the same number of protons in their atomic nuclei but differing numbers of neutrons. How do radioisotopes occur? Radioactive decay Atoms with an unstable nucleus regain stability by shedding excess particles and energy in the form of radiation.

How are radioisotopes used? Radioisotope Half-life Use Hydrogen-3 tritium Carbon 5, years Used to measure the age of organic material up to 50, years old. Chlorine , years Used to measure sources of chloride and the age of water up to 2 million years old.

Lead Chromium Manganese Produced in reactors. Cobalt 5. Also used to irradiate fruit fly larvae in order to contain and eradicate outbreaks, as an alternative to the use of toxic pesticides. Zinc Produced in cyclotrons. Technetiumm 6. Produced in 'generators' from the decay of molybdenum, which is in turn produced in reactors. Caesium Ytterbium Iridium Also used to trace sand to study coastal erosion. Gold 2. Also used to trace factory waste causing ocean pollution, and to study sewage and liquid waste movements.

Americium Radioisotope Half-life Use Phosphorus Yttrium 64 hours Used for liver cancer therapy. Molybdenum Iodine 8. Samarium Lutetium 6. Used to treat a variety of cancers, including neuroendocrine tumours and prostate cancer.

Radioisotope Half-life Use Carbon They give off their radiation at a low dose rate over several weeks, and then the seeds can remain in the prostate gland permanently. Brachytherapy can be used for a wide range of prostate stages, PSA values, and tumor grades.

The components and dosages are modified for those with low, intermediate, or high risk prostate cancer. This treatment can also be used for many tumors which are considered too advanced for radical prostatectomy. As long as there is no obvious spread to distant areas of the body, like the bones, this treatment may be considered.