Biomaterial Database

The estimation of administered activity of krypton-81m for lung ventilation studies. 1995

N J Dudley, and K Griffith, and G P McGill, and A T Rogers

Medical Physics & IT Services, City Hospital, Nottingham, UK.

Measurement or estimation of the activity of krypton-81m administered to a patient during lung ventilation imaging is difficult, due to the short half-life and continuous delivery via pipework, and no satisfactory method exists. Calculations based on generator activity have the disadvantages that this activity may not be accurately known and that not all activity eluted is inhaled by the patient. The aim of this study was to develop a simple method for estimating the administered activity from the number of counts in each patient image. A formula based on the ratio of counts in 81mKr and technetium-99m lung ventilation and perfusion images was developed and reduced so that administered activity could be directly calculated from the total 81mKr counts, the 99mTc count rate, the administered activity of 99mTc and a constant representing the ratio of counts expected from equal activities of each radioisotope. The formula allows a direct calculation from the image acquisition data following an initial set of experimental work to establish the constant for a particular gamma camera and collimator system.

UI	MeSH Term	Description	Entries
D007727	Krypton Radioisotopes	Unstable isotopes of krypton that decay or disintegrate emitting radiation. Kr atoms with atomic weights 74-77, 79, 81, 85, and 87-94 are radioactive krypton isotopes.	Radioisotopes, Krypton
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D011829	Radiation Dosage	The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).	Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D011877	Radionuclide Imaging	The production of an image obtained by cameras that detect the radioactive emissions of an injected radionuclide as it has distributed differentially throughout tissues in the body. The image obtained from a moving detector is called a scan, while the image obtained from a stationary camera device is called a scintiphotograph.	Gamma Camera Imaging,Radioisotope Scanning,Scanning, Radioisotope,Scintigraphy,Scintiphotography,Imaging, Gamma Camera,Imaging, Radionuclide
D006207	Half-Life	The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.	Halflife,Half Life,Half-Lifes,Halflifes
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000280	Administration, Inhalation	The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.	Drug Administration, Inhalation,Drug Administration, Respiratory,Drug Aerosol Therapy,Inhalation Drug Administration,Inhalation of Drugs,Respiratory Drug Administration,Aerosol Drug Therapy,Aerosol Therapy, Drug,Drug Therapy, Aerosol,Inhalation Administration,Administration, Inhalation Drug,Administration, Respiratory Drug,Therapy, Aerosol Drug,Therapy, Drug Aerosol
D013668	Technetium Tc 99m Aggregated Albumin	A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in cardiovascular and cerebral circulation.	Tc 99m-Albumin,Tc 99m-Albumin Colloid,99m-Tc-HSA,99mTc-Albures,99mTc-HSA,99mTc-Human Serum Albumin,Tc-99m-HAM,Tc-99m-MAA,Tc-99m-Microalbumin,Tc-HAMM,Tc99m-Albumin,Technetium-99m Albumin Colloid,99mTc Albures,99mTc Human Serum Albumin,99mTcAlbures,Albumin Colloid, Technetium-99m,Albumin, 99mTc-Human Serum,Colloid, Tc 99m-Albumin,Colloid, Technetium-99m Albumin,Serum Albumin, 99mTc-Human,Tc 99m Albumin,Tc 99m Albumin Colloid,Tc 99m HAM,Tc 99m MAA,Tc 99m Microalbumin,Tc HAMM,Tc99m Albumin,Technetium 99m Albumin Colloid
D014692	Ventilation-Perfusion Ratio	The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung. (Stedman, 25th ed)	Ratio, Ventilation-Perfusion,Ratios, Ventilation-Perfusion,Ventilation Perfusion Ratio,Ventilation-Perfusion Ratios