Internal dosimetry provides methods for calculation of radiation dose and risks from radionuclides incorporated inside human body.[1] The Radionuclide deposited in human body will irradiate that person and will give dose to body until excreted or completely decayed from the body.
Routes of intake
There are four routes of intake (of radionuclide) namely,
Inhalation is the most prominent route of intake. In a radioactive area, radionuclide particulate may be suspended in the air and can enter the body by inhalation. These particulates may be deposited in different parts of the respiratory tract depending upon their aerodynamic diameter.[2] Monitoring techniques
In-vivo monitoring
Internal dose monitoring of the radionuclides which emit radiation which can penetrate out of the body.For example X-rays, gamma rays of sufficient energy.
Monitoring Systems
Whole Body Counter
A Whole Body Counter[3] has a low background arrangement with counting systems
HPGe detectors are replacing detectors for measuring the low energy and high energy photons with appropriate electronic systems.
Calibration of these systems is carried out with different type of physical and mathematical phantoms. Physical phantoms include BOMAB, LLNL, JAERI, thyroid and the knee phantoms. Some of the renowned mathematical phantoms are MIRD, CRISTY and nowadays voxel phantoms.
In-vitro monitoring
Monitoring of the radionuclides present in the body using the bio-assay sample taken out of the body.For example urine sample,sweat, fecal sample etc. Computer programs can be used for bioassay evaluations. [4]