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NaISoil Radioactivity a b s t r a c t Humans are always exposed during their lives to ionizing radiation arising outside and within the earth. The exposure to these radiation occurs from natural sources such as radioactive elements in rocks and soil, internal exposure form radioactive elements through water, food and air and cosmic rays entering from outer space to earth's atmosphere. About 87% of the radiation dose received by human beings is due to natural radiation, it is essential to assess the radiation doses in order to control possible health effects from such natural sources. In this regard, a number of articles have been appeared for Malaysia in international research journals, which have been reviewed and complied in this article. Most of these articles are about the measurement of activity concentrations of primordial ( 238 U, 232 Th, 226 Ra and 40 K) and anthropogenic ( 137 Cs) radionuclide's and gamma dose rate in environmental samples using HPGe and NaI (Tl) survey meter.

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Intensity Modulated Radiotherapy (IMRT) is a modern type of external beam radiotherapy that conforms high radiation dose to the target with minimum dose to the organs at risk (OARs), making it an embellishment of every developed institution. The earlier publications didn't have much proofs of the clinical superiority of IMRT over other radiotherapy techniques. It was considered a complicated and expensive treatment technique but the advent of modern treatment and imaging modalities have made its rapid clinical implementation unquestionable. Now IMRT have grown up, it is not the technique in which non uniform beam intensities were generated just by metal compensators, now it has multileaf collimators (MLCs), rotational fan and cone beam delivery systems and robotic arm linear accelerators to cure the life threatening cancer diseases. IMRT with all its advances have some limitations including its high cost, increased staff work, increased time for its planning, and risks of marginal misses.