Radiation refers to the phenomenon that part of the electromagnetic energy emitted by a field source travels away from the source and does not return to the source, causing significant harm to the human body. BOC Sciences has excellent radiation detection professionals and advanced detection equipment to accurately measure the intensity of radiation and analyze compliance with standards.
Radiopharmaceutical therapy (also known as molecular radiotherapy or targeted radionuclide therapy) involves treating patients with a radioactive substance (called a radiopharmaceutical) that targets cancer or other abnormal, diseased cells. This treatment is called targeted radionuclide therapy because the radiopharmaceutical selectively irradiates and destroys cancer cells while limiting radiation exposure to healthy tissue.
Dosimetry is the science of determining radiation dose by measurement, calculation or a combination of measurement and calculation. The technical name for radiation dose is absorbed dose; it is the amount of radiation energy deposited in the tissue divided by the mass of the tissue. Absorbed dose is the most important physical factor affecting the response of tumours and other parts of the body to radiation.
Absorbed dose determines how much tumor and normal tissue are affected by radiation. The higher the absorbed dose to the tumour, the more cells will be killed by the radiation and the greater the likelihood of cure. However, the higher the absorbed dose to normal tissue, the more likely and severe the adverse toxic effects of radiation. An important advantage of radiotherapy is its ability to irradiate and effectively treat tumours throughout the body. At the same time, irradiation of some normal organs is unavoidable. Therefore, the role of radiation dosimetry in targeted radionuclide therapy is to specifically determine, on a patient-by-patient basis, the amount of radiopharmaceutical to be administered that is most effective in treating the patient's disease while avoiding the absorbed dose of damage to normal tissues. Individualized radiation dosimetry is essential for planning the most effective and safest targeted radionuclide therapy for each patient.
Absorbed dose is the amount of radiation absorbed per unit mass. Absorbed dose is expressed in special units of the gigaret (Gy) and the milligray (mGy). Previously, the absorbed dose of radiation was expressed in rad. 1 mGy = 0.1 rad.
Equivalent dose is the product of the absorbed dose multiplied by the radiation weighting factor, which is the corrected value for the action of various sources of radiation (e.g. X-rays, gamma rays or electrons) on the body's tissues. Equivalent dose is expressed in sieverts (Sv) and milli-sieverts (mSv). Previously, it was expressed in units of Roentgen equivalent (rem). 1 mSv = 0.1 rem. For x-rays including CT, the weighting factor for radiation is 1.
Effective dose is used as a measure of cancer risk, adjusted based on exposure to radiation-sensitive tissues (e.g. gonads are the most sensitive). Effective dose is expressed in units of sieverts (Sv) and milli-sieverts (mSv). The effective dose is higher in younger people.
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