RADIOBIOLOGY

• • ALARA - this approach results in the greatest benefit with the lowest risk to patients and radiation workers
• • Stochastic effect - if incidence of rad response increases with increasing rad dose, and is not observed for month or years.
• 1. Robert Hooke - first named the cell the biologic building block in 1665
• • Deterministic effect — if rad response increases in severity with increasing rad dose, and occurs within days after rad exposure.
• 1. Anton van Leeuwenhoek - in 1673, accurately described a living a cell on the basis of his microscopic observations
• 1. Schneider & Schwann - in 1838, showed that in all plants and animals, cells are the basic functional units. This is the cell theory
• 1. Watson & Crick - 1953, description of molecular structure of DNA
• • Macromolecules - very large molecules that sometimes consists of hundreds of thousands of atoms.
• • Organic molecule - life supporting and contains carbon
• • Water - most abundant molecule in the body and it is the simplest.
• • Catabolism - breaking down into smaller things of macromolecules.
• • Anabolism - production of large molecules from small molecules.
• • Protein - are long-chain macromolecules that consist of a linear sequence of amino acids connected by peptide bonds.
• • Protein synthesis- metabolic production of proteins, which it uses 22 amino acids.
• • Enzymes - molecules that allow a biochemical reaction to continue even tho they don’t directly enter into the reaction.
• • Hormones - exercise regulatory control over some body functions, such as growth and development
• Hormones - Secreted by endocrine glands
• • Antibodies - defense mechanism of human body against infection and disease.
• Lipids - Serves as fuel for body by providing energy stores.
• Carbohydrates - It provides fuel for cell metabolism
• • Glucose - the ultimate molecule that fuels human body.
• • Deoxyribonucleic acid (DNA) - serves as the command control molecule for cell function
• • Nucleotide- base sugar-phosphate combination, strung together in a one long chain macromolecule.
• • Cytoplasm - makes up the bulk of the cell and contains great quantities of all molecular components except DNA
• • Mitochondria - engine the cell
• • Genetic cells - include oogonium of female and spermatogonium of male
• Genetic cell - undergo meiosis
• • Somatic cells - all other cells of the body
• Somatic cells - undergo mitosis
• Interphase - period of growth of cell between divisions
• • G1 - pre-DNA synthesis phase
• • S - DNA synthesis phase, during this period, each DNA molecule is replicated into two identical daughter DNA molecules.
• • G2 phase - post-DNA synthesis gap of cell growth
• • Prophase - nucleus swells and DNA becomes more prominent and begins to take structural form.
• • Metaphase - chromosomes appear and are lined up along the equator of the nucleus. 
• • Anaphase - splitting of each chromosome at the centromere
• • Telophase - final segment of mitosis
• • Meiosis - process whereby genetic cells undergo reduction division.
• • Crossing over - results in changes in genetic constitution and changes in inheritable traits
• • Stem cells - immature cell and are more sensitive to radiation