PowerPoint Presentation

Low-energy photons

- quality and “hardness” of radiation determined by filters (Al, Cu) - filters remove soft component of radiation - half value leyer HVL – reduce intensity by 50% - half value depth D½ - to achieve radiation with that corresponds to tumour depth - kV = superficial 50-150 kV (<5 mm depth) - orthovoltage 150-300 kV (5-10 mm)

- photoelectric effect - dosimetric profile