## Abstract

The concept of tissueÃ¢â‚¬Â�maximum ratios (TMR) as a basis of dose computations has posed problems when applied to the whole range of clinically used megavoltage beams. Another problem is the definition of scatterÃ¢â‚¬Â�maximum ratio (SMR) which assumes a value of zero at the depth of maximum dose. This paper describes new methods of measuring collimator and phantom scatter correction factors. The definitions of TMR and SMR are modified in order to compute phantom scatter at any depth, including depth of maximum dose. The revised concept is basic and general enough that it can be applied to xÃ¢â‚¬Â�ray beams of any energy, fields of any shape and isocentric as well as nonÃ¢â‚¬Â�isocentric modes of treatment.

Original language | English |
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Pages (from-to) | 230-237 |

Number of pages | 8 |

Journal | Medical physics |

Volume | 7 |

Issue number | 3 |

DOIs | |

State | Published - May 1980 |

## Keywords

- COBALT 60
- COLLIMATORS
- CORRECTIONS
- DEPTH DOSE DISTRIBUTIONS
- RADIOTHERAPY
- XÃ¢ËâRAY DOSIMETRY