Film dosimetry of megavoltage photon beams: a practical method of isodensity-to-isodose curve conversion
The central problems of photon beam film dosimetry are the dependence of film response upon photon energy, processing conditions, and film plane orientation. Researchers have overcome these problems by accurately fitting the depth-dependent sensitometric curve of Kodak XV-2 film to the equation OD(D,d) = OHs(1 - exp (- ..cap alpha.. 0(1 + ..beta..(d-dm))D)) where OD(D,d) is the optical density for dose D at depth d. ODs, ..cap alpha.. 0, and ..beta.. are constants characteristic of the film and beam energy but are independent of field size. Only central axis depth dose data for a single field are required to determine their values. A computer program based upon this equation has been written which successfully generates single field isodose curves from film data for a variety of field sizes with an accuracy of +/- 3%. Data are presented for 60Co, and 4 and 10 MV x rays.
- OSTI ID:
- 5630867
- Journal Information:
- Med. Phys.; (United States), Vol. 8:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
61 RADIATION PROTECTION AND DOSIMETRY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
GAMMA RADIATION
FILM DOSIMETRY
X RADIATION
ACCURACY
COBALT 60
DEPTH DOSE DISTRIBUTIONS
MATHEMATICAL MODELS
MEASURING METHODS
OPACITY
PHOTONS
RADIATION DOSES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COBALT ISOTOPES
DOSES
DOSIMETRY
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MASSLESS PARTICLES
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION DOSE DISTRIBUTIONS
RADIATIONS
RADIOISOTOPES
SPATIAL DOSE DISTRIBUTIONS
YEARS LIVING RADIOISOTOPES
550602* - Medicine- External Radiation in Diagnostics- (1980-)
550603 - Medicine- External Radiation in Therapy- (1980-)
655003 - Medical Physics- Dosimetry
990200 - Mathematics & Computers