Analytic representation of electron central-axis depth dose data

Journal Article · Sun Nov 01 04:00:00 EST 1981 · Med. Phys.; (United States)

DOI:https://doi.org/10.1118/1.595038· OSTI ID:5939722

Jette, D; Lanzl, L H; Rozenfeld, M; Pagnamenta, A

We have examined a number of analytic representations of electron central-axis depth dose data current in the literature, testing them against sets of standard depth dose data. One of them, a two-parameter model of Shabason and Hendee, is recommended in situations in which good accuracy (approx.2%) is desired, with the values of the parameters determined by an approximation formula which we have developed elsewhere. For higher accuracy, we have developed a polynomial model which gives, typically, a standard deviation of the fitting polynomial from the data points of 1%, and a maximum deviation of 2%. Fitting polynomials obtained with this method possess the property of having zero slope at the position of actual maximum dose, and generally a fifth-order polynomial (requiring four nonzero coefficients) provided the most acceptable fit. The four parameters involved are determined through inversion of a 4 x 4 matrix, and we have tabulated these four coefficients for the standard data sets. The polynomial model is designed for interpolation in the range between the 100% dose depth and the 10% dose depth, and another fitting curve of the same type can be adjoined to cover depths less than the 100% dose depth. Key words: electron teletherapy, central-axis depth dose, polynomial model, interpolation

• Research Organization: Section of Medical Physics, Department of Therapeutic Radiology, Rush-Presbyterian-St. Luke's Medical Center, 1753 West Congress Parkway, Chicago, Illinois 60612
• OSTI ID: 5939722
• Journal Information: Med. Phys.; (United States), Journal Name: Med. Phys.; (United States) Vol. 8:6; ISSN MPHYA
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
655003* -- Medical Physics-- Dosimetry
BEAMS
BODY
DEPTH DOSE DISTRIBUTIONS
DOSIMETRY
ELECTRON BEAMS
ELECTRON DOSIMETRY
FUNCTIONS
LEPTON BEAMS
MEDICINE
NUCLEAR MEDICINE
PARTICLE BEAMS
POLYNOMIALS
RADIATION DOSE DISTRIBUTIONS
RADIOLOGY
RADIOTHERAPY
SPATIAL DOSE DISTRIBUTIONS
THERAPY
TISSUES