Three-dimensional spatial and dosimetric characterization of radiotherapy beams using laser read-out of TLDs

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6722290

Grupen-Shemansky, M E

A fully automated thermoluminescent detector (TLD) read-out apparatus has been designed and constructed for the express purpose of extracting spatially resolved dosimetric information using localized IR laser phosphor stimulation. A composite TLD plate has been designed that withstands the thermal stresses developed during laser heating. This detector and unique read-out scheme may be used to spatially and dosimetrically characterize ionizing radiation fields. The thermal response of TL materials cannot be fully characterized experimentally due to the inability of modern measuring techniques to accurately record the rapidly changing temperatures. Two-dimensional, time transient models have been derived to determine radial and axial temperature profiles in a TL layer when a 4 W CO{sub 2} focused or unfocused Gaussian laser beam is used to heat a single or multiple spots. Numerically derived temperature profiles were then used in a first-order kinetic model for the thermoluminescent emission. The experimental laser heated TLD read-out apparatus was used to image a {sup 60}Co radiotherapy beam. A 2.2 cm by 3.3 cm LiF detector was used to image the penumbra of a 5 cm by 5 cm collimated field of a Theratron-80. Qualitative and quantitative results agreed well with accepted beam depth dose profiles measured with ionization chambers in water bath phantoms.

• Research Organization: Arizona State Univ., Tempe, AZ (USA)
• OSTI ID: 6722290
• Country of Publication: United States
• Language: English

Related Subjects

440102* -- Radiation Instrumentation-- Radiation Dosemeters
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
61 RADIATION PROTECTION AND DOSIMETRY
655003 -- Medical Physics-- Dosimetry
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COBALT 60
COBALT ISOTOPES
DEPTH DOSE DISTRIBUTIONS
DESIGN
DOSEMETERS
DOSES
ELECTROMAGNETIC RADIATION
GAUSSIAN PROCESSES
HYDROGEN COMPOUNDS
INFRARED RADIATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZATION CHAMBERS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LASER RADIATION
LUMINESCENT DOSEMETERS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MEDICINE
MINUTES LIVING RADIOISOTOPES
MOCKUP
NUCLEAR MEDICINE
NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
PHANTOMS
RADIATION DETECTORS
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIATIONS
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
RESOLUTION
SPATIAL DOSE DISTRIBUTIONS
SPATIAL RESOLUTION
STRUCTURAL MODELS
THERAPY
THERMOLUMINESCENT DOSEMETERS
WATER
YEARS LIVING RADIOISOT