Dosimetry characteristics of metallic cones for intraoperative radiotherapy

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · International Journal of Radiation Oncology, Biology and Physics; (United States)

DOI:https://doi.org/10.1016/0360-3016(91)90802-B· OSTI ID:5441456

Nyerick, C E; Ochran, T G; Boyer, A L; Hogstrom, K R ^[1]

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1. Department of Radiation Physics, University of Texas, M. D. Anderson Cancer Center, Houston (USA)

Dosimetry data were obtained on the first dedicated linear accelerator of its type designed for electron intraoperative radiotherapy (IORT) within an operating room. The linear accelerator uses a high dose rate, 9 Gy.min-1, to reduce the treatment time. Its chrome-plated brass treatment cones, designed with straight ends and 22.5 degrees beveled ends, are not mechanically attached to the collimator head, but are aligned using a laser projection system. Dosimetry measurements were made for each combination of energy (6, 9, 12, 15, and 16 MeV), cone size (diameters range from 5 to 12 cm), and cone type (22.5 degrees beveled or straight). From these data, depth-dose curves, cone output, and air-gap correction factors were generated that allow the calculation of the monitor setting for delivering a prescribed dose at any depth for any irradiation condition (energy, cone, air gap). Isodose data were measured for every cone using film in a solid water phantom. Scatter off the inside wall of the cone resulted in peripheral dose horns near the surface that were energy and cone dependent, being as large as 120%.

• OSTI ID: 5441456
• Journal Information: International Journal of Radiation Oncology, Biology and Physics; (United States), Journal Name: International Journal of Radiation Oncology, Biology and Physics; (United States) Vol. 21:2; ISSN IOBPD; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
655003* -- Medical Physics-- Dosimetry
ACCELERATORS
DEPTH DOSE DISTRIBUTIONS
DOSES
DOSIMETRY
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HYDROGEN COMPOUNDS
LEPTONS
LINEAR ACCELERATORS
MEDICINE
MOCKUP
NUCLEAR MEDICINE
OXYGEN COMPOUNDS
PHANTOMS
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
SCATTERING
SPATIAL DOSE DISTRIBUTIONS
STRUCTURAL MODELS
THERAPY
WATER