DOSE DISTRIBUTION OF TELECOBALT ARC THERAPY

Journal Article · Sun Jan 01 04:00:00 EST 1961 · Proc. Japan Conf. Radioisotopes

OSTI ID:4683432

Onoyama, Y; Morikawa, S; Kawakatsu, N

Because of a skew dose distribution and maximum dose displacement in arc therapy, it is important to know a complete dose distribution. During arc therapy, both the source-skin distance and the field size on the skin vary continuously, so there is need of depth dose tables of numerous source skin distances and field sizes to calculate dose distributions. But it is practically impossible to use such a number of measured depth dose data. The difficulty is overcome by calculating these data from tumor air ratios at rotation center. The tumor air ratio in acrylite, used as a body phantom, is an exponential function of the tissue depths beyond 14 cm depth, and the effective absorption coefficient, mu , for that field size is obtained from the slant of this curve. The build up of the scatter accounted for the deviation from this relation in the region from 0 cm to 14 cm depth. Curves are obtained from which the tumor air ratio at any point along the central beam axis can be read. The calculated depth dose curves agree with measurements on the same source skin distance and field size. (T.F.H.)

• Research Organization: Kyoto Univ.
• NSA Number: NSA-17-030014
• OSTI ID: 4683432
• Journal Information: Proc. Japan Conf. Radioisotopes, Journal Name: Proc. Japan Conf. Radioisotopes Vol. Vol: 4th
• Country of Publication: Country unknown/Code not available
• Language: Japanese

Related Subjects

ABSORPTION
ACRYLIC ACID
AIR
BEAMS
BODY
COBALT
DISTANCE
DISTRIBUTION
GENERAL AND MISCELLANEOUS
MEASURED VALUES
MOCKUP
RADIATION DOSES
RADIATION SOURCES
RADIOTHERAPY
ROTATION
SCATTERING
SKIN
TISSUES
TUMORS