Abstract：
:Depth dose characteristics of 24-MV beams from a medical linear accelerator at various SSDs have been measured. The dose buildup, percent depth dose (PDD), and output were measured using ionization chambers and a diode detector under full scatter. Surface dose ranged from 8% to 51% depending upon the collimator setting at 100-cm SSD. It decreased by 10%-15% as distance was increased to 200 cm, but remained unchanged beyond this distance. The dmax migrated rapidly toward the surface with increasing field size at 100-cm SSD. At extended SSD, the dmax occurred at greater depths and shifted a little toward the shallow depths with increasing field size. Large field PDDs measured at extended SSD agreed well with those predicted from 100-cm data. The output followed the 1/(distance)2 relationship quite well. The extended SSD beam data are clinically useful when treating hemibody or performing total body irradiation (TBI) procedures.
journal_name
Med Physjournal_title
Medical physicsauthors
Jani SK,Pennington ECdoi
10.1118/1.596673subject
Has Abstractpub_date
1991-03-01 00:00:00pages
292-4issue
2eissn
0094-2405issn
2473-4209journal_volume
18pub_type
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