Radiology, Vol 145, 479-483, Copyright © 1982 by Radiological Society of North America
The relationship between milligram-hours and dose to point A in carcinoma of the cervix
RA Potish, FC Deibel Jr and FM Khan
The relationships between the Fletcher and Manchester methods in dosimetry
of cancer of the uterine cervix were explored in order to compare dose
prescriptions between the systems, to optimize the best features of both
systems, and to establish the necessity for computerized dosimetry. A total
of 91 Fletcher-Suit radium applications was analyzed by a linear
least-square regression analysis to compare Point A and Point B doses of
the Manchester system will milligram-hours of the fletcher system. Although
moderately high correlations were found between milligram-hours of radium
and doses at Point A and Point B, it was concluded that direct comparisons,
particularly between individual patients, are fraught with dose
uncertainties of clinical significance. In addition, the correlation
between milligram-hours of radium and Point A dose was markedly affected by
the position of the colpostats and tandem, thus making it difficult to
formulate a simple conversion factor between the two systems.
