A NEW RECTAL DOSIMETRY CATHETER FOR USE IN RADIATION THERAPY OF CARCINOMA OF THE UTERINE CERVIX

¹ From the Department of Radiology, University of Miami School of Medicine, Miami, Florida

Irreversible radiation damage to the rectal mucosa is an avoidable complication of

[See figure in the pdf file]

intracavitary radium treatment of carcinoma of the cervix. In order to minimize this kind of complication, the exposure dose to the rectal mucosa should be measured as accurately as possible. With this in mind, a new dosimeter using lithium fluoride in small capsules which were inserted in a flexible catheter in tandem was developed. This "dosimetry catheter," inserted in the rectum for variable periods of time, gave measurements which were compared with those of a rigid scintillation probe that is in general clinical use. It has been demonstrated that the dose rates obtained with the scintillation probe and those obtained by the flexible dosimetry catheter are approximately the same to the level of the vaginal radium. At that point, the dosimetry catheter curves posteriorly following the normal anatomic contour of the rectosigmoid, and the exposure doses recorded are considerably less than the ones obtained by the rigid scintillation probe. Further careful studies of the actual dose range of tolerance to the rectal mucosa, as recorded by the rectal dosimetry catheter, may lead in the future to the better understanding of the dose range tolerance of the rectal mucosa to radium and radium-equivalent material.

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