Although the medical community has become increasingly aware of risks associated with radiation exposure from medical imaging examinations and therapeutic radiopharmaceuticals, many of the risks can be easily avoided—particularly to women's reproductive organs.
The lack of effort to minimize radiation exposure to a woman's reproductive organs—specifically ovaries, endometrium and breasts—has been accredited to the recent explosion in the development of radiotracers for cancer diagnosis and targeted biomolecule therapy, wrote Anat Biegon, PhD, a professor of neurology at Stony Brook University School of Medicine in New York, and colleagues in an editorial published July 10 in Radiology.
Biegon and colleagues explained that there is a need for new guidelines regarding radiotracer development and use, as current guidelines for the performance of nuclear medicine dosimetry studies do not require the inclusion of "reproductively competent" women.
"The inclusion of women in defined hormonal states in dosimetry studies and recommending that both clinical and research nuclear medicine procedure on young women be performed in the least susceptible phase of the menstrual cycle could improve the safety and the diagnostic accuracy of nuclear medicine procedures in women," the authors wrote.
Biegon and colleagues performed a dosimetry study of the carbon 11-labeled radiopharmaceutical N-methyl- [11C] vorozole, an aromatase inhibitor. Men, postmenopausal women and premenopausal women who were imaged at two distinct point of their menstrual cycle were recruited for analysis.
Overall, the researchers found that the average standardized uptake values and radiation exposure at midcycle were three and 30 times higher relative to other phases of the cycle or postmenopausal women.
"Consequently, the calculated dosimetry for this tracer, based on studies using doses of four to eight mCi (148–296 MBq) per injection, predicts that a relatively conservative dose of 10 mCi (370 MBq) would have resulted in exposure above the Food and Drug Administration limit for ovaries (3000 mrem [30 mSV] for single injection) defined for research studies," the authors wrote.