Program Information
Alarming Range of Seed Activities Ordered for I-125 Plaque Brachytherapy
B Merz1*, (1) Oregon Health & Science Univ, Portland, OR
Presentations
SU-E-P-8 Sunday 3:00PM - 6:00PM Room: Exhibit HallPurpose:
To investigate the variation in I-125 seed activities ordered by various clinics for their plaque brachytherapy cases under a standardized set of assumptions.
Methods:
A majority of the plaque programs in North America were contacted and a survey was designed to give a few standardized cases to allow inter-comparison of seed activities ordered. Tumor dose, treatment duration, number of seeds, plaque, and tumor apex were held constant in order to reveal differences in prescription point, seed type, and seed activity.
Results:
While the survey is presently underway, preliminary results show alarmingly wide variations between centers. Differences up to 45% have been found with 15% differences being common.
Conclusion:
Though knowledge of the TG-43 dose calculation formalism is common, a number of factors in the field of plaque brachytherapy lead to alarming differences in activity of I-125 seeds being ordered for a given tumor. Knowledge of the present reality of widely varying treatment activities, and thus doses to tumor and normal structures, should serve as motivation for centers involved in this modality to review their programs with others in the community and share their experiences.
Contact Email: