What is your technique to calculate the vaginal surface dose in gyn intracavitary brachytherapy?

The limited published data on image based brachytherapy has not found any dosimetric correlate of upper vaginal morbidity. The traditional point dose tolerence has underassessed tolerence of the upper vagina

The recent multi-institutional EMBRACE study with different techniques and dose of cervical brachytherapy with more than 500 pts showed a 2 year actuarial probability of severe vaginal morbidity (grade ≥3) was 3.6% with most patients having grade 1 and 2 morbidities. That being said, when optimizing with IGBT, once should look at individual dwell weights to avoid hots sopts in the vaginal location and avoid using a graphical tool for optimization with intracavitary brachytherapy alone

Overall, I agree with the comments above. Vaginal surface dose was, historically, used in part as a surrogate for the dose to other surrounding structures. The maximum lateral surface dose allowed in treatment planning at MD Anderson varied depending on the type of applicator used and, in particular, the presence or absence of internal shields in the ovoids. Today, with LDR or PDR, we generally simply restrict the total activity in the ovoids to a level that we know will not exceed a total dose (including external) of about 120 Gy (with 2 cm shielded ovoids) or about 90-100 Gy with a cylinder or mini-ovoids. We rarely use a ring but the loadings would need to be somewhat more conservative than with mini-ovoids because the source is closer t...

I agree with @Dr. First Last but I have also heard that GEC ESTRO has found, using a rectal point, a good surrogate for vaginal toxicity. We await presentation/publication of this validated marker from their group.

I agree with @Dr. First Last and we await futher data.