Room: Exhibit Hall | Forum 4
Purpose: To correlate V12 to the number of lesions and total tumor volume in single-fraction stereotactic radiosurgery (SRS) for patients with multiple brain metastases (BM) by using clinical treatment data of Leksell Gamma Knife ICON.
Methods: The skull dose volume histogram (DVH) of 13 patients in SRS single-fraction treatment with lesion number from 1 to 5, and total target volume from 0.018 cc to 12.747 cc were collected and analyzed. The relationship between dose and volume for those 13 patients followed the power-law relationship of V(n) = a(n, VT)*Dâ?»Ê³â?½â?¿â?¾, where V is the skull volume that received the dose D, and a(n, VT) and r(n) are the variables that determined the shape of the DVH curve. n is the number of targets and VT is the total target volume. Furthermore, in order to evaluate higher target number cases, five single fraction Gamma Knife treatment plans with lesion numbers of 3, 13, 8, 3+13=16 and 3+13+8=24 (3 consecutive courses treated for a patient) were analyzed and the DVH were power-law fitted and r(n) was determined.
Results: A weak positive correlation between r(n) and number of targets, total volume of target, and V12 were found (R2 = 0.1257, 0.1616, and 0.1459 respectively). However, a significant positive correlation between total target volume and a(n, VT), V12, and V12-VT were determined (R2 = 0.7354, 0.9541, and 0.7399 respectively). There was no correlation between a(n, VT) and total target number.
Conclusion: In this study, a model to correlate V12 in terms of a number of targets and total target volume were developed. The model was derived from clinical multiple BM cases treated with the Leksell Gamma Knife ICON in our institution. Our findings may be useful as additional clinical guidelines for treatment planning and plan evaluation.