[Chronologic dynamics of the "triple ring," caused by interstitial Iodine-125 brachytherapy with a novel method of image fusion].
OBJECTIVE
The aim of this study is to reveal the volumetric changes in tumor necrosis, reactive zone and edema following low-dose rate 1-125 interstitial irradiation of 20 inoperable (partially non-resectable, partially inoperable) low-grade gliomas.


METHODS
The volumes of the three regions on image-fused control CT/MRI images were measured for a 24-month period with 36 occasions. The delivered dose on the tumor surface (GTV) was 50-60 Gy. Dose planning and image fusion were performed with the BrainLab Target 1.19 software, mathematical and statistical computations were carried out with the Matlab Numeric Computation and Visualization software. The control images with the "triple ring" were fused with the planning images, and the isodose curves were adjusted to them.


RESULTS
Relative volumes normalized to volume of the reference dose were calculated and plotted in the time domain. The mean values of volumes were determined from the patients' measured data then a polynom was fitted to the mean values using the polynomial curve fitting method. The accuracy of our results were verified by statistical tools.


CONCLUSIONS
The new polynomial prediction approach using image fusion analysis of the volume of tumor necrosis, reactive ring and edema caused by interstitial irradiation as a function of time provides valuable information for 1. selecting the best patient's treatment option, 2. following up patient's condition and 3. planning reirradiation or reoperation if necessary.
Kolumbán
Zsuzsa
Z
Fôvárosi Onkormányzat, Szent János Kórház és Rendelôintézet, Idegsebészeti Osztály, Budapest.
Viola
Arpád
A
Major
Tibor
T
Bajzik
Gábor
G
Julow
Jeno
J
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D001932:Brain Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005910:Glioma / Q000473:pathology* / Q000532:radiotherapy*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011379:Prognosis; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012086:Reoperation; D019233:Retreatment; D013238:Stereotaxic Techniques; D013997:Time Factors; D014057:Tomography, X-Ray Computed
D007457:Iodine Radioisotopes