Search

This study includes four years of our clinical trials to improve implant quality in multicatheter accelerated partial breast irradiation (APBI). The progress in dosimetric and volumetric parameters of the treatment plans was evaluated. One hundred and ninety-one women, for whom treatment plans were made based on three dimensional imaging, were selected for the study. To evaluate progress made in our APBI procedure, following parameters and indices were taken into account: percentage of the target volume receiving the reference dose (PTVref), minimum dose in the target volume expressed as a percentage of reference dose (PTVmin), dose homogeneity index (DHI), and conformity index (COIN). Additionally, the plan quality index was calculated for every group as the sum of mean values of four evaluated parameters. PTVref have increased from the mean value of 83.4% at the beginning to recent 94.8%. The maximum value equals to 95.4%. The same trend can be observed with PTVmin value, which has been improved from 51.7% to 70.1%, maximally. DHI and COIN mean values present similar progress. DHI value increased from 0.53 level to 0.68, and COIN from 0.58 in 2009 to 0.74. Plan quality index has increased from 2.46 in 2009 to 3.06, recently. The implant quality is crucial for the accurate dose distribution. This paper shows the progress that was made in APBI procedure to improve implant quality. Nowadays, our implant technique is based on three-dimensional CT imaging results in acceptable dose distributions. [ABSTRACT FROM AUTHOR]

Purpose: In this study two different pre-planning methods (2D vs. 3D) were compared in respect to the implant quality as judged by volumetric and dose parameters of the treatment plans. The aim of this work was to evaluate the influence of the imaging modalities used for pre-planning purpose to the treatment plan quality., Material and Methods: Twenty-four patients treated with HDR multicatheter implants were randomly selected for experiment. All patients underwent breast conserving surgery. Flexible catheters were implanted into the breast through the template. Inter-catheter distance, number of planes and catheters were adjusted, in respect to the size and location of the target. Pre-planning was used to evaluate the implant geometry in respect to the target. Needles number and position were modified if necessary. There were two experimental subgroups consisted of 12 patients each. Different pre-planning procedure was employed in each group. In the first group 2D X-ray imaging system was used. In the second one the 3D pre-planning method based on CT was performed. Treatment plans were evaluated with parameters calculated based on dose-volume histograms (DVHs). Volumetric and dose parameters were used for comparison of the dose distribution between the two experimental subgroups., Results: The mean value of target coverage V PTV 100 is higher for 3D pre-planning than for 2D (91.7% vs. 86.1%). The dose that covers 90% of the PTV (D90) is also higher for 3D pre-planning than for 2D (4.2 Gy vs. 3.6 Gy). Similar relation can be observed for the values of dose homogeneity index where DHI obtained for 3D pre-planning is 0.60 and 0.53 for 2D. All differences were statistically significant with p < 0.05., Conclusions: Analysis presented in this paper showed that 3D pre-planning method improves the geometrical quality of the implant.