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BackgroundThe aim of the study was to examine on the CT basis the inter-application displacement of the positions D0.1cc, D1cc and D2cc of the brachytherapy dose applied to the bladder and rectum of the patients with inoperable cervical cancer.Patients and methodsThis prospective study included 30 patients with cervical cancer who were treated by concomitant chemo-radiotherapy. HDR intracavitary brachytherapy was made by the applicators type Fletcher tandem and ovoids. For each brachytherapy application the position D0.1cc was determined of the bladder and rectum that receive a brachytherapty dose. Then, based on the X, Y, and Z axis displacement, inter-application mean X, Y, and Z axis displacements were calculated as well as their displacement vectors (R). It has been analyzed whether there is statistically significant difference in inter-application displacement of the position of the brachytherapy dose D0.1cc, D1cc and D2cc of the bladder and rectum. The ANOVA test and post-hoc analysis by Tukey method were used for testing statistical importance of differences among the groups analyzed. The difference among the groups analyzed was considered significant if p < 0.05.ResultsThere are significant inter-application displacements of the position of the brachytherapy dose D0,1cc, D1cc and D2cc of the bladder and rectum.ConclusionsWhen we calculate the cumulative brachytherapy dose by summing up D0,1cc, D1cc and D2cc of the organs at risk for all the applications, we must bear in mind their inter-application displacement, and the fact that it is less likely that the worst scenario would indeed happen.

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Introduction: The aim of this paper is to study the distribution of the therapy dosage applied by a modified conventional “field in field” technique and compare it to the distribution of the dosage applied by the standard conventional technique.Methods: The study included ten patients with right side breast cancer, after they were exposed to radical mastectomy and chemotherapy. Radiotherapy dosage of TD 50 Gy in 25 fractions was applied to the anterolateral side of the right thoracic wall, with two opposite conventional tangential fields by the linear accelerator Elekta Synergy and the energy of 6 megavolts (MV). A delineation of the target volume (CTV – Clinical Target Volume) was done within conventional fields. At the XiO system for planning we included additional fields within the existing conventional fields, which was the so called “field in field” technique. On the basis of CTV the Dose Volume  Histogram (DVH) was calculated for conventional and “field in field” plans. VD90%, VD95%, VD107%, VD115%, CI and HI were calculated for both techniques. Means were pared with the paired Student's t-test. The results were considered significantly different if p<0.05.Results: VD90% and VD 95% were significantly higher for the “field in field” technique. Therefore, CI also favored the “field in field” technique (p=0.02). There was no difference in VD107% and VD115% between the compared groups. Consequently, there was no statistically significant difference in HI (1.13±0.03 vs.1.13±0.03, p=0.06).Conclusion: Conventional postoperative radiotherapy of localized right side breast cancer by “field in field” technique provides excellent coverage of the target volume by radiotherapy isodose.

As recommended by the GEC-ESTRO work group, it is important for the 3D image guided CT, or MRI based brachytherapy of cer-A B C Dvical cancer to verify what dose is received by 0.1 cm 3 , 1 cm 3 and 2 cm 3 (D 0,1cc , D 1cc and D 2cc , respectively) of the bladder and rectum volume (1). Intracavitary brachytherapy was applied with applicators type Fletcher tandem and ovoids, once a week on a HDR regime (high dose rate). Delineation of organs at risk (bladder and rectum) was made after each computer tomography (Panel A). The bladder and rectum were delineated on each