9 Reporting in Brachytherapy: Dose and Volume Specification

Reporting in Brachytherapy 159

Fig 6.1 : The figure illustrates the superiority of MRI compared with CT for discrimination between different types of tissues for a patient with cervix carcinoma III AB. A: Transversal CT showing a large soft tissue mass at the level of the uterine cervix, infiltrating into both parametria. No discrimination between GTV and uterine tissue is possible. B: Transversal MRI showing a high signal intensity mass indicating macroscopic tumour infiltrating into both parametria and into the left sacrouterine ligament. A clear distinction is possible from normal uterine tissue (arrows). C: Sagittal MRI showing a high signal intensity mass at the level of the cervix in the midsagittal plane extending mainly posteriorily with clear distinction from the uterine corpus (two contiguous sections are presented in Fig A,B and C). The GTV may appear to be different in size and shape, sometimes significantly so, depending on what examination technique is used for evaluation (e.g., palpation versus mammography for breast tumours, CT versus MRI for some brain tumours, CT versus MRI/ultrasound for prostate cancer). Therefore, the radiation oncologist should, in each case, indicate which method has been used for the evaluation and delineation of the GTV. Figure 6.1 illustrates the specific contribution of MRI for discrimination between different types of tissues.