191 MRI in the treatment planning of radiation therapy in cervical carcinomas

Abstract

<h3>Purpose</h3> To evaluate MRI in the planning of radiation therapy in patients with cervical carcinoma especially in the design of lateral radiation treatment portals. <h3>Material and Methods First step</h3> 18 patients with cervical carcinoma (1 TIN-, 2 T2aN-, I T2bN0, 10 T2bN-, 2 T2bN+, 2 T3bN+) underwent simulation films with an isocentric four field technique based on palpatory findings (II patients: first group) and on diagnosis MRI and clinical findings (7 patients: second group). <h3>Second step</h3> MRI was then performed in treatment position with skin markings of the isocenter of the radiation fields. <h3>Third step</h3> for each patient the simulated lateral field was superim-posed on the midsagittal MRI Image and the simulated anterior radiation field on the midcoronal MRI Image. <h3>Fourth step</h3> the adequacy of the margins was evaluated by correlating the simulated treatment portals with MRI defined target volume. <h3>Results</h3> In the first group of patients (11 cases), MRI in treatment position has led to a change of the radiation fields in nine patients: six patients had a modification of the lateral fields (in one case we had to decrease the anterior and posterior border, in five cases we had to increase the posterior border). Three patients had a modification of the anterior portal (increase of the superior border) and of the lateral portal (increase of anterior and posterior border) these modifications ensured an adequate coverage of the posterior tumor border and of the uterine fundus with safety margins. In the second group of patients (7 cases) MRI in treatment position has led to a change in lateral portals in five patients (increase of the poSterior border) to ensure an adequate coverage of the posterior border of the cervix tumor. <h3>Conclusion</h3> Diagnosis MRI and MRI in treatment position are necessary to ensure an adequate coverage of the cervix tumor and of the uterine fundus especially in lateral fields when treating cervical carcinomas with a four field technique. Otherwise AP/PA pelvic radiotherapy is the safest technique.