MR imaging during intracavitary brachytherapy of vaginal and cervical cancer: preliminary results

Intracavitary brachytherapy is an effective treatment for gynecologic cancers. Twelve magnetic resonance (MR) imaging studies were performed during intracavitary brachytherapy (10 initial studies and two during repeat brachytherapy) in 10 patients with clear cell adenocarcinoma (n = 9) or epithelioma (n = 1). Fifty percent of the vaginal lesions did not demonstrate high signal intensity on T2-weighted images. Individually tailored molded applicators allowed easy detection of abnormal vaginal parietal thickening on T1-weighted images: Results in seven cases were concordant with results of clinical examination, and there were no false-negative results. MR imaging was useful in controlling the relationships between the tumor and the applicator and facilitated treatment planning, since the radiation dose to the tumor volume and adjacent critical organs could be calculated accurately. Limitations of MR imaging were underestimation of superficial vaginal tumors and the inability to differentiate between tumor and inflammation after recent surgery or repeat intracavitary brachytherapy. MR imaging during intracavitary brachytherapy appears to be a useful adjunct to clinical examination.