PMC5711230_01
Diagnostic imaging: (a) axial CT image of the pelvis obtained at presentation shows a supravaginal  primary peritoneal clear cell carcinoma (PP-CCC) and an (b) axial and (c) sagittal T2-weighted MR image of the pelvis obtained one month following presentation which shows a supravaginal  primary peritoneal clear cell carcinoma. The lesion appears inseparable from the anterior wall of the proximal rectum.
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The patient then underwent completion staging workup, including CT scan of the abdomen and pelvis, which showed a  soft tissue mass in the deep pelvis (Fig. 1(a)). One month following initial presentation and CT, an MRI of the pelvis confirmed the presence of a  mass on the proximal vagina and vaginal cuff, which appeared to be inseparable from the anterior wall of the proximal rectum and rectosigmoid junction, likely representing local invasion (Figs. 1(b) and 1(c)).
Postchemotherapy (a) axial CT and (b) PET image of the pelvis shows a residual 3.3 cm prerectal/primary peritoneal clear cell carcinoma with FDG activity in the posterior vagina.
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Following chemotherapy, a 18F-FDG PET/CT scan revealed a 3.3 cm prerectal soft tissue mass with FDG activity in the posterior vagina consistent with active neoplasm (Fig. 2).
Isodose distributions on the (a) parasagittal and (b) paracoronal CT view for the approved external beam radiotherapy, and (c) parasagittal and (d) paracoronal T2-weighted MR view for the approved HDR brachytherapy treatment plan. The external beam  and  volumes are shown in the shadowed red and green contours, and the HDR PTV volume is shown in the shadowed red contour.
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The dose distribution for the approved plan is shown in parasagittal and paracoronal view in Figs. 3(a) and 3(b), respectively. The dose distribution for the approved plan is shown on parasagittal and paracoronal MR T2W images in Figs. 3(c) and 3(d), respectively.
Cumulative dose-volume histograms for (a) external beam and (b) high-dose-rate brachytherapy plans.
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The cumulative dose-volume histograms (DVHs) for , bladder, and rectum are presented in Fig. 4(a). Fig. 4(b). Following planning, Ir-192 HDR brachytherapy was used to deliver 15 Gy in 5 Gy fractions over two days.
A custom 30 millimeter diameter interstitial vaginal cylinder with perineal template.
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A custom 30 mm HDR interstitial cylindrical applicator was then placed into the vagina and a custom perineal template was sutured into place (Fig. 5).
Paracoronal ((a) and (c)) and parasagittal ((b) and (d)) T2-weighted MR and CT, respectively, through the custom interstitial applicator.
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Figure 7 illustrates the difference between soft tissue on the CT and MR scans, as well as the visualization of the applicator channels, in both paracoronal and parasagittal images.
Postradiotherapy CT (a) and PET image (b) of the pelvis obtained four months following radiotherapy shows near complete resolution of tumor.
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At four months follow-up, the patient underwent PET/CT imaging which revealed near complete resolution of tumor within the radiation fields (Fig. 8).