Antoine Schernberg1, Corinne Balleyguier2, Isabelle Dumas1, Sébastien Gouy3, Alexandre Escande1, Enrica Bentivegna3, Philippe Morice4, Eric Deutsch5, Christine Haie-Meder1, Cyrus Chargari6. 1. Radiation Oncology Department, Gustave Roussy Cancer Campus, Villejuif, France. 2. Radiology Department, Gustave Roussy Cancer Campus, Villejuif, France. 3. Surgery Department, Gustave Roussy Cancer Campus, Villejuif, France. 4. Surgery Department, Gustave Roussy Cancer Campus, Villejuif, France; INSERM U1030, Villejuif, France; Université Paris Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France. 5. Radiation Oncology Department, Gustave Roussy Cancer Campus, Villejuif, France; INSERM U1030, Villejuif, France; Université Paris Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France. 6. Radiation Oncology Department, Gustave Roussy Cancer Campus, Villejuif, France; INSERM U1030, Villejuif, France; Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France; French Military Health Academy, Ecole du Val-de-Grâce, Paris, France. Electronic address: cyrus.chargari@gustaveroussy.fr.
Abstract
PURPOSE: To examine the feasibility of using diffusion-weighted images (DWIs) coregistered with T2-weighted (T2w) sequence in treatment planning system to improve target delineation for image-guided adaptive brachytherapy (IGABT) in locally advanced cervical cancer patients. METHODS AND MATERIALS: We retrospectively examined the records of consecutive patients who were referred to our institution for pulse-dose-rate IGABT between May and December 2015 after concurrent chemoradiation. An MRI with T2w and DWI sequences with a maximum diffusion factor of 1000 s/mm2 on a 1.5 or 3.0-T MR scanner was performed after placement of the vaginal mold applicator. T2w defined gross tumor volume (GTVT2) and diffusion volume on DWI sequences (CTVDWI) were retrospectively delineated, if achievable, by radiologist and radiation oncologist. Concordances between CTVDWI and GTVT2, high-risk and intermediate-risk clinical target volumes (CTVHR and CTVIR) were evaluated. RESULTS: Forty-four patients were identified: 23 patients (52%) had a GTVT2 delineated, CTVDWI was delineated in 42 patients (95%). Intraobserver and interobserver conformity indexes were <0.75 in 11 patients (26%) and 23 patients (54%), respectively. There was a positive correlation between GTVT2 and CTVDWI volumes (p = 0.038, r = 0.58). Median CTVHR and CTVDWID90 were 37.3 Gy (17.1-48.9 Gy) and 33 Gy (22-97 Gy), respectively (p = 0.659). CTVDWI could have pointed CTVHR delineation modifications in a total of 32 of 44 (73%) patients with CTVDWI/CTVHR conformity < 1. CTVDWI volume was totally encompassed by CTVIR in all patients. CONCLUSIONS: These results suggest that DWI images as anatomical sequence without apparent diffusion coefficient mapping might have led to CTVHR modifications. Still, interobserver and intraobserver variations in delineation are substantial, and artifacts make it difficult to implement.
PURPOSE: To examine the feasibility of using diffusion-weighted images (DWIs) coregistered with T2-weighted (T2w) sequence in treatment planning system to improve target delineation for image-guided adaptive brachytherapy (IGABT) in locally advanced cervical cancerpatients. METHODS AND MATERIALS: We retrospectively examined the records of consecutive patients who were referred to our institution for pulse-dose-rate IGABT between May and December 2015 after concurrent chemoradiation. An MRI with T2w and DWI sequences with a maximum diffusion factor of 1000 s/mm2 on a 1.5 or 3.0-T MR scanner was performed after placement of the vaginal mold applicator. T2w defined gross tumor volume (GTVT2) and diffusion volume on DWI sequences (CTVDWI) were retrospectively delineated, if achievable, by radiologist and radiation oncologist. Concordances between CTVDWI and GTVT2, high-risk and intermediate-risk clinical target volumes (CTVHR and CTVIR) were evaluated. RESULTS: Forty-four patients were identified: 23 patients (52%) had a GTVT2 delineated, CTVDWI was delineated in 42 patients (95%). Intraobserver and interobserver conformity indexes were <0.75 in 11 patients (26%) and 23 patients (54%), respectively. There was a positive correlation between GTVT2 and CTVDWI volumes (p = 0.038, r = 0.58). Median CTVHR and CTVDWID90 were 37.3 Gy (17.1-48.9 Gy) and 33 Gy (22-97 Gy), respectively (p = 0.659). CTVDWI could have pointed CTVHR delineation modifications in a total of 32 of 44 (73%) patients with CTVDWI/CTVHR conformity < 1. CTVDWI volume was totally encompassed by CTVIR in all patients. CONCLUSIONS: These results suggest that DWI images as anatomical sequence without apparent diffusion coefficient mapping might have led to CTVHR modifications. Still, interobserver and intraobserver variations in delineation are substantial, and artifacts make it difficult to implement.