title: Value of Magnetic Resonance Imaging Without or With Applicator in Place for Target Definition in Cervix Cancer Brachytherapy.
abstract: OBJECTIVE
  To define, in the setting of cervical cancer, to what extent information from additional pretreatment magnetic resonance imaging (MRI) without the brachytherapy applicator improves conformity of CT-based high-risk clinical target volume (CTVHR) contours, compared with the MRI for various tumor stages (International Federation of Gynecology and Obstetrics [FIGO] stages I-IVA).
  
  
  METHODS
  The CTVHR was contoured in 39 patients with cervical cancer (FIGO stages I-IVA) (1) on CT images based on clinical information (CTVHR-CTClinical) alone; and (2) using an additional MRI before brachytherapy, without the applicator (CTVHR-CTpre-BT MRI). The CT contours were compared with reference contours on MRI with the applicator in place (CTVHR-MRIref). Width, height, thickness, volumes, and topography were analyzed.
  
  
  RESULTS
  The CT-MRIref differences hardly varied in stage I tumors (n=8). In limited-volume stage IIB and IIIB tumors (n=19), CTVHR-CTpre-BT MRI-MRIref volume differences (2.6 cm(3) [IIB], 7.3 cm(3) [IIIB]) were superior to CTVHR-CTClinical-MRIref (11.8 cm(3) [IIB], 22.9 cm(3) [IIIB]), owing to significant improvement of height and width (P<.05). In advanced disease (n=12), improved agreement with MR volume, width, and height was achieved for CTVHR-CTpre-BT MRI. In 5 of 12 cases, MRIref contours were partly missed on CT.
  
  
  CONCLUSIONS
  Pre-BT MRI helps to define CTVHR before BT implantation appropriately, if only CT images with the applicator in place are available for BT planning. Significant improvement is achievable in limited-volume stage IIB and IIIB tumors. In more advanced disease (extensive IIB to IVA), improvement of conformity is possible but may be associated with geographic misses. Limited impact on precision of CTVHR-CT is expected in stage IB tumors.
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.
authors: Richard
authors: R
authors: Pötter
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Department of Radiation Oncology, Gran Canaria University Hospital, Las Palmas de Gran Canaria, Spain.
authors: Mario
authors: M
authors: Federico
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
authors: Alina
authors: A
authors: Sturdza
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Institute of Physics and Technology, Tomsk Polytechnic University, Tomsk Oblast, Russia.
authors: Irina
authors: I
authors: Fotina
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Department of Clinical Oncology, Medical University of Alexandria, Alexandria, Egypt.
authors: Neamat
authors: N
authors: Hegazy
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.
authors: Maximilian
authors: M
authors: Schmid
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria.
authors: Christian
authors: C
authors: Kirisits
authors: Department of Radiotherapy, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna, Austria. Electronic address: nicole.nesvacil@meduniwien.ac.at.
authors: Nicole
authors: N
authors: Nesvacil
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000532:radiotherapy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000532:radiotherapy