doiSerbia

Radiotherapy treatment planning: Benefits of CT-MR image registration and fusion in tumor volume delineation

Đan Igor (Department of Radiotherapy, Institute of Oncology of Vojvodina, Sremska Kamenica)
Petrović Borislava (Department of Radiotherapy, Institute of Oncology of Vojvodina, Sremska Kamenica)
Erak Marko (Department of Radiotherapy, Institute of Oncology of Vojvodina, Sremska Kamenica)
Nikolić Ivan (Clinic of Internal Oncology, Institute of Oncology of Vojvodina, Sremska Kamenica)
Lučić Silvija (Department of Nuclear Medicine, Institute of Oncology of Vojvodina, Sremska Kamenica)

Background/Aim. Development of imaging techniques, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), made great impact on radiotherapy treatment planning by improving the localization of target volumes. Improved localization allows better local control of tumor volumes, but also minimizes geographical misses. Mutual information is obtained by registration and fusion of images achieved manually or automatically. The aim of this study was to validate the CT-MRI image fusion method and compare delineation obtained by CT versus CT-MRI image fusion. Methods. The image fusion software (XIO CMS 4.50.0) was applied to delineate 16 patients. The patients were scanned on CT and MRI in the treatment position within an immobilization device before the initial treatment. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated on CT alone and on CT+MRI images consecutively and image fusion was obtained. Results. Image fusion showed that CTV delineated on a CT image study set is mainly inadequate for treatment planning, in comparison with CTV delineated on CT-MRI fused image study set. Fusion of different modalities enables the most accurate target volume delineation. Conclusion. This study shows that registration and image fusion allows precise target localization in terms of GTV and CTV and local disease control.

Keywords: radiotherapy, radiotherapy planning, computer assisted, tomography, x-ray computed, magnetic resonance imaging