PURPOSE: Computer tomography-based (CT-based) tumor-volume definition is time consuming and is subject to clinical interpretation. CT is not accessible for standardized algorithms for the purpose of treatment-volume planning. We have evaluated the accuracy of target-volume definition based on the positron emission tomography (PET) data from an integrated PET/CT system with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) for standardized target-volume delineation. MATERIALS AND METHODS: Eleven patients with rectal cancer who were undergoing preoperative radiation therapy (RT) were studied. A standardized region-growing algorithm was tested to replace the CT-derived gross tumor volume by the PET-derived gross tumor volume (PET-GTV) or the biologic target volume (BTV). A software tool was developed to automatically delineate the appropriate tumor volume as defined by the FDG signal, the PET-GTV, and the planning target volume (PTV). The PET-derived volumes were compared with the target volumes from CT. RESULTS: The BTV defined for appropriate GTV assessment was set at a single peak threshold of 40% of the signal of interest. Immediate treatment volume definition based on the choice of a single-tumor volume-derived PET-voxel resulted in a tumor volume that strongly correlated with the CT-derived GTV (r(2) = 0.84; p < 0.01) and the volume as assessed on subsequent anatomic-pathologic analysis (r(2) = 0.77; p < 0.01). In providing sufficient extension margins from the CT-derived GTV and the PET-derived GTV, to PTV, respectively, the correlation of the CT-derived and PET-derived PTV was sufficiently accurate for PTV definition for external-beam therapy (r(2) = 0.96; p < 0.01). CONCLUSION: Automated segmentation of the PET signal from rectal cancer may allow immediate and sufficiently accurate definition of a preliminary working PTV for preoperative RT. If required, correction for anatomic precision and geometric resolution may be applied in a second step. Computed PET-based target-volume definition could be useful for the definition of standardized simultaneous internal-boost volumes for intensity-modulated radiation therapy (IMRT) based on biologic target volumes.
PURPOSE: Computer tomography-based (CT-based) tumor-volume definition is time consuming and is subject to clinical interpretation. CT is not accessible for standardized algorithms for the purpose of treatment-volume planning. We have evaluated the accuracy of target-volume definition based on the positron emission tomography (PET) data from an integrated PET/CT system with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) for standardized target-volume delineation. MATERIALS AND METHODS: Eleven patients with rectal cancer who were undergoing preoperative radiation therapy (RT) were studied. A standardized region-growing algorithm was tested to replace the CT-derived gross tumor volume by the PET-derived gross tumor volume (PET-GTV) or the biologic target volume (BTV). A software tool was developed to automatically delineate the appropriate tumor volume as defined by the FDG signal, the PET-GTV, and the planning target volume (PTV). The PET-derived volumes were compared with the target volumes from CT. RESULTS: The BTV defined for appropriate GTV assessment was set at a single peak threshold of 40% of the signal of interest. Immediate treatment volume definition based on the choice of a single-tumor volume-derived PET-voxel resulted in a tumor volume that strongly correlated with the CT-derived GTV (r(2) = 0.84; p < 0.01) and the volume as assessed on subsequent anatomic-pathologic analysis (r(2) = 0.77; p < 0.01). In providing sufficient extension margins from the CT-derived GTV and the PET-derived GTV, to PTV, respectively, the correlation of the CT-derived and PET-derived PTV was sufficiently accurate for PTV definition for external-beam therapy (r(2) = 0.96; p < 0.01). CONCLUSION: Automated segmentation of the PET signal from rectal cancer may allow immediate and sufficiently accurate definition of a preliminary working PTV for preoperative RT. If required, correction for anatomic precision and geometric resolution may be applied in a second step. Computed PET-based target-volume definition could be useful for the definition of standardized simultaneous internal-boost volumes for intensity-modulated radiation therapy (IMRT) based on biologic target volumes.
Authors: Clifton D Fuller; Jasper Nijkamp; Joop C Duppen; Coen R N Rasch; Charles R Thomas; Samuel J Wang; Paul Okunieff; William E Jones; Daniel Baseman; Shilpen Patel; Carlo G N Demandante; Anna M Harris; Benjamin D Smith; Alan W Katz; Camille McGann; Jennifer L Harper; Daniel T Chang; Stephen Smalley; David T Marshall; Karyn A Goodman; Niko Papanikolaou; Lisa A Kachnic Journal: Int J Radiat Oncol Biol Phys Date: 2010-04-18 Impact factor: 7.038
Authors: Marco Krengli; Maria E Milia; Lucia Turri; Eleonora Mones; Maria C Bassi; Barbara Cannillo; Letizia Deantonio; Gianmauro Sacchetti; Marco Brambilla; Eugenio Inglese Journal: Radiat Oncol Date: 2010-02-06 Impact factor: 3.481
Authors: Ralph A Bundschuh; Christina M Wendl; Gregor Weirich; Mathias Eiber; Michael Souvatzoglou; Uwe Treiber; Hubert Kübler; Tobias Maurer; Jürgen E Gschwend; Hans Geinitz; Anca L Grosu; Sibylle I Ziegler; Bernd Joachim Krause Journal: Eur J Nucl Med Mol Imaging Date: 2013-02-07 Impact factor: 9.236