Portal de Periódicos da CAPES

244. Target volume definition with MRI and 68 Ga-DOTATOC-PET/CT for patients with meningiomas

2018; Elsevier BV; Volume: 56; Linguagem: Inglês

10.1016/j.ejmp.2018.04.255

1724-191X

Cristina Garibaldi, Mahila Ferrari, Marzia Colandrea, A. Cascio, M. Ciocca, Alberto Iannalfi, Emma D’Ippolito, S. Pesente, Chiara Maria Grana, Barbara Alicja Jereczek‐Fossa, Marta Cremonesi,

Glioma Diagnosis and Treatment

Abstract Purpose To investigate the impact of 68 Ga-DOTATOC PET/CT in addition to MRI and CT for retrospectively assessing the GTV delineation of meningiomas of the skull base in patients treated with particle therapy. Methods Sixteen patients underwent 68 Ga-DOTATOC PET/CT for diagnosis followed by constract-enhanced (CE) MRI and CT for treatment planning with particle therapy.GTV was defined on the CE-MRI fused to the simulation CT (CTsim) integrating information from the PET/CT. Three methods to delineate the PET volume were evaluated:manual ( PET man ), semiautomatic (42% threshold of SUV max , PET SUV 42 % ) and automatic adaptive thresholding method incorporating PET reconstruction parameters ( PET auto ) (iTA, TA). PET man volumes were delineated by the same nuclear medicine physician, while PET SUV 42 % and PET auto volumes were determined by medical physicists.The PET/CT, CE-RMI and CT sim were co-registered with a deformable image registration algorithm using the MIM Software.The overlapping region of MRI and PET man resulted in GTV common . Results The lesions had a median SUV max of 12.1 ± 6.8 (range:3.2–32.6).Overall, the GTV-MRI was larger than GTV-PET man in 7 patients (43.8%), smaller in 6 (37.5%) and almost the same in 3 (18.8%).The median value of the different volumes were:GTV-MRI = 14.3 ± 37.2 cc, GTV-PET man = 14.4 ± 47.0 cc , GTV common = 12.2 ± 33.6 cc , GTV-PET SUV 42 % = 8.3 ± 18.3 cc , GTV- PET auto = 11.3 ± 26.2 cc . GTV-PET SUV 42 % were always smaller than GTV-PET man ( Δ = - 51.0 ± 32.7 % ) and GTV-PET auto ( Δ = - 21.5 ± 12.7 % ) being variations in tumor heterogeneity not accounted for. Largest differences were observed for lesions showing high SD of SUV. The median difference between GTV-PET man and GTV-PET auto was 39.6 ± 29.5%. Conclusions 68 Ga-DOTATOC-PET/CT seems to improve the target volume delineation in skull base meningiomas, often leading to a reduction of GTV compared with MRI. The automatic adaptive thresholding delineation method may provide robust and reliable tool to help physician in segmenting PET images, reducing inter- and intra-observer variability.