Visual outcome after phacoemulsification and IOL implantation in diabetic patients

Abstract

<b>1337</b> <h3><b>Objectives:</b></h3> To explore the value of hybrid 18F-FDG PET / MR in radiotherapy target delineation of lung cancer and compare with PET/CT. <h3><b>Methods:</b></h3> 30 lung cancer patients planning to undergo radiotherapy, with an average age of 55.45 ± 20.28 years, underwent whole body PET/CT scan and chest PET/MR scan on the same day. CT and PET images were acquired in free breathing mode, and then a breath-hold CT was performed. PET/MR gated acquisition under free breathing, MR and PET images acquired at the end of expiratory period. MR sequences include axial T1WI, fs T2WI, DWI, sagittal and Coronal fs T2WI. The 30 cases of lung cancer included 20 cases of central type and 10 cases of peripheral type. In PET/MR imaging, 8 cases of MR image artifacts were heavier, and the images met the standard after repeated scanning; The other 3 cases still had poor image quality after repeated scanning. The remaining 27 cases were analyzed by an experienced nuclear medicine physician and a radiotherapy physician. Compare the matching of PET and MR/CT between the two devices. The SUVmax and SUVmaen of the lesion were measured. MTV(metabolic tumor volume)and TLG(total lesion glycolysis) were obtained with 30% of SUVmax as the threshold, GTV(gross tumor volume) was delineated on CT and MR images, and the PTV(Planning Target Volume) was obtained from the fusion image. Non-parametric test is used to compare the differences between the two devices9 data. <h3><b>Results:</b></h3> Among the 27 cases, 18 cases had inaccurate matching between PET_CT and CT, with an average displacement of 1.3 (0.2, 1.5) cm and a maximum displacement of 2.5 cm, while PET_MR and MR were accurately matched. The radiation concentration of the lesions were more obvious in the PET/MR imges. SUV_max-PET/MR[26.43(23.42,33.38)] and SUV_mean-PET/MR[14.11(11.71,19.21)] were higher than SUV_max-PET/CT[19.16(12.22,20.87)] and SUV_mean-PET/CT[9.72(6.27,11.27)],(Z=-2.934,-2.837, P&lt;0.05); MTV_PET/MR[52.30(31.11,109.00)] was lower than MTV_PET/CT[58.16(33.51,124.00)], (Z=-2.845,P&lt;0.05); TLG_PET/MR[751.08(307.38,1835.29)] were higher than TLG_PET/CT[684.78(250.06,1503.14)],(Z=-2.936,P&lt;0.05). There were 18 cases of obstructive pulmonary atelectasis or obstructive pneumonia, in which PET_MR and MR could clearly distinguish the tumor from them in 16 and 15 cases, respectively;while PET _CT and CT could distinguish 10 and 8 cases, respectively(χ²=4.98,5.90,P&lt;0.05).GTV_MR[60.55(29.25,108.00)] was lower than GTV_CT[68.58(30.08,122.00)],(Z=-2.490,P&lt;0.05). There was no statistical difference between GTV_MRandMTV_PET/MR (Z=-1.956,P&gt;0.05), while GTV_CT was lower than MTV_PET/CT (Z=-2.401,P&lt;0.05). PTV_PET/MR[55.65(29.52,107.00)] was lower than PTV_PET/CT[62.23(30.08,122.00)], (Z=-2.936,P&lt;0.05). <h3><b>Conclusions:</b></h3> Compared with PET/CT, PET/MR has more accurate image matching in lung tumor imaging, it can more accurately locate the tumor body, and may become a more accurate imaging method for delineating target areas of radiotherapy. However, MR lung scanning technology is more demanding, the image is prone to artifacts, and often needs repeated scanning. Fig.1 Male, 70 years old, with central lung cancer. PET/CT: CT image (a) and PET/CT fusion image (b) cannot completely distinguish tumor from distal obstructive inflammation, so the GTV and MTV shown are larger than the true size of the tumor. In the coronal PET/CT fusion image (c) the high metabolic area exceeds the boundary of the tumor, indicating that there is a deviation in the matching between PET and CT. PET / MR: T2WI (d) can distinguish tumors from obstructive inflammation, and the lesions shown are smaller than CT. PET/MR fusion image (e, f) shows that the high metabolic area is located within the tumor boundary and matching accurate. At the same time, the range of the high metabolic area is smaller than the mass range shown in the T2WI, which indicates that there is a compressive atelectasis around the mass, and makes the tumor more accurate positioning.