Part ? Multiple Time-point PET/CT Studies Performed After Oral Administration Of ¹⁸F-NaF Part ? Comparison Of PET/CT Performance After Oral And Intravenous Administration Of ¹⁸F-Fluoride

Objective : After oral administration of ¹⁸F-Na F,PET/CT studies performed at multiple time points.To observe the distribution of ¹⁸F-Na F and find the optimum point for bone imaging.Patients and Methods: 6 healthy volunteer?3 males,3 female;age ranged 38⁵2 years,median age 48 years?underwent local PET/CT studies at 0,10,20,30 and 40 minutes respectively after oral administration of ¹⁸F-Na F.Then the whole-body PET/CT studies performed at 60,120 and 180 minutes.All PET/CT images were reviewed,and the distribution of ¹⁸F-Na F in the body including the skeleton was observed.Drawing the ROIs?region of interest?of the heart blood pool,liver,sternum,C7 vertebral body,T7 vertebral body,L2 vertebral body and both of the calvicles and the humeri to calculate the SUVmax on PET/CTs at all points ranged from 0 to 180 minutes,drawing the points-SUVmax line chart for visual analysis.Drawing the ROIs of the body of sphenoid,sacrum,ulnae,radii,ischiatic tubers,tibias and fibulas to calculate the SUVmax on PET/CTs at 60,120 and 180 minutes,drawing the bar chart for visual analysis.Results:?1?Qualitative analysis.Skeletal imaging started at about 10²0minutes and became increasingly prominent over time.Axial skeleton displayed relatively fine at 40 minute.The PET/CT images at 60 minutes were sufficient for interpretation.The images at 120 and180 minutes had good quality.?2?Quantitative analysis.At all of the points,the highest tracer uptake level were in the vertebral bodies,followed by in the ischiatic tubers,sternum,caput femoris,caput humeri,body of sphenoid,lesser trochanter of femur,clavicls,femoral shafts,humeral shaft,ulnae,radii,tibias and fibulas.Conclusions: The axial skeletal started at about 10²0 minutes for imaging and the bones of the four limbs started at about 30⁴0 minutes.The PET/CT images at 60 minute after ¹⁸F-Na F oral administration could distinctly display the axial and pelvic bones.However,the delayed images at 120 and 180 minutes would be good for the interpretation for the bones of the four limbs,especially the ulnae,radii,tibias and fibulas.Objective: To investigate the possibility and diagnostic power of an ¹⁸F-Na F PET/CT bone scan after oral administration of the tracer by comparing the studies performed after oral and intravenous routes.Patients and Methods: Fifty patients?19 males,31females;age ranged 24⁷5 years,median age 52 years?with cancer were divided into two groups randomly,including fasting group and non-fasting group.All patients underwent ¹⁸F-Na F PET/CT scans after oral and intravenous administration respectively with an interval of 2⁷ days.Dual-phase ¹⁸F-Na F PET/CT was performed 60 minutes and 120 minutes after oral administration;single-phase ¹⁸F-Na F PET/CT was performed 60 minutes after intravenous administration.The patients of fasting group were asked to fast for 4⁶ hours before oral administration,the patients of non-fasting group were not.All of the other protocols were the same.All PET/CT images were reviewed,lesions on each image were counted,and SUVmax and T/NT values were obtained by manually drawing the region of interest?ROI?.Results: Forty-one patients?15 males,26females;age ranged 28⁷5 years,mean age 53.5±10.4 years,median age 52 years?were included our study.The number of positive cases in 41 patients from three modalities were the same.The positive cases were 35,including 25 cases of malignancy,8 of benignancy and 2 of ambiguity.Detection rate of positive and malignant cases were 61.0%?25/41?and 85.4%?35/41?respectively.The number of osseous lesions in 41 patients from three modalities were the same: a total of 302 lesions,including 172 malignant,108 benign and 22 ambiguous lesions.All of the 302 osseous lesions were included for SUVmax analysis.The SUVmax-oral60 min was lower than the corresponding SUV max-IV in the same lesion?18.22±12.64 and 28.07±16.34;Z=-14.47,P < 0.05?.The SUV max-oral120 min was slightly lower than the corresponding SUVmax-IV?26.60±19.49 and 28.07±16.34;Z=-5.22,P<0.05?.194 osseous lesions were included for T/NT value analysis.The difference between T/NT-oral 60min?2.87±1.50?and T/NT-IV?2.76±1.30?was not significant?Z=-2.32,P>0.05?,but T/NT-oral120min?2.98±1.42?was higher than the T/NT-IV?Z=-2.62,P<0.05?.Distribution of ¹⁸F-Na F in the digestive tract mainly located in the stomach and bowel.The difference of the digestive tract imaging between the fasting group and the non-fasting group was not significant.Conclusions: ¹⁸F-Na F PET/CT images after oral administration,especially,the 120 minute phase,had a similar diagnostic power of lesion-detection and SUVmax-measurement comparing to that of the intravenous route.