ABSTRACT
Objective:To investigate the capability of 18F-FDG PET/CT imaging in monitoring combined immunotherapy response and detecting immune related adverse events (irAEs) in patients with advanced hepatobiliary carcinoma. Methods:From August 2018 to July 2019, 21 patients (14 males, 7 females, age (58.5±10.0) years) with advanced hepatobiliary carcinoma routinely underwent 66 18F-FDG PET/CT examinations in Peking Union Medical College Hospital. SUV max, the occurrence time and symptoms of irAEs were obtained and analyzed. Therapy response (complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), progressive metabolic disease (PMD)) was evaluated according to PET response criteria in solid tumors (PERCIST). Results:(1) Clinical results. Twenty-two irAEs occurred in 16 patients, while were not found in 5 patients. Six organs were involved, including thyroiditis(8), colitis(5), pneumonitis(4), rash(2), hepatitis(2), myositis and fasciitis(1). The appearance time of each irAEs were (103.0±58.0), (141.6±103.5), 34.0(6.0, 308.8), 9 and 117, 62 and 67, and 87 d after therapy, respectively. PET/CT detected all pneumonitis and myositis and fasciitis, but no rash and hepatitis were found. For colitis and thyroiditis, PET/CT detected 4 and 6 times respectively. (2) PET/CT signs of irAEs. Except thyroiditis, all irAEs lesions exhibited exudative changes in CT and high-avidity in PET. SUV max of the lesions were 9.0(7.9, 17.6) (colitis), 7.1±3.2 (thyroiditis), 5.3 and 8.6 (pneumonitis), 4.1 (myositis and fasciitis), respectively. (3) Therapy assessment. Among 21 patients, there were 7 for PMR, 9 for SMD, 5 for PMD, which were 7, 8, 1 in patients with irAEs and 0, 1, 4 in patients without irAEs. Conclusions:Patients with advanced hepatobiliary carcinoma can benefit from combined immunotherapy. 18F-FDG PET/CT can be used to evaluate the efficacy of immunotherapy by detecting the changes of tumor lesions and the occurrence of irAEs simultaneously. However, it is necessary to use CT to distinguish tumor progression from irAEs.
ABSTRACT
Objective To retrospectively study the biodistribution of 68Ga-DOTA-TATE as a SSTR imaging agent in human subjects.Methods A total of 106 patients with suspected disease were enrolled in this study.All patients were histologically proven for having either a single tumor ＜2 cm or without evidence of tumor during follow-up.Patients underwent PET/CT whole-body scan 17-100 min after intravenous injection of 55.2-220.0 MBq 68Ga-DOTA-TATE.ROI was drawn for measuring SUV of tracer-avid pathologies.One-way analysis of variance and two-sample t test were used for statistical analysis.Results High 68Ga-DOTA-TATE avidity was found in pituitary,with SUVmax of 4.00± 1.21.Tracer was excreted mainly through urinary system resulting in highest uptake in the urinary tracts.The SUVmax of kidney cortex was 19.01 ± 5.45.Mediastinal blood pool and liver SUVmax were 0.93±0.33 and 7.69±2.26,respectively.Mild uptake of 68Ga-DOTA-TATE was found in the brain,cerebellum,lung and muscle,all lower than that of mediastinal blood pool.Moderate accumulation of 68 Ga-DOTA-TATE (close to or slightly higher than liver) was found in adrenal gland and spleen,with SUVmax 7.61 ± 3.42 and 8.63± 2.31,respectively.Other organs (pituitary,salivary gland,thyroid,pancreas,small intestine,colon,uterus,prostate and bone) showed tracer uptake in the range between those of mediastinal blood pool and liver.68Ga-DOTA-TATE distribution in pancreas was not uniform.Nine patients had focal accumulation in the uncinate process of pancreas with highest SUVm~ up to 8.48.However,the SUVmax and SUV in the rest of pancreas (head,neck,body and tail) showed insignificant difference (F values:0.703,0.563,both P＞0.05).68Ga-DOTA-TATE uptake in each organ reached equilibrium quickly after injection but with slight increase over time.The changes in SUV,however,showed insignificant difference among organs,including different parts of pancreas (t values:from -0.09 to 1.75,from-1.70 to-0.42,respectively,all P＞0.05).Conclusions The biodistribution of 68Ga-DOTA-TATE reaches equilibrium shortly after intravenous administration and is stably maintained.The biodistribution activities are organ-specific,and characteristic to that of SSTR concentration.
ABSTRACT
Objective To investigate the characteristics of NEN metastasis with SSTR PET/CT and to correlate the results with FDG-PET and pathology.Methods From November 2011 to August 2016,a total of 43 patients with NEN (18 males,25 females;age range:26-74 years) were recruited into this retrospective study;they underwent 68Ga-DOTA-TATE PET/CT (TATE-PET) imaging 40-60 min after 44.4-229.4 MBq 68Ga-DOTA-TATE administration.Metastases in 31 patients were confirmed by histopathology and in 12 patients by follow-up and other imaging modalities.Twenty-eight of 43 patients finished routine FDG-PET in a week after TATE-PET.PET/CT results were considered positive when the metastatic lesions were tracer-avid.ROI was drawn over each lesion for size and SUV measurement.x2 test and Pearson correlation analysis were used for statistical analysis.Results (1) Of 43 patients,TATE-PET detection rates of metastasis in the liver,lymph nodes,bones.and lungs were 85.7％(30/35),12/13,7/7,2/3,respectively,with their corresponding SUVmax of 18.1(11.3-23.3),10.8(5.4-15.6),7.7(4.2-9.9) and 1.8(1.3-2.3),respectively.Statistical correlation between size and SUVmax was found in metastatic bone lesions(r=0.233,P＜0.05).(2) In 31 patients with histopathologically proven metastasis,TATE-PET detected 23/24 (95.8％) G2,1/2 G1 and 5/5 G3 metastases.G1 metastases were only found in the liver.(3)Among 28 patients underwent both TATE-PET and FDG-PET,there was no significant difference between the detecting rate of metastasis:89.2％ (25/28) vs 71.4％ (20/28);x2 =2.389,P＞0.05.Compared with FDG-PET,TATE-PET was superior in demonstrating metastasis in the liver and bones (70.0％ (14/20) vs 65.0％ (13/20),3/3 vs 2/3),equal in detecting lung metastasis (both 2/3) but inferior in demonstrating metastasis in lymph nodes (9/10vs 10/10).Conclusions The capability of TATE-PET in revealing NEN metastasis varies depending on lesion localization and histologic grade.TATE-PET and FDG-PET are complementary to each other in detection of NEN metastasis,but without obvious relationship to histologic grade.