Simultaneously occurring malignancies may be detected in different organs or tissues at any given time. Patients diagnosed with a tumor may be found to have another tumor or second primary cancer. Second primary cancers (SPCs) may be further classified as synchronous or metachronous. Synchronous SPCs are lesions detected simultaneously or within 6 months after the diagnosis of the primary tumor while metachronous SPCs are tumors diagnosed 6 months after primary tumor diagnosis.1There is an increased risk of having second primary cancer in Head and Neck Squamous Cell Carcinoma (HNSCC) patients.1 In a study by Strojan et al. in 2013, among 2,106 head and neck cancer patients, 2.4% developed synchronous second primary cancers.2 A systematic review by Coco-Pelaz et al. in 2020, showed that second primary tumors most frequently occur in the head and neck area followed by the lungs and esophagus.3We present a case of follicular thyroid carcinoma with an incidental finding of cervical lymph-node metastatic squamous cell carcinoma from the tonsil and discuss the clinical presentation, ancillary procedures and management.
Adenocarcinoma, Follicular ; Positron-Emission Tomography

18F-Fluorodeoxyglucose (18F-FDG) PET/CT scan is a vital imaging modality in the majority of oncologic situations. It is proven useful in staging, management and monitoring of lymphomas. Numerous subtypes of lymphomas exist; however, we present the first documented case of a 56-year-old, Filipino, male patient who is diagnosed with mantle cell lymphoma of the conjunctiva (MCL). MCL is an extremely rare type of extranodal non-Hodgkin lymphoma and has an aggressive nature with an estimated incidence of 2-4/1,000,000. This case highlights the critical role that PET/CT scans play in directing treatment decisions and monitoring the response of conjunctival MCL to therapy.
Lymphoma, Non-hodgkin ; Positron-emission Tomography

OBJECTIVE: To study the clinical, imaging, and pathological features of pulmonary lymphoma. METHODS: Patients with pulmonary lymphoma diagnosed by lung biopsy in Zhongda Hospital Affiliated to Southeast University from November 2013 to December 2020 were collected and divided into secondary pulmonary lymphoma (SPL) group and primary pulmonary lymphoma (PPL) group according to the primary site of lymphoma. The clinical characteristics, stages, imaging features, diagnostic methods and pathological types of the two groups were analyzed. RESULTS: A total of 22 patients were included, 10 cases were PPL and 12 cases were SPL. The main symptoms of the two groups were cough, dyspnea and chest pain. The proportion of stage III/IV patients and international prognostic index (IPI) in SPL group were significantly higher than those in PPL group (P<0.05). Chest high-resolution computed tomography (HRCT) mainly showed masses, nodules and consolidation in both groups. The proportions of single mass and air bronchial sign in PPL group were significantly higher than those in SPL group, while the proportions of multiple nodules, mediastinal/hilar lymphadenopathy and pleural effusion were significantly lower (P<0.05). The max standardized uptake value (SUV_max), peak standardized uptake value (SUV_peak), total lesion glycolysis (TLG) and metabolic tumor volume (MTV) of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in PPL group were lower than those in SPL group, but the differences were not statistically significant (P>0.05). In PPL group, 8 cases were diagnosed by transbronchial lung biopsy (TBLB) and 2 cases by percutaneous lung puncture. In SPL group, 4 cases were diagnosed by TBLB, 7 cases by percutaneous lung puncture, and 1 case by surgery. 95.5% patients were diagnosed by non-surgical methods. The main pathological type of PPL was mucosa-associated lymphoid tissue (MALT) lymphoma, while that of SPL was diffuse large B-cell lymphoma (P<0.05). CONCLUSION The clinical symptoms of pulmonary lymphoma are nonspecific, but the chest HRCT has characteristic manifestations, which can also help to distinguish between SPL and PPL. ¹⁸F-FDG PET/CT is also a potential method to distinguish between SPL and PPL. TBLB and percutaneous lung puncture biopsy are reliable methods for the diagnosis of lung lymphoma. The main pathological type of PPL is MALT lymphoma, while that of SPL is diffuse large B-cell lymphoma.
Humans ; Positron Emission Tomography Computed Tomography ; Fluorodeoxyglucose F18 ; Lung Neoplasms/pathology* ; Lymphoma, Large B-Cell, Diffuse/pathology* ; Lymphoma, B-Cell, Marginal Zone/diagnosis* ; Prognosis ; Retrospective Studies

OBJECTIVE: Current mainstream PET scattering correction methods are introduced and evaluated horizontally, and finally, the existing problems and development direction of scattering correction are discussed. METHODS: Based on NeuWise Pro PET/CT products of Neusoft Medical System Co. Ltd. , the simulation experiment is carried out to evaluate the influence of radionuclide distribution out of FOV (field of view) on the scattering estimation accuracy of each method. RESULTS: The scattering events produced by radionuclide out of FOV have an obvious impact on the spatial distribution of scattering, which should be considered in the model. The scattering estimation accuracy of Monte Carlo method is higher than single scatter simulation (SSS). CONCLUSIONS Clinically, if the activity of the adjacent parts out of the FOV is high, such as brain, liver, kidney and bladder, it is likely to lead to the deviation of scattering estimation. Considering the Monte Carlo scattering estimation of the distribution of radionuclide out of FOV, it's helpful to improve the accuracy of scattering distribution estimation.
Positron Emission Tomography Computed Tomography ; Scattering, Radiation ; Computer Simulation ; Brain ; Monte Carlo Method ; Phantoms, Imaging ; Image Processing, Computer-Assisted

A case of IgG4-related disease presented with a duodenal ulcer to improve the understan-ding of IgG4-related diseases was reported. A 70-year-old male presented with cutaneous pruritus and abdominal pain for four years and blackened stools for two months. Four years ago, the patient went to hospital for cutaneous pruritus and abdominal pain. Serum IgG4 was 3.09 g/L (reference value 0-1.35 g/L), alanine aminotransferase 554 U/L (reference value 9-40 U/L), aspartate aminotransferase 288 U/L (reference value 5-40 U/L), total bilirubin 54.16 μmol/L (reference value 2-21 μmol/L), and direct bilirubin 29.64 μmol/L (reference value 1.7-8.1 μmol/L) were all elevated. The abdominal CT scan and magnetic resonance cholangiopancreatography indicated pancreatic swelling, common bile duct stenosis, and secondary obstructive dilation of the biliary system. The patient was diagnosed with IgG4-related disease and treated with prednisone at 40 mg daily. As jaundice and abdominal pain improved, prednisone was gradually reduced to medication discontinuation. Two months ago, the patient developed melena, whose blood routine test showed severe anemia, and gastrointestinal bleeding was diagnosed. The patient came to the emergency department of Beijing Hospital with no improvement after treatment in other hospitals. Gastroscopy revealed a 1.5 cm firm duodenal bulb ulcer. After treatment with omeprazole, the fecal occult blood was still positive. The PET-CT examination was performed, and it revealed no abnormality in the metabolic activity of the duodenal wall, and no neoplastic lesions were found. IgG4-related disease was considered, and the patient was admitted to the Department of Rheumatology and Immunology of Beijing Hospital for further diagnosis and treatment. The patient had a right submandibular gland mass resection history and diabetes mellitus. After the patient was admitted to the hospital, the blood test was reevaluated. The serum IgG4 was elevated at 5.44 g/L (reference value 0.03-2.01 g/L). Enhanced CT of the abdomen showed that the pancreas was mild swelling and was abnormally strengthened, with intrahepatic and extrahepatic bile duct dilation and soft tissue around the superior mesenteric vessels. We pathologically reevaluated and stained biopsy specimens of duodenal bulbs for IgG and IgG4. Immunohistochemical staining revealed remarkable infiltration of IgG4-positive plasma cells into duodenal tissue, the number of IgG4-positive cells was 20-30 cells per high-powered field, and the ratio of IgG4/IgG-positive plasma cells was more than 40%. The patient was treated with intravenous methylprednisolone at 40 mg daily dosage and cyclophosphamide, and then the duodenal ulcer was healed. IgG4 related disease is an immune-medicated rare disease characterized by chronic inflammation and fibrosis. It is a systemic disease that affects nearly every anatomic site of the body, usually involving multiple organs and diverse clinical manifestations. The digestive system manifestations of IgG4-related disease are mostly acute pancreatitis and cholangitis and rarely manifest as gastrointestinal ulcers. This case confirms that IgG4-related disease can present as a duodenal ulcer and is one of the rare causes of duodenal ulcers.
Aged ; Humans ; Male ; Abdominal Pain/drug therapy* ; Acute Disease ; Bilirubin ; Duodenal Ulcer/etiology* ; Immunoglobulin G ; Immunoglobulin G4-Related Disease/diagnosis* ; Pancreatitis/drug therapy* ; Positron Emission Tomography Computed Tomography ; Prednisone/therapeutic use* ; Pruritus/drug therapy*

The American Urological Association (AUA), European Association of Urology (EUA) and International Urological Society (SIU) annual meetings were held in 2022. Studies on prostate cancer reported in the meetings mainly focus on the advances of diagnostic biomarkers (such as α-2, 3-1inked sialylation of terminal N-glycan on free PSA density, SelectMDx) and imaging techniques [such as multiparametric magnetic resonance imaging, prostate specific membrane antigen(PSMA)-PET/CT], the new method for prostate biopsy, the new treatments of prostate cancer including [¹⁷⁷Lu] Ludotadipep and DROP-IN PSMA probe, and the prognosis assessment of prostate cancer (such as AR-V7). This article provides an overview on the research hotspots of three international academic meetings.
Male ; Humans ; Urology ; Positron Emission Tomography Computed Tomography/methods* ; Prostatic Neoplasms/pathology* ; Multiparametric Magnetic Resonance Imaging/methods* ; Gallium Radioisotopes

Biology-guided radiotherapy (BgRT) is a novel technique of external beam radiotherapy, combining positron emission tomography-computed tomography (PET-CT) with a linear accelerator (LINAC). The key innovation is to utilize PET signals from tracers in tumor tissues for real-time tracking and guiding beamlets. Compared with a traditional LINAC system, a BgRT system is more complex in hardware design, software algorithm, system integration and clinical workflow. RefleXion Medical has developed the world's first BgRT system. Nevertheless, its actively advertised function, PET-guided radiotherapy, is still in the research and development phase. In this review study, we presented a number of issues related to BgRT, including its technical advantages and potential challenges.
Positron Emission Tomography Computed Tomography ; Radiotherapy Planning, Computer-Assisted/methods* ; Algorithms ; Particle Accelerators ; Biology ; Radiotherapy, Image-Guided/methods* ; Radiotherapy Dosage

Malignant liver tumors have a high incidence and mortality rate. Therefore, it is of great significance to promptly learn about tumor advancement status through relevant examinations for patients' follow-up, diagnosis, and therapy as well as the improvement of the five-year survival rate. The primary lesions and intrahepatic metastases of malignant liver tumors have been better demonstrated in the clinical study with the use of various isotope-labeled fibroblast activating protein inhibitors because of their low uptake in liver tissues and high tumor/background ratio, which provides a new method for early diagnosis, precise staging, and radionuclide therapy. In light of this context, a review of the research progress of fibroblast-activating protein inhibitors for the diagnosis of liver malignant tumors is presented.
Humans ; Positron Emission Tomography Computed Tomography ; Carcinoma, Hepatocellular ; Liver Neoplasms

OBJECTIVE: To explore the diagnostic value of ¹⁸F-FDG PET/CT in bone marrow infiltration (BMI) of newly diagnosed diffuse large B-cell lymphoma (DLBCL), compared with the results of bone marrow biopsy (BMB) and investigate whether the BMI diagnosed by ¹⁸F-FDG PET/CT and other factors have independent prognostic values. METHODS: Ninety-four newly diagnosed DLBCL patients who underwent PET/CT in Clinical Medical College of Shanghai General Hospital of Nanjing Medical University were included. BMB was performed within 2 weeks before or after PET/CT, and standardized treatment was performed after PET/CT. The manifestations of bone marrow (BM) FDG uptake were recorded. The diagnostic criteria of BMI were BMB positive or focal BM FDG uptake confirmed by imaging follow-up. The relationship between clinical features and BM FDG uptake and the values of PET/CT and BMB in the diagnosis of BMI was analyzed. The progression-free survival (PFS) was analyzed by Kaplan-Meier survival curves, log-rank test was used to compare PFS rate, and Cox regression model was used to analyze the independent risk factors affecting PFS. RESULTS: Among 94 DLBCL patients, 34 patients showed focal BM uptake (fPET), 7 patients showed super BM uptake (sBMU), 11 patients showed diffuse homogenous uptake higher than liver (dPET), and the other 42 patients had normal BM uptake (nPET) (lower than liver). BMB positive was found in all sBMU patients, in 20.6%(7/34) of fPET patients, and in 27.3% (3/11) of dPET patients. All nPET patients had negative BMB results. dPET patients were associated with lower hemoglobin level and leukocyte count compared with nPET group (P < 0.001, P =0.026). Compared with fPET patients, sBMU patients were more likely to have B symptoms and elevated lactate dehydrogenase (LDH). A total of 44 patients were diagnosed BMI, including 17 cases with BMB⁺. The sensitivity and specificity of BMB in the diagnosis of BMI was 38.6% (17/44) and 100% (50/50), respectively. Using fPET and sBMU as criteria of PET BMI, the diagnostic sensitivity and specificity of PET/CT was 93.2% (41/44) and 100% (50/50), respectively. Kaplan-Meier analysis showed that there was no significant difference in 2-year PFS rate between nPET and dPET patients (P >0.05), while sBMU patients had lower 2-year PFS rate compared with fPET patients (P < 0.001). Multivariate analysis showed that higher Ann Arbor stage (HR=9.010, P =0.04) and sBMU (HR=3.964, P =0.002) were independent risk factors affecting PFS. CONCLUSIONS Increased BM FDG uptake of DLBCL can be manifested as dPET, fPET and sBMU. fPET and sBMU can replace BMB to diagnose BMI. Although dPET cannot completely exclude the possibility of BMI, it does not affect the prognosis, so it can be diagnosed as PET BMI negative. sBMU is an independent prognostic risk factor.
Humans ; Positron Emission Tomography Computed Tomography/methods* ; Fluorodeoxyglucose F18 ; Prognosis ; Bone Marrow/pathology* ; Retrospective Studies ; China ; Positron-Emission Tomography/methods* ; Lymphoma, Large B-Cell, Diffuse/pathology* ; Biopsy

OBJECTIVE: To investigate the correlation between ¹⁸Fluoro-deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) metabolic parameters and peripheral blood circulating tumour DNA (ctDNA) in patients with diffuse large B-cell lymphoma (DLBCL), and the prognostic value of these two types of parameters in predicting progression-free survival (PFS). METHODS: Clinical, PET/CT and ctDNA data of DLBCL patients who underwent peripheral blood ctDNA testing and corresponding PET/CT scans during the same period were retrospectively analyzed. At the time of ctDNA sampling and PET scan, patients were divided into baseline and relapsed/refractory (R/R) groups according to different disease conditions. CtDNA mutation abundance was expressed as variant allele frequency (VAF), including maximum VAF (maxVAF) and mean VAF (meanVAF). Total metabolic tumour volume (TMTV) and total lesion glycolysis (TLG) were obtained by the 41% maximum normalized uptake value method, and the distance between the two farthest lesions (Dmax) was used to assess the correlation between PET parameters and ctDNA mutation abundance using Spearman correlation analysis. The receiver operating characteristic (ROC) curves were used to obtain the optical cut-off values of those parameters in predicting PFS in the baseline and R/R groups, respectively. Survival curves were outlined using the Kaplan-Meier method and log-rank test was performed to compare survival differences. RESULTS: A total of 67 DLBCL patients ［28 males and 39 females, median age 56.0(46.0, 67.0) years］ were included and divided into baseline group (29 cases) and R/R group (38 cases). Among these PET parameters, baseline TMTV, TLG, and Dmax were significantly correlated with baseline ctDNA mutation abundance, except for maximum standardized uptake value (SUVmax) (maxVAF vs TMTV: r=0.711; maxVAF vs TLG: r=0.709; maxVAF vs Dmax: r=0.672; meanVAF vs TMTV: r=0.682; meanVAF vs TLG: r=0.677; meanVAF vs Dmax: r=0.646). While in all patients, these correlations became weaker significantly. Among R/R patients, only TMTV had a weak correlation with meanVAF (r=0.376). ROC analysis showed that, the specificity of TMTV, TLG and Dmax in predicting PFS was better than mutation abundance, while the sensitivity of ctDNA mutation abundance was better. Except R/R patients, TMTV, TLG, Dmax, and VAF were significantly different at normal/elevated lactate dehydrogenase in baseline group and all patients (all P<0.05). Survival curves indicated that high TMTV (>109.5 cm³), high TLG (>2 141.3), high Dmax (>33.1 cm) and high VAF (maxVAF>7.74%, meanVAF>4.39%) were risk factors for poor PFS in baseline patients, while only high VAF in R/R patients (both maxVAF and meanVAF >0.61%) was a risk factor for PFS. CONCLUSION PET-derived parameters correlate well with ctDNA mutation abundance, especially in baseline patients. VAF of ctDNA predicts PFS more sensitively than PET metabolic parameters, while PET metabolic tumour burden with better specificity. TMTV, TLG and VAF all have good prognostic value for PFS. PET/CT combined with ctDNA has potential for further studies in prognostic assessment and personalized treatment.
Male ; Female ; Humans ; Middle Aged ; Positron Emission Tomography Computed Tomography ; Fluorodeoxyglucose F18 ; Circulating Tumor DNA/genetics* ; Retrospective Studies ; Positron-Emission Tomography ; Survival Analysis ; Lymphoma, Large B-Cell, Diffuse/metabolism* ; Prognosis