As technologies are progressing rapidly in many aspects, microPET has been developing worldwide at present. The principle, up-to-date status and development of microPET, as well as its existing problems which should be solved, have been introduced in this paper.
Positron-Emission Tomography ; methods ; trends

BACKGROUNDDiagnosis of syphilis is difficult. Follow-up and therapy evaluation of syphilitic patients are poor. Little is known about positron emission tomography (PET) in syphilis. This review was to systematically review usefulness of PET for diagnosis, disease extent evaluation, follow-up, and treatment response assessment in patients with syphilis.

METHODSWe searched PubMed, EMBASE, SCOPUS, Cochrane Library, Web of Science, ClinicalTrials.gov, and three Chinese databases (SinoMed, Wanfang, and CNKI) for English and Chinese language articles from inception to September 2016. We also collected potentially relevant studies and reviews using a manual search. The search keywords included the combined text and MeSH terms "syphilis" and "positron emission tomography". We included studies that reporting syphilis with a PET scan before and/or after antibiotic treatment. The diagnosis of syphilis was based on serological criteria or dark field microscopy. Outcomes include pre- and post-treatment PET scan, pre- and post-treatment computed tomography, and pre- and post-treatment magnetic resonance imaging. We excluded the articles not published in English or Chinese or not involving humans.

RESULTSOf 258 identified articles, 34 observational studies were included. Thirty-three studies were single-patient case reports and one study was a small case series. All patients were adults. The mean age of patients was 48.3 ± 12.1 years. In primary syphilis, increased fluorodeoxyglucose (FDG) accumulation could be seen at the site of inoculation or in the regional lymph nodes. In secondary syphilis with lung, bone, gastrointestinal involvement, or generalized lymphadenopathy, increased FDG uptake was the most commonly detected changes. In tertiary syphilis, increased glucose metabolic activity, hypometabolic lesions, or normal glucose uptake might be seen on PET. There were five types of PET scans in neurosyphilis. A repeated PET scan after treatment revealed apparent or complete resolution of the asymmetry of radiotracer uptake.

CONCLUSIONPET is helpful in targeting diagnostic interventions, characterizing disease extent, assessing nodal involvement, and treatment efficacy for syphilis.

OBJECTIVETo propose a new method for dynamic positron emission tomographic (PET) image reconstruction using low rank and sparse penalty (L&S).

METHODSThe L&S reconstruction model was established and the split Bregman method was used to solve the optimal cost function. The one-tissue compartment model was used to simulate a set of PET 82Rb myocardial perfusion image. The L&S reconstruction method was compared with maximum likelihood expectation maximization (MLEM) method, low-rank penalty method and sparse penalty method.

RESULTSThe L&S reconstruction method had the smallest MSE and well maintained the feature information. The polar map created by L&S method was the most similar with the reference actual polar map.

CONCLUSIONL&S reconstruction method is better than the other three methods in both visual and quantitative analysis of the PET images.

Numerous methods to segment tumors using ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) have been introduced. Metabolic tumor volume (MTV) refers to the metabolically active volume of the tumor segmented using FDG PET, and has been shown to be useful in predicting patient outcome and in assessing treatment response. Also, tumor segmentation using FDG PET has useful applications in radiotherapy treatment planning. Despite extensive research on MTV showing promising results, MTV is not used in standard clinical practice yet, mainly because there is no consensus on the optimal method to segment tumors in FDG PET images. In this review, we discuss currently available methods to measure MTV using FDG PET, and assess the advantages and disadvantages of the methods.
Consensus ; Electrons ; Humans ; Methods ; Positron-Emission Tomography ; Radiotherapy ; Tumor Burden

PURPOSE: To compare the performance of fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) with conventional imaging methods (CIM), including computed tomography (CT), magnetic resonance imaging (MRI), and mammography (MMG) in cancer of unknown primary (CUP).METHODS: A total of 36 patients with CUP, who referred to our clinic for a FDG PET/CTscan, were enrolled in this study. Thirty of the patients were also examined through either diagnostic CT/MRI and/or MMG. The diagnostic performance of both methods for the primary cancer location was analyzed. The results of FDG PET/CT and CIM were compared based on the standard reference of the histopathology and/or clinical and laboratory follow-up.RESULTS: The primary cancer locations were detected in 24 patients (66.6%, 24/36) by FDG PET/CT, whereas CIM identified the locations in 16 patients (53.3%, 16/30). Sensitivity, specificity, PPV, NPV, and accuracy rates of the detection of the primary tumor localizations were as follows: 83, 70, 89, 58, and 79% for FDG PET/CT; 70, 62, 84, 42, and 68% for CIM, respectively. There was no statistical significance between modalities regarding any of the categories in 30 patients.CONCLUSION: FDG PET/CT detected the primary tumors of the patients with CUP more than CIM did. However, the difference between them was not found to be statistically significant. It may be considered that FDG PET/CT scan can be performed as a first-line tool in the initial diagnosis of the patients with CUP and to add radiodiagnostic imaging in selective cases.We conclude that if the first-line examination of a CUP patient has been already performed by a CIM and the result was negative or inconclusive, FDG PET/CT can be considered to avoid unnecessary imaging procedures.
Diagnosis ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Mammography ; Methods ; Positron-Emission Tomography ; Positron-Emission Tomography and Computed Tomography ; Sensitivity and Specificity

Prostate cancer is the most common malignant tumor in male urinary system, and the morbidity and mortality rate are increasing year by year. Traditional imaging examinations have some limitations in the diagnosis of prostate cancer, and the advent of molecular imaging probes and imaging technology have provided new ideas for the integration of diagnosis and treatment of prostate cancer. In recent years, prostate-specific membrane antigen (PSMA) has attracted much attention as a target for imaging and treatment of prostate cancer. PSMA ligand positron emission tomography (PET) has important reference value in the diagnosis, initial staging, detection of biochemical recurrence and metastasis, clinical decision-making guidance and efficacy evaluation of prostate cancer. This article briefly reviews the clinical research and application progress on PSMA ligand PET imaging in prostate cancer in recent years, so as to raise the efficiency of clinical applications.
Male ; Humans ; Prostate/pathology* ; Ligands ; Positron Emission Tomography Computed Tomography/methods* ; Prostatic Neoplasms/diagnostic imaging* ; Positron-Emission Tomography

Occupational pneumoconiosis is one of the main occupational diseases in China. Progressive massive fibrosis in pneumoconiosis should be distinguished from lung cancer for their similar imaging features which is often identified by (18)F-FDG PET-CT in clinic. Here we reported two cases of pneumoconiosis. Both of them were suspected of carrying malignant tumors by preoperative PET-CT exam, however, nodules in these two patients were all proved to be benign by intraoperative pathology which suggested that there is false-positive possibility in the distinguishment of pneumoconiosis nodules by (18)F-FDG PET-CT.
Fibrosis ; Fluorodeoxyglucose F18 ; Humans ; Lung Neoplasms/pathology* ; Pneumoconiosis/pathology* ; Positron Emission Tomography Computed Tomography ; Positron-Emission Tomography/methods*

The applications of PET-CT have developed from qualitative analysis to quantitative analysis. Target volume is important for tumor biological volume defining, tumor isotope therapy, organ function evaluation, acceptor affinity calculation, and pharmaceutical metabolic kinetics. Many factors work on the target volume calculation, such as PET image acquisition mode, scatter correction, attenuation correction, reconstruction method, image display mode, positron pharmacy. The commonly-used methods of target volume calculation are background-threshold, max threshold, and background-max threshold. In this article we will discuss about the methods of target volume calculation.
Algorithms ; Positron-Emission Tomography ; methods ; Radiotherapy Planning, Computer-Assisted ; methods ; Tomography, X-Ray Computed ; methods

This paper introduced the imaging principle, data acquisition method and image characteristics of PET/CT; Then reviewed several image reconstruction methods widely used in PET/CT at present in detail, such as FBP, ML-EM, 3DRP and so on. Finally, the advantages and disadvantages of these methods were summarized and compared.
Image Interpretation, Computer-Assisted ; methods ; Positron-Emission Tomography ; methods ; Tomography, X-Ray Computed ; methods

Fluorodeoxyglucose F18 ; Humans ; Lymphoma ; diagnostic imaging ; Positron-Emission Tomography ; methods ; Tomography, X-Ray Computed ; methods