How much exposure dose does a patient receive in PET/CT examination? / 中国辐射卫生

@#Positron emission tomography/computed tomography (PET/CT) scanner is an irreplaceable instrument in clinical diagnosis. The exposure dose that a patient receives is the sum of the doses caused by PET and CT examination. This study discussed the exposure dose level that a patient received during PET/CT examination according to the research data. Like other radiological diagnostic methods, PET/CT examination brings benefits outweighing its radiation risk. It is not advisable to exaggerate or ignore the exposure dose. The patient’s exposure dose caused by PET/CT examination should be controlled as much as possible under the premise of meeting clinical needs.

Progress in application of positron emission tomography/computed tomography (PET/CT) imaging in tumor screening / 中国辐射卫生

@#Worldwide, the incidence of cancer is greatest in China. Tumor screening is effective to achieve early diagnosis, improve prognosis, increase the quality of life, and reduce mortality among cancer patients. Positron emission tomography/computed tomography (PET/CT) imaging provides metabolic data to support initial staging, treatment planning, and response evaluation in tumor screening, as well as tumor follow-up. The progressive integration of PET/CT imaging in radiotherapy has its basic principle in the biological heterogeneity of inter- and intra-tumor malignant lesions, and the radiation dose is required to be adjusted to achieve effective local tumor control among cancer patients. In addition, PET/CT imaging provides data on the biological features of tumor lesions, such as metabolism, hypoxia, and proliferation, which is useful to identify radiation-resistant regions and optimize treatment plans. These data are effective to reduce the uncertainty and variability in the anatomic description of tumor sites. This review summarizes the application of PET/CT imaging in common tumors.

Application of 18F-FDG PET/CT-guided percutaneous biopsy to differential diagnosis of peritoneal thickening diseases / 上海交通大学学报（医学版）

Objective • To investigate the clinical value of 18F-flurodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/ CT)-guided percutaneous biopsy in peritoneal thickening of unknown origin. Methods • Ten cases of peritoneal thicken of unknown origin including 4 males and 6 females were analyzed. After 18F-FDG PET/CT examination, the peritoneal thickening regions with high 18F-FDG uptake were selected for the target areas. Percutaneous biopsy was operated under the guidance of the same PET/CT machine. Results • All lesions were successfully obtained by one-time puncture without serious complications, and histopathological diagnosis revealed that 7 cases were malignant, including 4 cases of peritoneal metastasis and 3 cases of lymphoma. The remaining cases were 1 case of pseudomyxoma, 1 case of tuberculosis and 1 case of inflammatory lesions. The accuracy of biopsy was 100%. Conclusion • 18F-FDG PET/CT-guided peritoneal percutaneous biopsy is a safe and effective method, and may play an important role in differential diagnosis and treatment management.

Cancer Metabolism as a Mechanism of Treatment Resistance and Potential Therapeutic Target in Hepatocellular Carcinoma

Various molecular targeted therapies and diagnostic modalities have been developed for the treatment of hepatocellular carcinoma (HCC); however, HCC still remains a difficult malignancy to cure. Recently, the focus has shifted to cancer metabolism for the diagnosis and treatment of various cancers, including HCC. In addition to conventional diagnostics, the measurement of enhanced tumor cell metabolism using F-18 fluorodeoxyglucose (18F-FDG) for increased glycolysis or C-11 acetate for fatty acid synthesis by positron emission tomography/computed tomography (PET/CT) is well established for clinical management of HCC. Unlike tumors displaying the Warburg effect, HCCs vary substantially in terms of 18F-FDG uptake, which considerably reduces the sensitivity for tumor detection. Accordingly, C-11 acetate has been proposed as a complementary radiotracer for detecting tumors that are not identified by 18F-FDG. In addition to HCC diagnosis, since the degree of 18F-FDG uptake converted to standardized uptake value (SUV) correlates well with tumor aggressiveness, 18F-FDG PET/CT scans can predict patient outcomes such as treatment response and survival with an inverse relationship between SUV and survival. The loss of tumor suppressor genes or activation of oncogenes plays an important role in promoting HCC development, and might be involved in the “metabolic reprogramming” of cancer cells. Mutations in various genes such as TERT, CTNNB1, TP53, and Axin1 are responsible for the development of HCC. Some microRNAs (miRNAs) involved in cancer metabolism are deregulated in HCC, indicating that the modulation of genes/miRNAs might affect HCC growth or metastasis. In this review, we will discuss cancer metabolism as a mechanism for treatment resistance, as well as an attractive potential therapeutic target in HCC.

Contralateral Internal Mammary Lymphadenopathy Mimicking Metastasis in a Patient with a History of Breast Cancer and Prior Interstitial Mammoplasty by Paraffin Injection: MRI, PET-CT, and Pathological Findings

Foreign body injections into breasts may produce foreign body reactions, fibrosis, and local swelling of involved lymph nodes, which can be misdiagnosed as metastasis or malignancy. Here, the authors report MR imaging, PET-CT imaging, and pathologic findings of contralateral internal mammary lymphadenopathy suspicious of breast cancer metastasis in a 58-year-old woman with history of left breast cancer, and previous interstitial mammoplasty by paraffin injection in both breasts.

Optimal Threshold of Stimulated Serum Thyroglobulin Level for 18F-FDG PET/CT imaging in Patients with Thyroid Cancer / 华中科技大学学报（医学）（英德文版）

This study was to explore the optimal threshold of thyroid-stimulating hormone (TSH)-stimulated serum thyroglobulin (s-Tg) for patients who were to receive 18F-fluorodeoxyglucose (18F-FDG) PET/CT scan owing to clinical suspicion of differentiated thyroid cancer (DTC) recurrence but negative post-therapeutic 131I whole-body scan (131I-WBS).A total of 60 qualified patients underwent PET/CT scanning from October 2010 to July 2014.The receiver operating characteristic (ROC) curve analyses showed that s-Tg levels over 49 μg/L led to the highest diagnostic accuracy of PET/CT to detect recurrence,with a sensitivity of 89.5％ and a specificity of 90.9％.Besides,bivariate correlation analysis showed positive correlation between s-Tg levels and the maximum standardized uptake values (SUVmax) of 18F-FDG in patients with positive PET/CT scanning,suggesting a significant influence of TSH both on Tg release and uptake of 18F-FDG.So,positive PET/CT imaging is expected when patients have negative 131I-WBS but s-Tg levels over 49 μg/L.

Quality Control of the Research on Mechanisms of Acupuncture Therapy by Using PET-CT Imaging Techniques / 针刺研究

Combining the functional metabolic imaging and anatomical imaging,PET-CT stands for the highest level of current nuclear medical imaging techniques,and has been applying increasingly in acupuncture studies.However,owning to complexity of the brain function and sensitivity of brain metabolism,the lower reproducibility of cerebral function imaging even may reverse many results.This has been provoked more and more attention by researchers.Its main cause is intimately related to poor experimental methodology.For this reason,the present paper raises the quality control of the research on mechanisms of acupuncture in the process of application of PET-CT techniques from 1) the included standards of participants,2) the preparation of participants during the scanning process of PET-CT,3) the setting of the scanning parameters,4) the used machine and the imaging reagent,5) the analysis of dada,6) the standardization of acupuncture manipulation,and 7) the designs of the acupuncture operation,needling opportunity and scanning opportunity,hoping to offer some beneficial information for the coming researches.