Co-registration and application of Positron Emission Tomography (PET), Computed Tomography (CT) as sompared with Magnetic Resonance Imaging (MRI) in target localization for undifferentiated Carcinoma of the Nasopharynx (NPC)

Purpose/Objective(s): Accurate target localization is always challenging in Intensity Modulated Radiation Therapy (IMRT). The use of multi-modality imaging tools is believed to improve the accuracy of target localization. The application of PET images for target localization is still preliminary and lacking consensus. In this study, we compare the tumor volumes of the primary site and neck nodes of NPC contoured on PET, CT and MRI images independently. Materials/Methods: 32 patients with newly diagnosed NPC treated with IMRT underwent incorporated PET/CT scan in the treatment position in a single session for planning purposes. 18F-fluorodeoxyglucose (FDG) and intravenous contrast were injected during PET and CT scans respectively. MRI scan was also performed without cast but with the position of the head and neck simulating the actual treatment position. The MRI images were then co-registered with the PET/CT images. Gross tumor volumes (GTV) of both the primary site (GTV-P) and the neck nodes (GTV-N) were contoured on the images of PET, CT and MRI independently by the same oncologist without cross-referencing. The window settings of PET images were fixed at 10000Bq/ml (width) and 0Bq/ml (length). The GTVs contoured on PET, CT, PET combined with CT (PET+CT) and MRI were analyzed and compared. Results: The mean volumes of GTV-P contoured on CT, PET, PET+CT and MRI were 22.81cm3, 24.49cm3, 30.30cm3 and 26.81cm3 respectively. The mean volumes of GTV-N on CT, PET, PET+CT and MRI were 20.37cm3, 22.50cm3, 29.09cm3 and 26.22cm3 respectively. Taking MRI as the gold standard, Pearson correlation revealed a strong correlation in the localization of GTV-P by different imaging tools: (1) MRI vs CT (r=0.990, p=0.000), (2) MRI vs PET (r=0.964, p=0.000) and (3) MRI vs PET+CT (r=0.979, p=0.000). Subgroup analysis stratified into advanced (T3 & T4, AJCC 2002) and early T-stage (T1, T2a & T2b, AJCC 2002) showed that high degrees of correlation for GTV-P were still maintained (MR vs CT, r=0.992, p=0.000; MR vs PET, r=0.969, p=0.000; and MR vs PET+CT, r=0.979, p=0.000). A high degree of correlation was also noted in GTV-N (MRI vs CT, r=0.976, p=0.000), (MRI vs PET, r=0.909, p=0.000) and (MR vs PET+CT, r=0.975, p=0.000). The minimum concentration of FDG in localizing both GTV-P (from 6800 to 7300 Bq/ml) and GTV-N (from 6800 to 7500 Bq/ml) were highly consistent and reproducible. Conclusions: The incorporation of PET scan into the standard MRI and CT co-registration is definitely feasible and helpful in tumor localization. Future efforts should be made to derive the most appropriate algorithm in contouring the GTV on PET images

The impact of time of day on energy expenditure: Implications for long-term energy balance

There is evidence to indicate that the central biological clock (i.e., our endogenous circadian system) plays a role in physiological processes in the body that impact energy regulation and metabolism. Cross-sectional data suggest that energy consumption later in the day and during the night is associated with weight gain. These findings have led to speculation that when, as well as what, we eat may be important for maintaining energy balance. Emerging literature suggests that prioritising energy intake to earlier during the day may help with body weight maintenance. Evidence from tightly controlled acute experimental studies indicates a disparity in the body’s ability to utilise (expend) energy equally across the day and night. Energy expenditure both at rest (resting metabolic rate) and after eating (thermic effect of food) is typically more efficient earlier during the day. In this review, we discuss the key evidence for a circadian pattern in energy utilisation and balance, which depends on meal timing. Whilst there is limited evidence that simply prioritising energy intake to earlier in the day is an effective strategy for weight loss, we highlight the potential benefits of considering the role of meal timing for improving metabolic health and energy balance. This review demonstrates that to advance our understanding of the contribution of the endogenous circadian system toward energy balance, targeted studies that utilise appropriate methodologies are required that focus on meal timing and frequenc

Multidisciplinary management of painful diabetic peripheral neuropathy: literature review and updated recommendation

Summary The management of painful diabetic peripheral neuropathy (DPN) requires a multidisciplinary approach, encompas sing both pharmacological and non-pharmacological treatment strategies. The Mul t idiscipl inar y Panel on Neuropathic Pain has publ ished recommendat ions on the management of painful DPN and provides here an update that emphasises the importance of good glycaemic control for all patients with diabetes, and includes newly published epidemiological studies and clinical evidence for the management of painful DPN. Based on published clinical evidence and international guidelines, first-line agents for DPN include α2δ-ligands, tricyclic antidepressants and selective serotonin-norepinephrine reuptake inhibitors. If a reasonable trial of a first-line agent does not relieve pain effectively, combination therapy with or switching to another first-line agent should be considered. Tramadol can be considered as a second-line treatment option. 摘要 糖尿病性末梢神經病變引起的疼痛，需由不同學科的醫 療團隊以藥物及非藥物方式進行治療。跨學科研究神經 病變性疼痛小組在最近發表治療糖尿病性末梢神經病變 的建議時，強調所有糖尿病患者在控制血糖水平的重要 性，並引述最新處理糖尿病末梢神經病變性疼痛的流行 病學研究和臨床實證。據已發表的臨床實證和國際指 引，治療糖尿病性末梢神經病變的第一線藥物包括α2δ- 配體、三環類抗抑鬱藥和選擇性血清素及正腎上腺素再 吸收抑制劑。當第一線藥物未能有效紓緩痛楚時，可考 慮轉換另一種第一線藥物或同時使用兩種一線藥物；而 曲馬朵 (tramadol) 可作為第二線治療選擇。link_to_OA_fulltex