[en] The relationship of the changes of hormone in patients with postpartum depressive disorder on 28-32 weeks of pregnancy, 1 week and 4 weeks postpartum was studied. Depress affection and anxious affections were measured in 200 postpartum women by self-rating depression scale and self-rating anxiety scale. Serum estradiol (E₂) and progesterone (P) levels in postpartum women were measured by RIA with control group. Results showed that the prevalence rate of depress affection was 11% and that of anxious affection was 14%. The serum levels of P on the 1 week postpartum, E₂ in antepartum were showed higher in the depressed group compared with control group. There was a significant difference in the changes of serum E₂ before and after delivery between the depressed group and control group (P<0.05). The results suggested that there was a difference in the hormone changes in E₂ and P levels in the patients with postpartum depression after delivery. (authors)

[en] The temperature dependence of the radiative recombination zone in InGaN/GaN multiple quantum well light-emitting diodes is investigated. >From the electroluminescence spectra measured at various temperatures, it is found that there are two peaks at about 400 and 460 nm, which can be assigned as Mg-related and quantum well transitions, respectively. The behavior of these two peaks with temperature is modeled by the two rate equation. Based on this model, we deduce the activation energy of Mg in GaN films to be about 126 meV, which is consistent with reported results obtained by other techniques. [copyright] 2001 American Institute of Physics

[en] Objective: To evaluate the clinical value of 18floro-deoxyglucose positron emission tomography-CT(¹⁸FDG PET-CT) in the diagnosis of lymph node metastasis from advanced esophageal carcinoma. Methods: A prospective study is performed here to assess whether ¹⁸FDG PET-CT can improve the diagnostic accuracy in lymph node metastasis for patients with advanced esophageal carcinoma. Thirty patients had undergone esophagectomy with extensive lymph node dissection. PET-CT findings were compared with that of CT with pathological finding as the final say. Results: All patients were operated successfully without peri-operative complications. The pathologies] examination confirmed metastasis in 22 patients and 49 out of 243 excised lymph nodes. In CT analysis, the sensitivity was 40.8%, specificity was 96.9%, with a diagnostic accuracy of 85.6%, The positive and negative predictive value was 76.9%, 86.4% respectively; PET-CT resulted in a sensitivity of 93.9%, specificity of 91.2%, accuracy of 91.8%. The positive predictive value was 73.0% and negative predictive value was 98.3 %, The difference of sensitivity (P<0.001 ), accuracy (P<0.05) and negative predictive value between the two radiological modalities was statistically significant (P<0.001). Conclusions: With a high sensitivity and accuracy in the diagnosis of lymph node metastasis, PET-CT appears necessary in preoperative examination for advanced esophageal carcinoma in the hope that surgical treatment be guided by the results of PET-CT, especially for the elder patients with poor pulmonary function or heart or brain complications. Moreover, it could be used as the basis of the conformal radiation therapy planning for inoperable patients. (authors)

[en] Objective: Under different standard uptake value(SUV), to assess gross tumor volume (GTV) definition for non-small cell lung cancer (NSCLC) with 18-fluoro-deoxy-glueose positron emission tomography(¹⁸FDG PET) both under definite threshold (42 percent threshold) and various relative threshold (threshold SUV/maximum SUV) derived from the linear regressive function, threshold SUV=0.307 x (mean target SUV) + 0.588, with computer tomography(CT). Methods: Of 20 patients with non-small cell lung cancer, the CT GTV (GTV_CT), PET GTV with 42 percents threshold (GTV_42%) and PET GTV with relative threshold (GTV_relate) were obtained and compared. Results: The mean GTV_42%, mean GTV_relate and mean GTV_CT was (13 812.5±13 841.4), (24 325.3±22 454.7) and (28350.9± 26 079.8) mm³, respectively, with the difference in mean GTV among these three methods significant (F =. 10, P<0.01). The GTV_42% was smaller than the GTV_relate and the GTV_CT (P<0.01), with insignificant difference between GTV_relate and GTV_CT (P = 0.125 ). Conclusion: The relative threshold is more suitable to define the gross tumor volume than the definite threshold. (authors)

[en] Objective: To evaluate the clinical value of 18-fluoro-deoxyglucose positron emission tomography-CT(¹⁸FDG PET-CT) for recurrence and metastasis in treated esophageal carcinoma(EC). Methods: A retrospective study is done on 37 previously treated EC patients who underwent PET-CT scans to detect recurrent or metastatic lesions. The diagnostic accuracy of ¹⁸FDG PET-CT was assessed with the help of pathological finding as well as clinical or' follow-up data. Results: Fourty-six sites of recurrence were finally confirmed in 37 patients by cytology, pathology or follow-up data. The sensitivity, specificity and accuracy of PET-CT in detecting recurrence of all sites were 93.5% (43/46), 76.9% (20/26) and 87.5% (63/72), respectively. Two false-positive findings were found both at the anastomosis and hilar nodes, which caused the decrease in the overall specificity, especially that locally. The analysis of standard uptake value (SUV) demonstrated that patients with recurrence or who died during follow-up had higher SU- Vs compared with the control group. Conclusions: ¹⁸FDG PET-CT is highly effective in detecting recurrence in previously treated EC patients despite the low specificity at local sites. The analysis of stardard uptake value(SUV) provides incremental value in prognosis for this patient cohart. (authors)

[en] Objective: To investigate the impact of PET/CT on clinical staging of non-small cell lung cancer (NSCLC), delineation of target volume, and prediction to alleviate radiation pneumonitis (RP) from 3-dimentional conformal radiotherapy (3D-CRT) planning. Methods: From October 2002 to June 2004, 34 patients diagnosed cytologically or pathologically with NSCLC, who were candidates for radical radiotherapy or surgery, received PET/CT scanning. Both images were transmitted into treatment planning system (TPS) workstations respectively and were fused and reconstructed. All patients were staged according to the 1997 World Health Organization (WHO) staging system. The impact of PET/CT on the clinical staging of all the patients was determined. The gross tumor volume (GTV) was delineated on the CT imaging and PET/CTfused imaging respectively. Based on the two images, 3D- CRT planning was made respectively at the TPS workstation with Topslane software, the planning target volumes (PTV) being defined with a 15 mm margin around GTV of primary lumps (PTV₁) and 7 mm for involved lymph nodes (PTV₂). Evaluating indexes including V_PTV (volume of PTV, V_PTV = V_PTV1 + V_PTV2), V₂₀ (percentage of the total lung volume receiving more than 20 Gy), MLD (mean lung dose) , TCP (tumor control probability) , NTCP (normal tissue complication probability) , and Ds (dose to spinal cord) were selected to be paralleled to compare the quality of the two plans and the impact of PET/CT on RP was further analyzed. Results: In 13 of 34 (38.2%) cases, PET/CT information changed the clinical staging, 8 of which were upstaged and 5 downstaged. For 10 of 34 (29.4%) cases, PET/CT results modified their management decisions. Among 16 patients performed by surgery, 14 had consistent PET/CT staging with pathologic staging. The sensitivity of PET/CT was 93.3% and accuracy 87.5%. Difference of indexes including V_PTV, V₂₀ and MLD between the two radiation planning was statistically significant, but Ds, TCP and NTCP were not statistically different. Conclusion: PET/CT has notable impact on clinical staging, target volume delineation and hence on its 3D-CRT planning of NSCLC. In contouring the target volume, compared with CT imaging, PET/CT can decrease V_PTV, V₂₀ and MLD significantly in patients with atelectasis and obstructive pneunonitis, so can reduce the rate and severity of RP effectively and can better protect normal lung tissues. (authors)

[en] Objective: To compare the difference of decreasing radiation-induce lung injure among CT scans including active breathing control (ABC), slow CT scan and general axial CT scan under free breathing (FB) in precise radiotherapy of peripheral non-small cell lung cancer (NSCLC). Methods: Ten patients of peripheral NSCLC were included. For each patient, three CT scans were obtained: (1) the general axial CT scans under FB; (2) the fast spiral CT scans under ABC; (3) the slow CT scans under FB. Three treatment plans based on three CT scans were optimized. Gross tumor volume (GTV), clinical target volume (CTV) and planning target volume (PTV) along with V₂₀ (lung volume accepted > 20 Gy/all lung volume x 100%) and D_mean (average dosage accepted irradiation of all lung )of three treatment plans were calculated and compared. Results: The GTV and CTV of the slow CT plan seem in largest, and those of ABC plan in smallest, but no statistics signification among the three plans (F=1.513, P=0.238; F=1.376, P=0.270). However, The PTV of the FB plan was largest, and the difference of PTV between plans of ABC and FB, plans of slow CT scans and FB were statistics significant (F=26.148, P=0.000). The differences of V₂₀20 and D_mean between plans of FB and ABC, plans of FB and slow CT scans were statistics significant yet (F=7.623, P=0.002; F= 18.217, P=0.000). Conclusion: Compared with FB conditions, ABC or the slow CT scan method in precise radiotherapy of peripheral NSCLC can decrease radiation volume and dose to normal tissues as well as the probability of decreasing radiation-induce hung injure. (authors)

[en] Objective: ¹⁸F-FDG PET/CT is now widely used in clinical staging of lung cancer. But false positive(FP) and negative (FN) results may occur. The aim of this study was to analyze the factors causing false ¹⁸F-FDG PET/CT results in the detection of lymph node in non-small cell lung cancer (NSCLC). Methods: Forty-eight patients underwent pulmonary lobectomy and dissection of lymph nodes after their ¹⁸F-FDG PET/CT and contrast enhanced CT results were retrospectively reviewed. The pathological status of the resected lymph nodes was the major concern. Results: The pathological examination confirmed metastasis in 51 out of 313 excised lymph nodes in 48 patients. There were 7 FN and 8 FP lymph nodes in PET/CT. The positive and negative predictive values of PET/CT were 85% and 97%, respectively, compared with 57% and 94% of CT(P=0.002, 0.045; respectively). Among the seven FN lymph nodes, 3 were with smaller tumor foci, 2 were 0.4 mm in short axis, and 2 proximate to the primaries were masked by the higher uptake of the primary tumor. The 8 FP lymph nodes were all with pulmonary complications and lymphadenitis. Conclusion: The smaller size, micro-metastases, and little separation from the primaries were the major reasons for FN, and the lymphadenitis with pulmonary complications for FP lymph node imaging in PET/CT. (authors)

[en] Objective: To evaluate the value of fluorodeoxyglucose (¹⁸FDG) PET-CT in detecting the micrometastatic mediastinal lymph node in non-small cell lung cancer (NSCLC). Methods: From April 2003 to October 2003, 12 consecutive patients with pathologically proven NSCLC were examined by¹⁸FDG PET-CT preoperatively to evaluate the mediastinal lymph nodes, of which the short diameter was less than 10 mm. The number and location of the metastatic mediastinal lymph-node was recorded. Postoperative pathology was taken as the 'gold standard' to confirm the image diagnosis of mediastinal lymph node. Results: Of 76 recorded < 10 mm lymph nodes 6 were positive and 70 negative by pathology. By PET-CT: 5 were positive, 67 negative, 3 false positive and 1 false negative. The sensitivity and specificity of ¹⁸FDG PET-CT were 83.3% and 95.7% with a diagnostic accuracy of 94.7%. The positive and negative predictive values of PET-CT were 62.5% and 98.6%. Conclusions: ¹⁸FDG PET-CT is reliable and accurate in detecting the micrometastatic mediastinal lymph-node. ¹⁸FDG PET-CT has great clinical value in guiding the management of NSCLC. (authors)

[en] Objective: It was realized that static PET imaging might not be accurate at fixed time point after ¹⁸F-FDG administration. The dual phase ¹⁸F-FDG PET was employed in this study in order to differentiate malignant from benign lesions. Methods: Fifty-two patients with difficulty in interpreting the nature of their lesions at routine imaging underwent delayed whole body ¹⁸F-FDG PET at 2 h post-injection. Visual inspection of PET images and SUV compared with pathological finding were used for evaluation. Resuits: Of 43 cases with increased SUV in delay imaging, 39 were confirmed malignant and 4 benign. And 7 of 9 cases with decreased SUV were confirmed benign and 2 malignant. The dual phase PET imaging in this group of patients had sensitivity of 95.1%, specificity 63.6%, accuracy 88.5%, positive predictive value 90.7%, and negative predictive value 7/9. Conclusion: In differentiating malignant from benign lesions, dual phase PET was more accurate than single static imaging. (authors)