[en] Malignant pleural mesothelioma (MPM) has a poor prognosis and a strong association with exposure to asbestos. Although there are not generally accepted guidelines for treatment of MPM, recent reports suggest that multimodality therapy combining chemotherapy, radiotherapy, and surgery can improve the survival of patients with MPM. Therefore exact staging is required to decide the best treatment option. However, it is well known that there are many difficulties in determining precise preoperative stage, predicting prognosis, and monitoring response to therapy with conventional imaging modalities such as CT and MRI in MPM. Recently PET with ¹⁸F-FDG comes into the spotlight as an important staging method. There is increasing evidence that PET is superior to other conventional imaging modalities in diagnosis and staging of MPM. Particularly PET/CT improves the diagnostic and staging accuracy over PET or CT alone in MPM because it provides anatomic imaging data as well as functional information. PET and PET/CT are also useful for monitoring response to therapy and SUV is reported as a prognostic factor in MPM

[en] Introduction: High-dose ¹⁸F-FDG can provide targeted nuclear therapy of cancer. Endothelial cell injury is a key determinant of tumor response to radiotherapy. Here, we tested the hypothesis that activation of endothelial cell glycolytic metabolism with nitric oxide can enhance the therapeutic effect of high-dose ¹⁸F-FDG. Methods: Calf pulmonary artery endothelial (CPAE) cells were treated with graded doses of ¹⁸F-FDG. Glycolysis was stimulated by 24 h of exposure to the nitric oxide donor, sodium nitroprusside (SNP). Cell viability was assessed by MTT and clonogenic assays. Apoptosis was evaluated by ELISA of cytosolic DNA fragments and Western blots of cleaved caspase-3. Results: SNP stimulation (0.1 and 1 mM) augmented CPAE cell ¹⁸F-FDG uptake to 2.6- and 4.6-fold of controls without adverse effects. Treatment with 333 μCi/ml ¹⁸F-FDG alone reduced viable cell number to 35.4% of controls by Day 3. Combining 0.1 mM SNP stimulation significantly enhanced the killing effect, reducing cell numbers to 19.2% and 39.2% of controls by 333 and 167 μCi/ml of ¹⁸F-FDG, respectively. ¹⁸F-FDG also suppressed clonogenic survival to 80.8% and 43.2% of controls by 83 and 167 μCi/ml, which was again intensified by SNP to 59.7% and 21.1% of controls. The cytotoxic effect of ¹⁸F-FDG was attributed to induction of apoptosis as shown by increased cytosolic fragmented DNA and cleaved caspase-3 levels (26.4% and 30.7% increases by 167 μCi/ml). Combining SNP stimulation significantly increased both of these levels to 1.8-fold of control cells. Conclusion: High-dose ¹⁸F-FDG combined with nitric oxide-stimulated glycolysis is an effective method to inhibit endothelial cell survival and promote apoptosis. These results suggest a potential role of this strategy for targeted radiotherapy of angiogenic vasculature.

[en] We investigated prospectively whether the interpretation considering the patterns of FDG uptake and the findings of unenhanced CT for attenuation correction can improve the diagnostic accuracy for assessing malignant lymph node (LN) and N stage in non-small cell lung cancer (NSCLC) using CT-corrected FDG-PET (PET/CT). Subjects were 91 NSCLC patients (M/F: 62/29, age: 60 ± 9 yr) who underwent PET/CT before LN dissection. We evaluated the maximum SUV (maxSUV), patterns of FDG uptake, short axis diameter, and calcification of LN showing abnormally increased FDG uptake. Then we investigated criteria improving the diagnostic accuracy and correlated results with postoperative pathology. In step 1, LN was classified as benign or malignant based on maxSUV only. In step 2, LN was regarded as benign if it had lower maxSUV than the cut-off value of step 1 or it had calcification irrespective of its maxSUV. In step 3, LN regarded as malignant in step 2 was classified as benign if they had indiscrete margin of FDG uptake. Among 432 LN group surgically resected (28 malignant, 404 benign), 71 showed abnormally increased FDG uptake. We determined the cut-off as maxSUV=3.5 using ROC curve analysis. The sensitivity, specificity, and accuracy for assessing malignant LN were 64.3%, 86.9%, 85.4% in step 1, 64.3%, 95.0%,93.1% in step 2, and 57.1%, 98.0%, 95.4% in step 3, respectively. The accuracy for assessing N stage was 64.8% in step 1, 80.2% in step 2, 85.7% in step 3. Imterpreting PET/CT, consideration of calcification and shape of the FDG uptake margin along with maxSUV can improve the diagnostic accuracy for assessing malignant involvement and N stage of hilar and mediastinal LNs in NSCLC

[en] This paper aims to address the cellular toxicity of ultra-pure titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles (NPs) frequently employed in sunscreens as inorganic physical sun blockers to provide protection against adverse effects of ultraviolet (UV) radiation including UVB (290-320 nm) and UVA (320-400 nm). In consideration that the production and the use of inorganic NPs have aroused many concerns and controversies regarding their safety and toxicity and that microsized TiO₂ and ZnO have been increasingly replaced by TiO₂ and ZnO NPs (< 100 nm), it is very important to directly investigate a main problem related to the intrinsic/inherent toxicity of these NPs and/or their incompatibility with biological objects. In the present study, we took advantage of the laser-assisted method called laser ablation for generation of TiO₂ and ZnO NPs. NPs were prepared through a physical process of irradiating solid targets in liquid phase, enabling verification of the toxicity of ultra-pure NPs with nascent surfaces free from any contamination. Our results show that TiO₂ NPs are essentially non-poisonous and ZnO NPs are more toxic than TiO₂ NPs based on the cell viability assays

[en] To find out the sonographic criteria which can be effectively used to differentiate acute appendicitis from non-appendicitis in patients with appendices with borderline diameter(5-8 mm). Sixteen patients diagnosed as acute appendicitis, another 16 patients diagnosed as non-appendicitis were included in this study. They complained of RLQ pain and their appendices measured 5-8 mm in diameter on sonogram. Features such as appendiceal wall thickness, presence or absence of air in appendiceal lumen, movability of tip of the appendix, compressibility of the appendix were evaluated on gray-scale sonogram and thereafter, presence or absence of color flow in the wall of the appendix was evaluated on color Doppler sonogram. Thickness of appendiceal wall is 2.98 ± 0.77 mm in acute appendicitis group and 1.73 ± 0.44 mm in non-appendicitis group (p<0.05). When 2.5 mm thickness of appendiceal wall is applied for diagnosis of acute appendicitis, sensitivity is 81.3%, specificity is 87.5% and accuracy is 84.4%. With absence of air in appendiceal lumen, sensitivity is 93.8%, specificity is 68.8% and accuracy is 81.3%. With absence of movability of appendiceal tip, sensitivity is 87.5%, specificity is 50% and accuracy is 68.8%. With absence of compressibility of the appendix, sensitivity is 100%, specificity is 31.3% and accuracy is 65.6%. With color flow in appendiceal wall, sensitivity is 81.3%, specificity is 62.5% and accuracy is 71.9%. The above mentioned criteria show statistically significant difference between acute appendicitis and non-appendicitis groups (p<0.05). When the diameter of the appendix measures 5-8 mm on sonogram, evaluation of thickness of appendiceal wall, air in appendiceal lumen, movability of tip, compressibility and color flow in the wall will be helpful to diagnose the acute appendicitis with confidence.

[en] Rare isotope beam facilities require shielding data in early stage of their design. There is much less shielding data on neutrons from the reactions between heavy ion beams and matter than the data on neutrons produced by protons. The purpose of the present work is to produce and thus increase the amount of shielding data on neutrons generated by high-energy heavy ion beams based on the RAON in-flight fragment facility. Calculations were performed with the computational Monte Carlo codes PHITS and MCNPX. The secondary neutron source terms were evaluated at 550 MeV/u for Ca, Kr, and Sn and at 400 MeV/u for U ions on a graphite target. Source terms and attenuation lengths were obtained by fitting the ambient dose equivalent inside an ordinary concrete shield

[en] We compared rest perfusion PET with redistribution perfusion SPECT to investigate the concordant rate between PET and SPECT images and analyze the discordant pattern. Rest N-13 ammonia and F-18 FDG PET were performed on 18 patients with old myocardial infarction and left ventricular dysfunction whose dipyridamole - 4hr redistribution TI-201 SPECT showed one or more severe fixed defects. Regional perfusion and metabolism were evaluated visually and quantitatively with 5-segment myocardial model. There were high concordant rate in uptake pattern (80/90 segments, 88.9%) and high correlation coefficient on quantitative analysis (R=0.81, p<0.001) between redistribution TI-201 SPECT and N-13 ammonia PET images. Nine of 18 patients had SPECT-PET concordant pattern (Group I). Ten segments (9 in inferior wall, 1 in apex) from the remaining 9 patients showed SPECT-PET discordant pattern with abnormal TI-201 defect and near normal N-13 ammonia uptake (Group II). The diastolic and systolic left ventricular dimensions were significantly increased in Group II compared to those of Group I. When attenuation uncorrected N-13 ammonia PET images were reconstructed in Group II, it resulted in PET images with severe inferior wall defects nearly identical to those seen in redistribution TI-201 SPECT images. Redistribution TI-201 SPECT images showed high concordant rate and correlation with rest N-13 ammonia PET images. Most of discordant segments had fixed thallium defects in inferior wall with nearly normal N-13 ammonia uptake, which may result from severe left ventricular dilatation and attenuation by the left hemidiaphragm and cardiac blood pool

[en] We investigated PET/CT diagnostic criteria for differentiating benign from malignant parotid lesions with focal ¹⁸F-FDG uptake. The subjects of the study were 272 patients who exhibited focal ¹⁸F-FDG uptake of the parotid gland. Sixty-eight pathologically confirmed parotid lesions from 67 patients were included. The maximum SUV (SUVmax), uptake patterns (homogeneous vs. heterogeneous), size measured by CT, maximum Housfield units (HUmax) and margins on CT (well vs. ill defined) of each parotid lesion on PET/CT images were compared with final diagnoses. Thirty- two parotid lesions were histologically proven to be malignant. There were significant differences in uptake patterns (cancer incidence, heterogeneous:homogeneous=79.2%:29.5%, p<0.0001) and margins on CT (cancer incidence, ill:well defined=84.4%:13.3%, p<0.0001) between benign and malignant lesions. The cancer risks of parotid lesions were 89.5% with heterogeneous uptake and ill-defined margins, 70.6% with heterogeneous uptake or ill-defined margins (no overlap in subjects) and 9.3% with homogeneous uptake and well-defined margins (p<0.0001). When any lesion with heterogeneous uptake or ill-defined margins was regarded as malignant, the sensitivity, positive predictive value, negative predictive value and accuracy were 90.6% (29/32) and 85.6% (58/68), respectively. For predicting malignancy, combined PET/CT criteria showed better sensitivity, NPV and accuracy than PET-only criteria, and had a tendency to have more accurate results than CT-only criteria, and had a tendency to have more accurate results than CT-only criteria. There were no significant differences in SUVmax, size or HUmax between benign and malignant lesions. Uptake patterns and margins on CT are useful PET/CT diagnostic criteria for differentiating benign from malignant lesions

[en] The extent and intensity of ^18F FDG uptake in prostate cancer patients are known to be variable, and the clinical significance of focal ^18F fluorodeoxyglucose (^18F FDG) uptake that is incidentally found on positron emission tomography (PET) has not been established. We investigated the clinical significance of incidental focal prostate uptake of ^18F FDG on PET/computed tomography (CT) and analyzed differential findings on PET/CT Between malignant and benign uptake. A total of 14,854 whole body ^18F FDG PET/CT scans (4,806 that were conducted during cancer screening and 10,048 that were conducted to evaluate suspected of alleged cancer outside of the prostate) were retrospectively reviewed to determine the presence, location, multiplicity reviewed to determine the presence, location, multiplicity and maximum standardized uptake value (SUVmax) of focal prostate uptake and combined calcification. The final diagnosis determined by serum prostate specific antigen (PSA) level and biopsy was compared with PET findings. Incidental focal prostate uptake was observed in 148 of 14,854 scans (1.0%). Sixty seven of these 148 subjects who had diagnostic confirmation were selected for further analysis. Prostate cancer was diagnosed in nine of 67 subjects (13.4%). The remaining 58 subjects had no malignancy in the prostate based on normal serum PSA level (n=53), or elevated serum PSA level with a negative biopsy result (n=5). While 84.6% (11/13) of malignant uptake was peripherally located in the prostate glands, 60.2% (50/83) of benign uptake was centrally located (p<0.05). The positive predictive value of peripheral focal uptake for malignancy was 25%. The SUVmax, multiplicity and combined calcification were not significantly different between the two groups. Although incidental focal ^18F FDG uptake un the prostate is not common, the incidence of cancer with focal uptake is not low. Therefore, these findings deserve further evaluation. The location of the focal prostate uptake may help with the selection of high risk prostate cancer patients.

[en] FDG PET is useful for detecting malignant solitary pulmonary nodules (SPNs). However, it can show false positive results in benign lesions such as tuberculosis and organizing pneumonia. We investigated whether FDG uptake pattern and morphological characteristics in CT for attenuation correction (CT-AC) of SPNs could improve accuracy for evaluating SPNs over SUV in integrated PET/CT using FDG. Forty patients (M:F = 23:17, mean age 58.2 yrs) with non-calcified SPNs (diameter on CT=30 mm, no significant mediastinal node enlargement, no atelectasis) were included. All subjects underwent integrated PET/CT. On PET images, peak SUV (pSUV) of SPN was acquired, and FDG uptake patterns were categorized as even or heterogeneous increase. SPNs were classified as benign or malignant according to their morphological characteristics such as margin shape and air bronchogram using CT-AC images regardless of PET finding. Thirty SPNs were confirmed as malignant, and 10 were benign by pathology. Of the 5 nodules with pSUV < 4.0, 4 nodules were benign. Nine of 14 nodules with pSUV between 4.0 and 7.0 were malignant, and 5 nodules were benign. Of the 21 nodules with pSUV of > 7.0, 20 nodules were malignant. When a nodule with evenly increased FDG uptake was considered as malignancy in indeterminate group with pSUV between 4.0 and 7.0, PET could diagnose 5 of 9 malignant nodules with one false positive nodule. In the remaining 8 nodules with heterogeneously increased FDG uptake, we could correctly differentiate malignancy from benignancy using CT-AC findings. Finally, this resulted in a sensitivity of 96.7% (29/30), specificity of 80% (8/10), and accuracy of 92.5% (37/40) to evaluate SPN. pSUV <4.0, 4.0-7.0 and >7.0 were suggestive of benign, indeterminate and malignant nodules, respectively. In indeterminate nodules, FDG uptake pattern and morphologic characteristics in CT-AC of SPN could improve the accuracy for evaluating SPNs in integrated PET/CT imaging