Kai-Yuan Cheng

18F-FDG PET or PET/CT for detection of metastatic lymph nodes in patients with endometrial cancer: A systematic review and meta-analysis

UNLABELLED The present study assessed the diagnostic performances of 18F-FDG PET or PET/CT in detecting pelvic and/or paraaortic lymph node metastasis in patients with endometrial cancer. METHODS Through a search of MEDLINE (January 1998 to March 2011), an overall weighted average for sensitivity and specificity as well as pooled estimates of positive and negative likelihood ratios were calculated. A summary receiver-operating-characteristics (sROC) curve was constructed and the area under the sROC curve (AUC) was calculated. I-square was calculated to explore heterogeneity. RESULTS The present study included 243 patients from seven studies. Results indicated a lack of significant heterogeneity for sensitivity and specificity (I2<50% and p>0.05). The overall pooled estimates for sensitivity and specificity of FDG-PET or PET/CT scans in the detection of pelvic and/or paraaortic metastasis were 63.0% (95% CI, 48.7-75.7%) and 94.7% (95% CI, 90.4-97.4%), respectively. The positive likelihood ratio was 10.465 (95% CI, 5.646-19.396) and the negative likelihood ratio 0.399 (95% CI, 0.284-0.560). The AUC was 0.9533. The overall diagnostic accuracy (Q* index) was 89.5%. Conclusion The high positive likelihood value confirms the reliability of a positive FDG-PET or PET/CT to detect pelvic and/or paraaortic lymph nodes metastasis in patients with untreated endometrial cancer. FDG-PET or PET/CT may prove beneficial to surgeons when selecting appropriate patients on whom to perform lymphadenectomy.

Diagnostic value of bone and Ga-67 imaging in skeletal tuberculosis

Tuberculosis (TB) remains a major cause of skeletal infection in many parts of the world. Bone scintigraphy is an excellent screening test for bone lesions and Ga-67 scintigraphy is a useful tool for detecting inflammatory lesions. This study determined the value of bone and Ga-67 scans in patients with skeletal TB. Tc-99m MDP and Ga-67 whole-body scans were performed in 24 patients with proved skeletal TB. Twenty-six TB lesions were found in these 24 patients, 8 in the spine, 5 in the knee, 5 in the wrist, 4 in the ankle, 2 in the elbow, 1 in the finger, and 1 in the sacroiliac joint. Of the 26 TB lesions, Tc-99m MDP bone imaging detected 24 and Ga-67 scans revealed 23. The sensitivity rates were 92% (24 of 26) and 88.5% (23 of 26) for bone scans and Ga-67 scans, respectively. When the scans were evaluated in combination, the detection sensitivity was 96.1% (25 of 26). Two lesions that the bone scan failed to detect were in the spine. Ga-67 imaging failed to detect two spinal lesions and one lesion in the knee. The detection sensitivities of bone and gallium scans were high for skeletal TB, although neither scan was specific for TB lesions. Either the bone or Ga-67 scan can be used in the clinical setting as a convenient screening test to detect multiple sites of bone involvement in TB, and to indicate the sites for further detailed evaluation by CT, MRI, or biopsy.

Effect of pH on Fenton process using estimation of hydroxyl radical with salicylic acid as trapping reagent

This study estimates the yield of hydroxyl radical using salicylic acid as the trapping reagent and investigates the relationship between hydroxyl radical and pH value. The formation and variation of hydroxyl radical under different pH values were evaluated using reaction products, 2,3-DHBA, 2,5-DHBA, and catechol. The formation rate of hydroxyl radical was dependent on the ratio of ferrous ion to hydrogen peroxide and pH values. The difference between various pH values was explored. The kinetics and mechanisms of hydroxyl radical reactions were established in the Fenton process. Experimental results showed that the best reaction conditions were 8.5 mM H(2)O(2), 1.25 mM Fe(2 + ), Fe(2 + )/H(2)O(2) = 0.147 at pH 3 and the formation rate constant of hydroxyl radical was 1.12 x 10(11) M(-1) s(-1).

Fluorine-18 FDG-PET in detecting local recurrence and distant metastases in breast cancer: Taiwanese experiences

Fluorine-18 fluorodeonyglucose positron emission tomography (FDG-PET) was used to detect local recurrence, axillary lymph node (LN) involvement and distant metastases in patients with breast cancer. Thirty-six female patients with breast cancer s/p operation underwent FDG-PET studies. Findings were confirmed by histology following surgery and/or biopsy or negative follow-up results over a period of at least one year. In the evaluation of local recurrence, the diagnostic sensitivity, specificity, and accuracy of FDG-PET was 100, 96.8, and 97.2%, respectively. In the evaluation of axillary LN involvement, sensitivity, specificity, and accuracy was 80, 100, and 97.2%, respectively. In the evaluation of distant metastases, the diagnostic sensitivity, specificity, and accuracy was 83.3, 85.2, and 84.4%, respectively. The FDG-PET is a useful diagnostic tool in detecting local recurrence, axillary LN involvement, and distant metastasis.

Intra-tumoural injection of 90Y microspheres into an animal model of hepatoma.

Background Intrahepatic arterial injection of 90Y glass microspheres (90Y microspheres) is a useful therapeutic modality for inoperative liver tumour. Recently, a new concept of interstitial radiotherapy in the treatment of hepatic malignancies has been carried out with even more encouraging results. However, information regarding this technique is still very rare. The purpose of this study was to analyse the kinetics and biodistribution of 90Y microspheres in rats with hepatic tumours following intra-tumoural injection. Methods Twenty male Sprague-Dawley rats with hepatoma were killed at 1 h, 24 h, 48 h and 72 h (five rats each time) after intra-tumoural injection of approximately 7.4 MBq of 90Y microspheres. Samples of various organs were obtained and used to calculate the tissue concentrations and radiation doses. Results Our data showed that the radioactivity in the tumour was very high throughout this study. The lung was the only organ other than the tumour which showed high radioactivity. The concentrations of radioactivity in other organs, such as normal liver, muscle, spleen, bone, testis, and whole blood were quite low throughout the study. Conclusion Direct intra-tumoural injection of 90Y microspheres is extremely attractive as a clinical therapeutic alternative in hepatoma patients.

Accuracy of whole-body FDG-PET and FDG-PET/CT in M staging of nasopharyngeal carcinoma: A systematic review and meta-analysis

BACKGROUND A meta-analysis was conducted to evaluate the accuracy of whole-body positron emission tomography (PET) or PET/CT in M staging of nasopharyngeal carcinoma (NPC). METHODS Through a search of relevant English language studies from October 1996 to September 2011, pooled estimated sensitivity, specificity, positive likelihood ratios, negative likelihood ratios, and summary receiver operating characteristic (SROC) curves of whole-body PET or PET/CT in M staging of NPC were calculated. RESULTS Three PET and 5 PET/CT studies were identified. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of FDG-PET or PET/CT were 0.83 (95% confidence interval [CI], 0.77-0.88), 0.97 (95% CI, 0.95-0.98), 23.38 (95% CI, 16.22-33.69), and 0.19 (95% CI, 0.13-0.25), respectively. The area under curve was 0.9764 and Q* index estimate was 0.9307 for FDG-PET or PET/CT. CONCLUSION Current evidence confirms the good diagnostic performance of the whole-body FDG-PET or PET/CT in M staging of NPC.

PET or PET/CT for detection of peritoneal carcinomatosis: A meta-analysis

&NA; The present study assessed the diagnostic performances of 18F-FDG PET or PET/CT in detecting peritoneal carcinomatosis in patients with cancer. Methods Through a search of MEDLINE (January 1998 to September 2012), an overall weighted average for sensitivity and specificity was calculated using the weighted averages of the sample sizes in each relevant study. Pooled estimates of positive and negative likelihood ratios were calculated using fixed and random effects models, respectively, according to the heterogeneity among studies. A summary receiver operating characteristics (sROC) curve was constructed and the area under the sROC curve (AUC) was calculated. To explore heterogeneity, due to sources other than threshold effects, I-square was calculated. Results The present study included analyses of patients (n = 513) from 7 studies. Results indicated a significant heterogeneity for sensitivity and specificity (I2 > 50% and P < 0.05). The overall pooled estimates for sensitivity and specificity of FDG PET or PET/CT scans in the detection of peritoneal carcinomatosis were 72.4% (95% CI, 64.4%–79.5%) and 96.7% (95% CI, 94.4%–98.3%), respectively. The positive likelihood ratio was 10.414 (95% CI, 6.195–17.506) and the negative likelihood ratio 0.312 (95% CI, 0.159–0.612). The AUC was 0.9404. The overall diagnostic accuracy (Q* index) was 87.8%. Conclusion The high specificity may provide the reliability of a positive FDG PET or PET/CT to detect peritoneal carcinomatosis in patients with cancer. FDG PET or PET/CT has only weak power to exclude the presence of peritoneal carcinomatosis. By a good overall diagnostic accuracy, FDG PET or PET/CT may prove beneficial to surgeons when selecting appropriate patients on whom to perform laparoscopy or laparotomy.

Value of Gallium-67 Scintigraphy in Monitoring the Renal Activity in Lupus Nephritis

In this study, we evaluated the relationship between the gallium uptake in the kidneys and the results of renal biopsy. The renal uptake of gallium in 32 patients with lupus nephritis were evaluated according to the classification of the World Health Organization, the activity index (AI), and the chronicity index (CI). AI was significantly higher in patients with a positive gallium scan when compared with patients with a negative gallium scan (p = 0.0007). However, change in gallium uptake was not related to the CI or WHO classification (p = 0.68 and p = 0.79 respectively). Of the 16 patients with AI > or = 9, 13 (81.25%) had a positive gallium scan, while only 3 (18.7%) of the patients with AI < 9 had a positive scan. In addition, all patients (100%) with AI > or = 11 showed a positive gallium scan. We conclude that renal imaging with gallium has a good correlation with AI, and may be a useful alternative to renal biopsy in patients with lupus nephritis.

A Comprehensive Evaluation of NIPAM Polymer Gel Dosimeters on Three Orthogonal Planes and Temporal Stability Analysis.

Polymer gel dosimeters have been proven useful for dose evaluation in radiotherapy treatments. Previous studies have demonstrated that using a polymer gel dosimeter requires a 24 h reaction time to stabilize and further evaluate the measured dose distribution in two-dimensional dosimetry. In this study, the short-term stability within 24 h and feasibility of N-isopropylacrylamide (NIPAM) polymer gel dosimeters for use in three-dimensional dosimetry were evaluated using magnetic resonance imaging (MRI). NIPAM gels were used to measure the dose volume in a clinical case of intensity-modulated radiation therapy (IMRT). For dose readouts, MR images of irradiated NIPAM gel phantoms were acquired at 2, 5, 12, and 24 h after dose delivery. The mean standard errors of dose conversion from using dose calibration curves (DRC) were calculated. The measured dose volumes at the four time points were compared with those calculated using a treatment planning system (TPS). The mean standard errors of the dose conversion from using the DRCs were lower than 1 Gy. Mean pass rates of 2, 5, 12, and 24 h axial dose maps calculated using gamma evaluation with 3% dose difference and 3 mm distance-to-agreement criteria were 83.5% ± 0.9%, 85.9% ± 0.6%, 98.7% ± 0.3%, and 98.5% ± 0.9%, respectively. Compared with the dose volume histogram of the TPS, the absolute mean relative volume differences of the 2, 5, 12, and 24 h measured dose volumes were lower than 1% for the irradiated region with an absorbed dose higher than 2.8 Gy. It was concluded that a 12 h reaction time was sufficient to acquire accurate dose volume using the NIPAM gels with MR readouts.

A Novel Thin NIPAM Gel Cassette Dosimeter for Photon-Beam Radiotherapy

The response of thin polymer gel cassettes (called NIPAM gels) to ionizing radiation was investigated in this study. The NIPAM gels were prepared from gelatin, N-isopropyl acrylamide, tetrakis (hydroxymethyl) phosphoniumchloride, and N,N′-methylene-bis-acrylamide. Gel cassettes were irradiated in a phantom using a linear accelerator, and the polymerization morphology of irradiated NIPAM gel was characterized using scanning electron microscopy. The dose-response sensitivity of the NIPAM gels was evaluated using the differences in optical densities. The optical densities were obtained using a computer-controlled CCD camera that was connected to a planar illumination source for acquisition of optical transmission images. The central axis depth dose profiles of the phantom were extracted, and a comparison with ionization chamber measurements demonstrated similarities in profiles. The sensitivity, linearity of the response, accuracy, and reproducibility of the polymer gel cassettes were acceptable. However, the profiles of the half-blocked field irradiation showed no significant dispersion in the visible region. This study also extensively investigated the spatial stability of the NIPAM gel. The results showed that the gel cassette response remains stable for up to three months after irradiation.