Comparing 18-fluoro-2-deoxyglucose positron emission tomography with a combination of technetium 99m tetrofosmin single photon emission computed tomography and computed tomography to detect recurrent or persistent nasopharyngeal carcinomas after radiotherapy

BACKGROUND

The diagnostic accuracy of combined computed tomography (CT) and technetium 99m tetrofosmin (Tc-TF) single photon emission computed tomography (SPECT) of head and neck to differentiate recurrent or residual nasopharyngeal carcinomas (NPCs) from benign lesions after radiotherapy was evaluated and compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG).

METHODS

Four months after radiotherapy, 36 patients with NPC underwent Tc-TF SPECT and CT of head and neck to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations were performed on nasopharyngeal biopsies of all 36 patients.

RESULTS

Based on the biopsy results, the sensitivity, specificity, and accuracy of Tc-TF SPECT were 64%, 96%, and 86%, respectively, for differentiation of recurrent or persistent NPC from benign lesions. For CT and FDG-PET, the sensitivity, specificity, and accuracy were 73%, 88%, and 83% and 100%, 96%, 97%, respectively. For the 27 patients with NPC whose Tc-TF SPECT and CT results were congruent, the combination of Tc-TF SPECT and CT had the same sensitivity, specificity, and accuracy (100%, 96%, and 96%) as FDG-PET. For the nine patients with NPC with incongruent Tc-TF SPECT and CT results, FDG-PET correctly differentiated two benign lesions from seven recurrent/residual NPCs.

CONCLUSIONS

Although, FDG-PET is the best tool for detecting recurrent or residual NPC, combined congruent Tc-TF SPECT and CT results achieved the same accuracy as FDG-PET. Therefore, we concluded that FDG-PET could be considered only when Tc-TF SPECT and CT give incongruent results.

Coexpression of Mutant p53 and p193 Renders Embryonic Stem Cell–Derived Cardiomyocytes Responsive to the Growth-Promoting Activities of Adenoviral E1A

Abstract —Expression of adenoviral E1A in cardiomyocytes results in the activation of DNA synthesis followed by apoptosis. In contrast, expression of simian virus 40 large T antigen induces sustained cardiomyocyte proliferation. Previous studies have shown that T antigen binds to 2 proapoptotic proteins in cardiomyocytes, namely the p53 tumor suppressor and p193 (a new member of the BH3-only proapoptosis subfamily). Structure-function analyses identified a p193 C-terminal truncation mutant that encodes prosurvival activity. This mutant was used to test the role of p193 in E1A-induced cardiomyocyte apoptosis. E1A induced apoptosis in cardiomyocytes derived from differentiating embryonic stem cells. Expression of the prosurvival p193 mutant alone or a mutant p53 alone did not block E1A-induced apoptosis. In contrast, combinatorial expression of mutant p193 and mutant p53 blocked E1A-induced apoptosis, resulting in a proliferative response indistinguishable from that seen with T antigen. These results confirm the hypothesis that there are 2 proapoptotic pathways, encoded by p53 and p193, respectively, which restrict cardiomyocyte cell cycle activity in differentiating embryonic stem cell cultures. Furthermore, these results explain in molecular terms the phenotypic differences of E1A versus T-antigen gene transfer in cardiomyocytes.

Comparison of technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and computed tomography to detect recurrent or residual nasopharyngeal carcinomas after radiotherapy

The diagnostic accuracy of technetium-99m methoxyisobutylisonitrile (Tc-MIBI) single photon emission computed tomography (SPECT) of head and neck to differentiate between recurrent or residual nasopharyngeal carcinomas (NPC) and benign lesions after radiotherapy was evaluated, and compared with computed tomography (CT). Thirty-six NPC patients 4 months after radiotherapy underwent Tc-MIBI SPECT and CT of head and neck, as well as histopathological examination of nasopharyngeal biopsies. Based on the biopsy results, the sensitivity, specificity, and accuracy of CT were 73%, 88%, and 83%, respectively. The sensitivity, specificity, and accuracy of Tc-MIBI SPECT were 64%, 96%, and 86%, respectively. The sensitivity, specificity, and accuracy of combined Tc-MIBI SPECT and CT were 100%, 88%, and 92%, respectively. Tc-MIBI SPECT had a better specificity and a lower sensitivity to differentiate benign lesions from recurrent/residual NPC when compared with CT The combined use of CT and Tc-MIBI SPECT significantly increased accuracy compared with the single use of either Tc-MIBI SPECT or CT to differentiate benign lesions recurrent/residual NPC.

Technetium-99m-sestamethoxyisobutylisonitrile scan as a predictor of chemotherapy response in malignant lymphomas compared with P-glycoprotein expression, multidrug resistance-related protein expression and other prognosis factors

The purpose of the present study was to predict the response of malignant lymphomas (MLs) to chemotherapy using technetium-99m methoxyisobutylisonitrile (Tc-MIBI) scan and to compare it with the predictive ability of P-glycoprotein (P-gp) expression, multidrug resistance-related protein (MRP) expression and other prognosis factors. Twenty-five ML patients were enrolled in this study prior to initiation of chemotherapy. Images were obtained 10 min after intravenous injection of Tc-MIBI, interpreted visually and the tumour-to-background (T/B) ratios calculated. Immunohistochemical analyses were performed on sections of the biopsy specimens to determine P-gp and MRP expression. Chemotherapy response was evaluated in the first 1-2 years after completion of chemotherapy. The mean T/B ratio of the 15 patients with a good response (3.3 +/- 0.6) was significantly higher than that of the 10 patients with a poor response (1.2 +/- 0.1). All 15 patients with a good chemotherapy response had positive Tc-MIBI scan results and negative P-gp and MRP expression. All 10 patients with a poor response had negative Tc-MIBI scan results and either positive P-gp or MRP expression. Other prognosis factors showed no significant difference in the incidence of good and poor responses. Tc-MIBI scan results represent P-gp or MRP expression more accurately than other prognosis factors and predict the chemotherapy response in ML patients.

Evaluation of hepatobiliary function by hepatobiliary scintigraphy in hepatoma patients after transcatheter arterial embolization

BACKGROUND

Transcatheter arterial embolization (TAE) is the treatment of choice for inoperable hepatocellular carcinoma. However, altered and impaired gallbladder function due to gallbladder infarction and bile duct necrosis following TAE have been reported.

METHODS

Hepatobiliary function was evaluated using quantitative Tc-99m DISIDA hepatobiliary scintigraphy in 40 hepatoma patients before and after TAE. The patients were separated into two groups: group 1 (20 patients), who received pre-cystic artery TAE, and group 2 (also 20 patients), who received post-cystic artery TAE.

RESULTS

After TAE, there were no significant changes in liver or bile duct function in the patients of either group. However, for group I patients, significantly decreased gallbladder function was found after TAE.

CONCLUSIONS

Altered and impaired gallbladder function is common in hepatoma patients who receive pre-cystic artery TAE, and Tc-99m DISIDA cholescintigraphy may be useful for evaluating hepatobiliary function in hepatoma patients who receive TAE.

RBP1 recruits the mSIN3-histone deacetylase complex to the pocket of retinoblastoma tumor suppressor family proteins found in limited discrete regions of the nucleus at growth arrest

Retinoblastoma (RB) tumor suppressor family pocket proteins induce cell cycle arrest by repressing transcription of E2F-regulated genes through both histone deacetylase (HDAC)-dependent and -independent mechanisms. In this study we have identified a stable complex that accounts for the recruitment of both repression activities to the pocket. One component of this complex is RBP1, a known pocket-binding protein that exhibits both HDAC-dependent and -independent repression functions. RB family proteins were shown to associate via the pocket with previously identified mSIN3-SAP30-HDAC complexes containing exclusively class I HDACs. Such enzymes do not interact directly with RB family proteins but rather utilize RBP1 to target the pocket. This mechanism was shown to account for the majority of RB-associated HDAC activity. We also show that in quiescent normal human cells this entire RBP1-mSIN3-SAP30-HDAC complex colocalizes with both RB family members and E2F4 in a limited number of discrete regions of the nucleus that in other studies have been shown to represent the initial origins of DNA replication following growth stimulation. These results suggest that RB family members, at least in part, drive exit from the cell cycle by recruitment of this HDAC complex via RBP1 to repress transcription from E2F-dependent promoters and possibly to alter chromatin structure at DNA origins.

Cerebral perfusion in patients with syndrome X: a single photon emission computed tomography study

OBJECTIVE

To test the hypothesis that syndrome X is a systemic vascular disorder, the authors studied 40 patients with this diagnosis using technetium-99m hexamethylpropylene amine oxime and single photon emission computed tomography (SPECT) brain images. Twenty-three of 25 cases with definite myocardial perfusion defects diagnosed by thallium-201 myocardial perfusion SPECT also had multiple hypoperfusion areas in the brain versus 2 of 15 patients without thallium myocardial defects. The parietal lobes were the most common hypoperfusion areas, and cerebellum was the least common. Syndrome X is a systemic vascular disorder with a high incidence of hypoperfusion lesions of the brain and is usually coincident with myocardial defects.

The simulation effects of mountain climbing training on selected endocrine responses

The simulation effects of mountain climbing exercise training on plasma testosterone, cortisol and luteinizing hormone (LH) levels were examined in ten recreational mountain male climbers. Subjects underwent a simulating mountain climbing exercise training 3 times a week for a total of eight weeks before an expedition to Mount Muztag Ata (7546 m, Xingian, China). During training, each subject carried a 40 kg back pack while walking on a treadmill at a speed of 1.9 mph for 60 min at sea level. Subjects completed an incremental treadmill test to exhaustion prior to training, after training, and one week after returning from Mount Muztag Ata. Blood samples were collected from antecubital vein at rest and at 5, 60, and 120 min post testing to determine the plasma testosterone, cortisol and LH levels. The basal plasma testosterone and cortisol concentrations were lower in both post-training and after-climbing conditions compared with that in the pre-training condition (p<0.01). The basal plasma LH concentration was remained unchanged after training and after the mountain climbing compared with levels measured in the pre-training phase. No correlation could be established between plasma LH and testosterone level. These results suggest that an eight-week period of mountain climbing training protocol may be beneficial in maintaining normal endocrine function during and after high altitude mountain expedition. Our results also indicate the decrease of plasma testosterone was LH independent.

Uptake of gallium-67 citrate in clean surgical incisions after colorectal surgery

Non-specific accumulation of gallium-67 citrate (gallium) in uncomplicated surgical incisions is not uncommon. It is important to know the normal pattern of gallium uptake at surgical incision sites in order to properly interpret the gallium scan when investigating possible wound infection in patients who have undergone abdominal surgery. We studied 42 patients without wound infection after colorectal surgery and performed gallium scans within 40 days after surgery. Patients were divided into three groups according to the interval between the operation and the scan. In group A (26 patients) gallium scan was performed within 7 days after surgery, in group B (8 patients) between 8 and 14 days after surgery, and in group C (8 patients) between 15 and 40 days after surgery. Our data showed that in group A, 61.5% had gallium accumulation at the surgical incision site. In group B, 50% had accumulation of gallium at the surgical incision site, while in group C only one patient (12.5%) showed gallium uptake. It is concluded that the incidence of increased gallium uptake at clean surgical incision sites is high after colorectal surgery. Nuclear medicine physicians should bear in mind the high incidence of non-specific gallium uptake at such sites during the interpretation of possible wound infection in patients after colorectal surgery.

Whole body 18F-2-deoxyglucose positron emission tomography to restage non-small cell lung cancer

The helpfulness of 18F-2-deoxyglucose positron emission tomography (FDG-PET) in restaging non-small cell lung cancer (NSCLC) has not been extensively evaluated. A total of 156 patients referred for restaging of NSCLC were retrospectively evaluated. According to the classification of American Joint Committee on Cancer, stages I and II were defined as conventionally resectable, stage IIIA as locally advanced but resectable, stage IIIB as locally advanced but unresectable, and stage IV as absolutely unresectable. Compared to initial staging by chest computed tomographic findings, FDG-PET down-staged 45/156 (29%) and up-staged 52/156 (33%) NSCLCs. In addition, 37/156 (23%) patients were reclassified from resectable to unresectable and 22/156 (14%) patients were reclassified from unresectable to resectable. Our results prove the helpfulness of whole body FDG-PET for restaging NSCLC.

Value of 18F-fluoro-2-deoxyglucose positron emission tomography in the evaluation of recurrent colorectal cancer

To evaluate the clinical value of positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) in recurrent colorectal cancer, the records of 33 patients who underwent 34 FDG-PET scans were reviewed and compared with computed tomography (CT) and carcinoembryonic antigen (CEA). The final diagnosis was based on operative, histopathological findings or clinical follow-up > 1 year. FDG-PET detected all 15 patients with recurrent diseases (9 local recurrences, 4 lymphatic metastases, 2 hepatic metastases and 8 pulmonary metastases) and 1 primary lung cancer. However, there were 3 false positive cases. The overall sensitivity and specificity of FDG-PET were 100% and 83%, respectively. The sensitivity and specificity of CEA were 33% and 86%, respectively, for detecting recurrent colorectal cancer. Abdominal CT had a sensitivity and specificity of 78% and 61% for detecting local recurrence and detected one lymphatic and one hepatic metastasis. In conclusion, the FDG-PET was more accurate than CT and CEA for the detection of recurrent colorectal cancer. In addition, it accurately detected distant metastases or occult secondary malignancy and may affect clinical management.

Technetium-99m tetrofosmin scintigraphy for detecting malignant lymphoma

The aim of this study was to assess the use of Tc-99m tetrofosmin (Tc-TF) scintigraphy for detecting malignant lymphomas. In the study, before any chemotherapy, 50 patients with malignant lymphoma underwent Tc-TF scintigraphy, which was performed 10 minutes after intravenous injection of 20 mCt Tc-TF. Tc-TF scintigraphy detected malignant lymphoma in 44 (88%) patients. However, there were no significant differences in the incidences of positive and negative Tc-TF scintigraphic results between female versus male patients, HD versus NHL patients, stage I-II versus stage III-IV patients, age > 40 years versus < or = 40 years patients and patients with B symptoms false-negative results occurred in 4 (8%) infradiaphragmatic malignant lymphoma. We conclude patients with that Tc-TF scintigraphy appears suitable for detecting malignant lymphoma, especially supradiaphragmatic lesions.

Effect of imaging time on gallium renal scan

AIM

Gallium renal imaging has been reported to be useful in monitoring disease activity and predicting the response to therapy in lupus nephritis. Gallium renal images are usually obtained 48 h after the injection of 67Ga citrate, but 72-h images sometimes are the only available pictures. The aim of the present study was to determine whether the time intervals from injection to imaging had any effect on the grading of gallium renal scintigraphy.

METHODS

Fifty-five patients with lupus nephritis underwent gallium renal imaging at both 48 h and 72 h post-injection of 111 MBq of 67Ga citrate. The relative uptakes of 67Ga by the kidneys and the spine was judged visually on the analog images. Renal uptake was rated on a scale of 0-3.

RESULTS

Fifty-three patients (96.3%) had the same grading of renal uptake in the 48-h and the 72-h images. Only two patients (3.7%) had a different grading in the 72-h images when compared to the 48-h images. The correlation between the 48-h renal uptake and 72-h renal uptake was excellent, with a Spearman R value of 0.94. No significant difference was noted between these two groups, with a P value of 0.76 (using a Wilcoxon matched pairs test).

CONCLUSION

A gallium renal scan can be obtained either 48 h or 72 h after injecting 67Ga citrate. The imaging time did not interfere with the grading of renal uptake in lupus nephritis.

Detection of cervical lymph node metastases in nasopharyngeal carcinomas: comparison between technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and computed tomography

The aim of this study was to compare the effectiveness of technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) and computed tomography (CT) of head and neck in evaluating cervical lymph node (LN) metastasis in nasopharyngeal carcinomas (NPC). Fifty NPC patients with suspected cervical LN metastases underwent Tc-99m MIBI SPECT and CT of the head and neck to evaluate cervical LN metastases. Among the 50 patient.s cervical LN lesion were confirmed by biopsy histopathological results in 40 patients. For 22 LN lesions with discordant results between Tc-99m MIBI SPECT and CT Tc-99m MIBI SPECT could correctly detect 5 metastatic and 7 benign LN lesions, while could correctly detect 5 metastatic and 6 benign LN lesions. Tc-99m MIBI SPECT and CT could correctly detect all of the 18 metastatic LN lesions. Tc-99m MIBI SPECT showed a better specificity but a lower sensitivity for detecting cervical LN metastases in NPC when compared with CT. The combined use of Tc-99m MIBI SPECT and CT could increase the accuracy, compared with the single use of either Tc-99m MIBI SPECT or CT, to detect cervical LN metastases in NPC.

Evidence of gallbladder function changes in hepatoma after transcatheter arterial embolization by quantitative Tc-99m DISIDA cholescintigraphy

BACKGROUND/AIMS

Transcatheter arterial embolization is the treatment of choice for inoperable hepatocellular carcinoma. Gallbladder infarction following transcatheter arterial embolization has been reported, therefore, the gallbladder functions were studied using the quantitative Tc-99m DISIDA cholescintigraphy in the present study.

METHODOLOGY

The gallbladder functions which were presented as the filling fraction and the ejection fraction in 24 patients with hepatoma before and after transcatheter arterial embolization. The patients were separated into two groups. Group 1: 12 patients received precystic artery transcatheter arterial embolization and group 2: 12 patients received postcystic artery transcatheter arterial embolization.

RESULTS

After transcatheter arterial embolization, significantly decreased both gallbladder functions of filling fraction (61.2 +/- 7.4% and 48.3 +/- 6.5%) and ejection fraction (47.8 +/- 6.0% and 36.5 +/- 5.3%) were found in group 1 patients. However, no significant change of filling fraction (59.0 +/- 5.0% and 58.8 +/- 7.4%) and ejection fraction (49.9 +/- 2.4% and 49.3 +/- 5.7%) in group 2 patients.

CONCLUSIONS

Impaired gallbladder functions were common in hepatoma patients who received precystic artery transcatheter arterial embolization, and Tc-99m DISIDA cholescintigraphy may be useful for evaluating the gallbladder functions in hepatoma patients who received transcatheter arterial embolization.

P-Glycoprotein and multidrug resistance-related protein expressions in relation to technetium-99m methoxyisobutylisonitrile scintimammography findings

The purpose of this study was to retrospectively study 48 patients with infiltrating ductal breast cancer to evaluate the relationship between the degree of accumulation of technetium-99m methoxyisobutylisonitrile (Tc-MIBI) and P-glycoprotein (Pgp) or multidrug resistance-related protein (MRP) expression in breast cancer tissues. Before surgery or biopsy, all 48 patients underwent scintimammography started 10 min after the injection of Tc-MIBI. Tumor:background (T:B) ratios were calculated from the Tc-MIBI scintimammography. Immunohistochemical analysis was performed on the pathological specimens of the 48 breast tumors to determine Pgp and MRP expression. According to the results of immunohistochemical analysis, the 48 breast cancers were separated into four groups: (a) group 1, 12 cancers with both positive Pgp expression and positive MRP expression; (b) group 2, 12 cancers with positive Pgp expression and negative MRP expression; (c) group 3, 12 cancers with negative Pgp expression and positive MRP expression; and (d) group 4, 12 cancers with both negative Pgp expression and negative MRP expression. Among the four groups, the T:B ratio was lowest in group 1 (1.13+/-0.10) and highest in group 4 (2.17+/-0.14), respectively (P < 0.05). The T:B ratios of groups 2 (1.30+/-0.25) and 3 (1.32+/-0.26) were between those of groups 1 and 4. Our data confirmed that Tc-MIBI scintimammography is useful for determining Pgp and MRP expression in patients with breast cancers.

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.

Sorption and diffusion behavior of Cs and Sr on Jih-Hsing bentonite

Sorption and diffusion are important processes for the transport of radionuclides through buffer materials such as bentonite. In this study, the sorption and diffusion behaviors of Cs and Sr on Jih-Hsing bentonite are investigated using batch and through-diffusion techniques. The distribution coefficients (Kds) of Cs and Sr from batch experiments are approximately 1200 ml/g and 800 ml/g, respectively. It is found that the Freundlich isotherm model could fit the sorption isotherm with an equilibrium concentration of 10(-7)-10(-1) N. The calculated retardation factors (Rds) for samples at densities of 1.8 g/cm3, 2.0 g/cm3 and 2.2 g/cm3 are 5685, 7744, and 11000 for Cs, and are 3790, 5162, and 7334 for Sr. For the through-diffusion experiments on the compacted samples with the same densities, the corresponding apparent diffusion coefficients for Cs are (2.83+/-0.75) x 10(-13) m2/s, (1.97+/-0.02) x 10(-13) m2/s, and (1.91+/-0.12) x 10(-13) m2/s, respectively. The corresponding apparent diffusion coefficients for Sr are (1.33+/-0.13) x 10(-13) m2/s, (1.51+/-0.15) x 10(-13) m2/s, and (1.34+/-0.10) x 10(-13) m2/s. The Rds obtained from the diffusion experiments for sample densities of 1.8 g/cm3, 2.0 g/cm3 and 2.2 g/cm3 are 1166+/-355, 2113+/-123, 2796+/-171 for Cs, and 713+/-258, 510+/-68, 846+/-158 for Sr. It appears that the retardation factors obtained from the diffusion experiments are about one order of magnitude lower than those derived from the batch experiments. The discrepancy and the possible explanations are discussed in the paper.