<Superscript>99m</Superscript>Tc-tetrofosmin or <Superscript>99m</Superscript>Tc-sestamibi for double-phase parathyroid scintigraphy?

Several years ago technetium-99m tetrofosmin was reported to localise parathyroid adenomas. The aim of this study was to compare the sensitivity of this radiopharmaceutical with that of (99m)Tc-sestamibi using a double-phase parathyroid scintigraphy protocol. Scans of 12 patients were evaluated visually and lesion to thyroid ratios were calculated. Nine of the patients were subsequently operated on; a total of eight parathyroid adenomas or hyperplastic glands were histologically confirmed in seven of the patients, while in one patient a parathyroid carcinoma was histologically proven. All of these patients had positive (99m)Tc-sestamibi scintigrams, whereas only two (99m)Tc-tetrofosmin scintigrams were positive. With (99m)Tc-sestamibi there was a significant increase in the lesion to thyroid ratio from 10 min to 90 min and 150 min p.i. which was not seen on scintigraphy with (99m)Tc-tetrofosmin. This makes (99m)Tc-tetrofosmin less suitable for double-phase parathyroid scintigraphy.     

In vivo imaging of tumour angiogenesis in mice with the α<Subscript>v</Subscript>β<Subscript>3</Subscript> integrin-targeted tracer <Superscript>99m</Superscript>Tc-RAFT-RGD

Purpose The molecular imaging of tumour neoangiogenesis currently represents a major field of research for the diagnostic and treatment strategy of solid tumours. Endothelial cells from tumour neovessels overexpress the α_vβ₃ integrin, which selectively binds to Arg-Gly-Asp (RGD)-containing peptides. We evaluated the potential of the novel radiotracer ^99mTc-RAFT-RGD for the non-invasive molecular imaging of α_vβ₃ integrin expression in mice models of tumour development. Methods ^99mTc-RAFT-RGD, ^99mTc-cRGD (specific control) and ^99mTc-RAFT-RAD (non-specific control) were injected intravenously to mice bearing B16F0 or TS/A-pc tumours. In vivo whole-body tomographic imaging and post-mortem biodistribution studies were performed 60 min following tracer injection. Adjacent tumour slices were used to compare the localisation of neovessels from immunostaining and the pattern of ^99mTc-RAFT-RGD uptake from autoradiographic ex vivo imaging. Results Biodistribution studies indicated that ^99mTc-RAFT-RGD tumour uptake was significantly higher than that of ^99mTc-RAFT-RAD in B16F0 (2.4±0.5 vs 1.0±0.1%ID/g, respectively) and in TS/A-pc tumours (2.7±0.8 vs 0.7±0.1%ID/g, respectively). Immunohistochemical and autoradiographic studies indicated that ^99mTc-RAFT-RGD intratumoural uptake preferentially occurred in angiogenic areas. Tomographic imaging allowed tumour visualisation following injection of ^99mTc-RAFT-RGD and ^99mTc-cRGD with similar tumour-to-contralateral muscle (T/CM) ratios in B16F0 and in TS/A-pc tumours whereas ^99mTc-RAFT-RAD T/CM ratios did not allow tumour imaging. In accordance with the higher level of α_vβ₃ integrin expression on TS/A-pc tumours than on B16F0 tumours as determined from western blot and immunoprecipitation analyses, the ^99mTc-RAFT-RGD T/CM ratio was significantly higher in TS/A-pc than in B16F0 tumours. Conclusion ^99mTc-RAFT-RGD allowed the in vivo imaging of α_vβ₃ integrin tumour expression.     

Myocardial kinetics of <Superscript>201</Superscript>Thallium, <Superscript>99m</Superscript>Tc-tetrofosmin,and <Superscript>99m</Superscript>Tc-sestamibi in an acute ischemia–reperfusion model using isolated rat heart

Objective ²⁰¹Thallium (TL), ^99mTc-tetrofosmin (TF), and ^99mTc-sestamibi (MIBI) are extensively used as myocardial perfusion agents. The objective of the present study was to evaluate their kinetics under acute ischemia–reperfusion. Methods Isolated rat hearts, perfused by the Langendorff method at a constant flow rate of 10 ml/min, were allotted to normal control, mild ischemia, and severe ischemia groups, in which 20-min tracer wash-in was conducted followed by a 25-min tracer washout. No-flow ischemia (15 min for mild ischemia groups; 30 min for severe ischemia groups) was induced before conducting wash-in and washout in the ischemia groups. Whole-heart radioactivity was determined with an external gamma detector. Myocardial flow rate (K ₁, ml/min) and clearance rate (k ₂, min⁻¹) were calculated. Results K _1TL, K _1TF, and K _1MIBI decreased according to the severity of ischemia (K _1TL 5.32 ± 0.53, 4.76 ± 0.70, and 1.44 ± 0.59; K _1TF 3.80 ± 0.70, 2.73 ± 0.99, and 1.09 ± 0.45; and K _1MIBI 3.45 ± 1.10, 2.15 ± 0.82, and 1.05 ± 0.13, in the normal control, mild, and severe ischemia groups, respectively). K ₁ was significantly higher for TL than for the ^99mTc tracers (P < 0.05), but the ^99mTc tracers had equivalent K ₁ values. k _2TL increased significantly (P < 0.05) in the ischemia groups (k _2TL 0.062 ± 0.013, 0.11 ± 0.045, and 0.12 ± 0.035), but showed no significant difference between the ischemia groups. k _2MIBI and k _2TF were significantly (P < 0.05) lower than k _2TL and increased significantly (P < 0.05) in the severe ischemia group (k _2TF 0.0056 ± 0.0022, 0.0037 ± 0.0015, and 0.024 ± 0.015; and k _2MIBI 0.00072 ± 0.0011, 0.00038 ± 0.00076, and 0.042 ± 0.034). k _2MIBI was significantly (P < 0.05) lower than k _2TF in the normal control and mild ischemia groups. Conclusions Tracer extraction was higher for TL than for the ^99mTc tracers and all tracers decreased according to the severity of ischemia–reperfusion in the three tracer groups. The clearance kinetics of not only MIBI but also TF is possibly useful for the evaluation of the severity of ischemia, and the Langendorff method and a methodological approach by continuous determinations of radioactivity may serve for the quantitative analysis of tracer kinetic profiles.     

Usefulness of brain <Superscript>99m</Superscript>Tc-TRODAT-1 SPET for the evaluation of Parkinson’s disease

Nigral dopaminergic projections to the striatum are targeted in Parkinsons disease (PD). The extent of the degeneration of the dopaminergic system in PD can be visualised by dopamine transporter imaging using single-photon emission tomography (SPET). In this study in 188 patients with PD, we analysed the image patterns and compared them with the clinical features in order to verify the usefulness of technetium-99m TRODAT-1 brain SPET in the evaluation of patients with PD. Two independent readers visually assessed SPET slices from three brain axes according to a fine visual scale; results were also grouped according to a rough visual scale. Results of both visual and semi-quantitative analyses were compared among patients with different stages of PD and healthy controls. There was good agreement between the readers in the interpretation of the image patterns [kappa statistic ()=0.85 for the presence of PD; =0.88 for the rough scale and 0.81 for the fine scale]. Good concordance was obtained when visual interpretation was used to evaluate the presence of PD (sensitivity =98%, specificity =86%, =0.85). Semi-quantitative analyses revealed significant negative correlations between both striatal and putaminal uptake and disease severity as assessed using the Hoehn and Yahr scale (=–0.89 and –0.93 respectively). An apparent decrease in striatal uptake in early PD, hardly discernible from the uptake level in advanced PD, was commonly found in visual analyses. The results suggest that both visual and semi-quantitative analyses of ^99mTc-TRODAT-1 SPET images reflect neurodegeneration in PD, and that ^99mTc-TRODAT-1 SPET represents an adequate means for evaluation of the status of patients with PD.     

Do androgens control the uptake of <Superscript>18</Superscript>F-FDG, <Superscript>11</Superscript>C-choline and <Superscript>11</Superscript>C-acetate in human prostate cancer cell lines?

Purpose  

The aim of this study was to evaluate the impact of androgen ablation therapy in different prostate cancer (PCa) cell lines—reflecting different stages of the disease—on ¹⁸F-fluorodeoxyglucose (FDG), ¹¹C-choline and ¹¹C-acetate uptake.     

The clinical utility of 99<Superscript>m</Superscript>Tc-HMPAO SPECT in Fahr’s disease

Fahr's disease is a rare neurodegenerative syndrome, characterized by massive symmetrical intracerebral calcifications of the basal ganglia, dentate nuclei of the cerebellum, and the adjacent parenchyma. Computerized tomography (CT) is considerably more sensitive to detect these intracranial calcifications than other imaging modalities. The clinical, CT scan, and 99(m)Tc-D,L-hexamethylpropylene amine oxime (99(m)Tc-HMPAO) brain perfusion single-photon emission computerized tomography (SPECT) findings in a 42-year-old woman with Fahr's disease are reported, and the clinical utility of 99(m)Tc-HMPAO SPECT findings in Fahr's disease is discussed in this article. In conclusion, 99(m)Tc-HMPAO brain perfusion SPECT seems to be useful in the clinical approach to Fahr's disease, and may provide more specific and clinically relevant information when compared with anatomical imaging.     

Is <Superscript>18</Superscript>F-FDG PET/CT useful for the differential diagnosis of solitary pulmonary nodules in patients with idiopathic pulmonary fibrosis?

Objective

Idiopathic pulmonary fibrosis (IPF) is associated with an increased incidence of lung cancer, but patients with IPF often have poor pulmonary function and are vulnerable to pneumothorax and so using an invasive procedure to diagnose a single nodule detected on chest CT risks a critical adverse outcome. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) is recognized to be useful for differentiating between benign and malignant solitary pulmonary nodules (SPN) in patients without IPF, but its diagnostic accuracy has not been investigated in patients with IPF. In this study, therefore, we investigated whether ¹⁸F-FDG PET/CT is useful for the differential diagnosis of SPNs in patients with IPF.

Methods

From the IPF patient cohort of our institution, we retrospectively reviewed 55 patients (54 men, 1 woman; age 67.8?±?7.6 years) with an SPN sized 8–30 mm (mean 18.5?±?5.7 mm) who underwent chest CT followed by ¹⁸F-FDG PET/CT between April 2004 and March 2016. The ¹⁸F-FDG uptake of the SPN was analyzed visually and semiquantitatively, and these determinations were compared with the final diagnosis obtained by pathology (n?=?52) or imaging follow-up (n?=?3).

Results

The final diagnoses showed that 41 (75%) of the SPNs were malignant (21 squamous cell carcinomas, 9 adenocarcinomas, 5 small-cell carcinomas, 4 mixed-type carcinomas, 1 large-cell neuroendocrine carcinoma, and 1 sarcoid carcinoma) and 14 (25%) were benign. The determination of malignant SPNs by visual analysis of the PET/CT images had a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 98, 86, 95, and 92%, respectively. The semiquantitative analysis using a maximum standardized uptake value of 2.0 as the cut-off had a sensitivity, specificity, PPV, and NPV of 95, 93, 98, and 87%, respectively.

Conclusions

¹⁸F-FDG PET/CT is useful for differentiating benign and malignant SPNs in patients with IPF, as it is for patients without IPF.

     

The feasibility of <Superscript>18</Superscript>F-FES and <Superscript>18</Superscript>F-FDG microPET/CT for early monitoring the effect of fulvestrant on sensitizing docetaxel by downregulating ERα in ERα+ breast cancer

Objective

Our study aimed to investigate the feasibility of PET/CT for monitoring the influence of fulvestrant on sensitizing docetaxel by downregulating ERα in ERα+ breast cancer.

Methods

Docetaxel-insensitive ERα+ breast cancer cells (DIS-ZR751) were established, identified and cultured. ERα expression, toxicity and viability of DIS-ZR751 were analyzed before and after treatment in vitro. DIS-ZR751-bearing nude mice were randomly divided into four groups according to different treatments: blank (DIS-ZR751), docetaxel (DIS-ZR751+DOC), fulvestrant (DIS-ZR751+FUL), and combination treatment (DIS-ZR751+DOC+FUL). ¹⁸F-FES and ¹⁸F-FDG microPECT/CT scans were performed before and 7, 14 days after treatment. Absolute %ID/g_max was calculated.

Results

ERα expression level and growth rate of DIS-ZR751 were higher than control group and decreased dramatically after docetaxel and fulvestrant combination treatment. ¹⁸F-FES and ¹⁸F-FDG PET/CT imaging in vivo revealed that ERα expression in DIS-ZR751 treated with fulvestrant, and tumor activity in DIS-ZR751 treated with combination drugs decreased as early as 7 days after treatment.

Conclusions

¹⁸F-FES and ¹⁸F-FDG PET/CT were feasible for early monitoring the effect of fulvestrant on sensitizing docetaxel by downregulation of ERα in ERα+ breast cancer noninvasively.

     

Comparison of <Superscript>99m</Superscript>Tc-labeled PR81 and its F(ab′)<Subscript>2</Subscript> fragments as radioimmunoscintigraphy agents for breast cancer imaging

Objective  

We digested anti-MUC1 monoclonal antibody PR81 to produce F(ab′)₂ fragments. A comparison was performed between the two radiolabeled PR81 and F(ab′)₂ fragments for breast tumor imaging in a mouse model.     

Assessment of alveolar epithelial permeability in Behçet’s disease with <Superscript>99m</Superscript>Tc-DTPA aerosol scintigraphy

Objective

Behçet’s disease (BD) is a multisystem disorder characterized by vasculitis, and consists of a triad of recurrent ulcers of the oral and genital mucosa with relapsing uveitis. The prevalance of pulmonary involvement varies in the range of 1–10% in various studies and its complications are severe and life threatening. In this study, we investigated the changes of pulmonary epithelial permeability of patients with BD using technetium-99m diethylene triamine penta-acetic acid (^99mTc-DTPA) aerosol scintigraphy, so as to begin the therapy regimen as soon as possible.

Methods

Twenty-one nonsmoking patients with BD (8 women, 13 men; mean age 38.67 ± 8.86 years) and 15 healthy volunteer nonsmoking controls (8 women, 7 men; mean age 50.87 ± 12.45 years) underwent ^99mTc-DTPA aerosol inhalation scintigraphy and pulmonary function tests (PFTs). Subjects inhaled 1480 MBq of ^99mTc-DTPA for 4 min in the supine position. Scintigraphic data were recorded dynamically (1 frame/min) in the posterior projection on a 64 × 64 matrix for a 30-min period using a double-headed gamma camera (Infinia, GE, Tirat Hacarmel, Israel) equipped with a low-energy all-purpose parallel hole collimator. Half time of ^99mTc-DTPA clearance (T _1/2) was calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was also calculated by dividing the peripheral total counts by the sum of the peripheral and central total counts on the first minute image, in order to quantify the distribution of the inhaled aerosol.

Results

The clearance half time of ^99mTc-DTPA radioaerosols in the BD patients (24.81 ± 6.22 min) was faster than in the normal control group (46.53 ± 22.41 min) (P = 0.004). There was also a significant difference between PI of the patients with BD (0.15 ± 0.03) and that of the controls (0.21 ± 0.06) (P = 0.002). No correlation was found between the mean T _1/2 values of ^99mTc-DTPA clearance or the spirometric measurements in the BD patients. Penetration indices were not correlated with PFT in the BD patients.

Conclusions

Lung epithelial permeability of the patients with BD was significantly higher than that of the normal subjects. The results of this study demonstrated that the assessment of lung epithelial permeability using ^99mTc-DTPA aerosol scintigraphy could predict the presence of lung involvement in the early stages of BD.

     

Is prophylactic embolization of the hepatic falciform artery needed before radioembolization in patients with <Superscript>99m</Superscript>Tc-MAA accumulation in the anterior abdominal wall?

Purpose  

While influx of chemoembolic agents into the hepatic falciform artery (HFA) from the hepatic artery can cause supraumbilical skin rash, epigastric pain and even skin necrosis, the significance of a patent HFA in patients undergoing radioembolization is not completely clear. Furthermore, the presence of tracer in the anterior abdominal wall seen in ^99mTc-macroaggregated albumin (^99mTc-MAA) images, which is generally performed prior to radioembolization, has been described as a sign of a patent HFA. The aim of this retrospective study was to evaluate the incidence and consequences of ^99mTc-MAA accumulation in the anterior abdominal wall, indicating a patent HFA, in patients undergoing radioembolization of liver tumours.     

Semiautomatic volume of interest drawing for <Superscript>18</Superscript>F-FDG image analysis—method and preliminary results

Purpose Functional imaging of cancer adds important information to the conventional measurements in monitoring response. Serial ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET), which indicates changes in glucose metabolism in tumours, shows great promise for this. However, there is a need for a method to quantitate alterations in uptake of FDG, which accounts for changes in tumour volume and intensity of FDG uptake. Selection of regions or volumes [ROI or volumes of interest (VOI)] by hand drawing, or simple thresholding, suffers from operator-dependent drawbacks. Materials and methods We present a simple, robust VOI growing method for this application. The method requires a single seed point within the visualised tumour and another in relevant normal tissue. The drawn tumour VOI is insensitive to the operator inconsistency and is, thus, a suitable basis for comparative measurements. The method is validated using a software phantom. We demonstrate the use of the method in the assessment of tumour response in 31 patients receiving chemotherapy for various carcinomas. Results Valid assessment of tumour response could be made 2–4 weeks after starting chemotherapy, giving information for clinical decision making which would otherwise have taken 9–12 weeks. Survival was predicted from FDG-PET 2–4 weeks after starting chemotherapy (p = 0.04) and after 9–12 weeks FDG-PET gave a better prediction of survival (p = 0.002) than CT or MRI (p = 0.015). Conclusions FDG-PET using this method of analysis has potential as a routine tool for optimising use of chemotherapy and improving its cost effectiveness. It also has potential for increasing the accuracy of response assessment in clinical trials of novel therapies.     

Imaging α<Subscript>v</Subscript>β<Subscript>3</Subscript> integrin expression in skeletal metastases with <Superscript>99m</Superscript>Tc-maraciclatide single-photon emission computed tomography: detection and therapy response assessment

Purpose

Osteoclast activity is an important factor in the pathogenesis of skeletal metastases and is a potential therapeutic target. This study aimed to determine if selective uptake of ^99mTc-maraciclatide, a radiopharmaceutical targeting α_vβ₃ integrin, occurs in prostate cancer (PCa) bone metastases and to observe the changes following systemic therapy.

Methods

The study group comprised 17 men with bone-predominant metastatic PCa who underwent whole-body planar and single-photon emission computed tomography/computed tomography (SPECT/CT) imaging with ^99mTc-maraciclatide before (n?=?17) and 12 weeks after (n?=?11) starting treatment with abiraterone. Tumour to normal bone (T:N) ratios, tumour to muscle (T:M) ratios and CT Hounsfield units (HU) were measured in up to five target metastases in each subject. An oncologist blinded to study scans assessed clinical responses up to 24 weeks using conventional criteria.

Results

Before treatment, metastases showed specific ^99mTc-maraciclatide accumulation (mean planar T:N and T:M ratios 1.43 and 3.06; SPECT T:N?and T:M ratios 3.1 and 5.19, respectively). Baseline sclerotic lesions (389–740 HU) showed lower T:M ratios (4.22 vs. 7.04, p?=?0.02) than less sclerotic/lytic lesions (46–381 HU). Patients with progressive disease (PD; n?=?5) showed increased planar T:N and T:M ratios (0.29 and 12.1%, respectively) and SPECT T:N and T:M ratios (11.9 and 20.2%, respectively). Patients without progression showed decreased planar T:N and T:M ratios (0.27 and ?8.0%, p?=?1.0 and 0.044, respectively) and SPECT T:N and T:M ratios (?21.9, and ?27.2%, p?=?0.3 and 0.036, respectively). The percentage change in CT HU was inversely correlated with the percentage change in SPECT T:M ratios (r?=??0.59, p?=?0.006).

Conclusions

^99mTc-maraciclatide accumulates in PCa bone metastases in keeping with increased α_vβ₃ integrin expression. Greater activity in metastases with lower CT density suggests that uptake is related to osteoclast activity. Changes in planar and SPECT T:M ratios after 12 weeks of treatment differed between patients with and without PD and ^99mTc-maraciclatide imaging may be a potential method for assessing early response.

     

Evaluation of <Superscript>99m</Superscript>Tc-TRODAT-1 SPECT in the diagnosis of Parkinson’s disease versus other progressive movement disorders

Objective

Parkinson disease (PD), parkinsonian syndromes (PS) and essential tremor (ET) are different types of movement disorders which share some symptoms resulting in a difficulty of certain diagnosis. This study was conducted to determine the value of ^99mTc-TRODAT-1 scan to differentiate PD from ET and other PS cases.

Methods

Totally, 75 patients were studied including 29 PD, 6 possible PD, 22 ET and 18 PS cases. A dual-head SPECT-CT was used to perform basal ganglia (BG) imaging following administration of ^99mTc-TRODAT-1. The BG uptake values were normalized to whole brain and occipital activity. All patients were followed for 2–22 months to reach a certain diagnosis.

Results

Patients with ET and drug-induced parkinsonism show significantly higher normalized BG uptake as compared to the other subgroups; however, no significant difference was noted between PD and PS patients. The sensitivity and specificity of the findings for the differentiation between patients with the disease associated versus not associated with BG dysfunction were 80 and 83.3 %, respectively. A predictive positive value of 82.6 % was obtained using an additive scaling index defined as asymmetry and unevenness of uptake in putamen and/or caudate contralateral to the dominant side of current symptoms.

Conclusions

^99mTc-TRODAT-1 scan is an appropriate method to differentiate PD or PS versus ET. A combination of scan pattern including asymmetry of BG uptake and unevenness of activity in caudate and putamen along with the side of dominant symptoms may be valuable for the differentiation of Parkinson’s disease from the other parkinsonian syndromes.

     

Performance evaluation of the DrugWipe<Superscript>®</Superscript> 5/5<Superscript>+</Superscript> on-site oral fluid screening device

This study presents a retrospective performance evaluation of an on-site oral fluid drug screening device DrugWipe® 5/5⁺ (Securetec). The results obtained by the device were compared with gas chromatography–mass spectrometry confirmation analysis results in whole blood. Data used in the comparison were based on 1,807 real cases in which the Finnish police had conducted an on-site drug test on persons suspected of driving under the influence of drugs. The present data cover only cases wherein the DrugWipe device has shown a positive result for at least one substance. The data were compiled from the databases of Alcohol and Drug Analytics Unit at the National Institute for Health and Welfare. The performance of the DrugWipe was evaluated for its relevant drug groups: amphetamines, cannabis, opiates, and cocaine. The evaluation was carried out by calculating the sensitivity, specificity, and accuracy as well as the positive and negative predictive values. These calculations were based on the classification of the results as true positives, false positives, true negatives, and false negatives. Additionally, the demographics of the cases and analytical findings in whole blood are discussed. According to this study, the DrugWipe device performed quite well in detecting amphetamines, the most frequently encountered group of illicit drugs in Finnish traffic. The performance of the cannabis, opiate, and cocaine tests was not at the same level.     

Dopamine transporter SPECT using fast kinetic ligands: <Superscript>123</Superscript>I-FP-β-CIT versus <Superscript>99m</Superscript>Tc-TRODAT-1

A comparative study was carried out on two promising presynaptic dopamine transporter single-photon emission tomography (SPECT) radioligands with a fast pharmacokinetic profile, ¹²³I-FP--CIT (FP) and ^99mTc-TRODAT-1 (TR), in order to assess their differential diagnostic power in early parkinsonism and their sensitivity for detection of disease progression. This cross-sectional study was conducted on 96 patients with early-stage parkinsonism referred in a tertiary clinical setting. Mean disease duration was 2.0±1.3 years, and patients had a modified Hoehn and Yahr (H&Y) stage of 1–2 (average 1.2). Forty-seven patients received TR, and 49 received FP. In both groups, ten patients with normal presynaptic function were included as a control population; all other patients were clinically diagnosed as having idiopathic Parkinsons disease. Groups were matched for gender, age, disease duration and modified H&Y stage. Triple-head gamma camera SPECT was analysed using a semiquantitative index of transporter binding (BI). Discriminant analysis with cross-validation resulted in a maximal classification accuracy for FP of 93% (sensitivity 95% and specificity 86%) for the contralateral putamen BI. For TR, the corresponding values were 87% accuracy, 92% sensitivity and 70% specificity. For FP, disease duration was correlated with both the putamen BI (–8.8%/year, =–0.41, P=0.025) and the putamen/caudate ratio (–7.4%/year, =–0.51, P=0.004), but for TR no significant correlation was found (all P values >0.5). In conclusion, both FP and TR show high sensitivity in a clinically relevant setting, but FP has superior accuracy for early differential diagnosis of idiopathic parkinsonism and non-degenerative extrapyramidal disorders, as well as better sensitivity for disease follow-up.     

<Superscript>18</Superscript>p-FDG PET is superior to<Superscript>67</Superscript>Ga SPECT in the staging of non-Hodgkin’s lymphoma

OBJECTIVE: Our study aims to compare diagnostic accuracy between 18F-FDG PET and 67Ga SPECT in the staging of non-Hodgkin's lymphoma. METHODS: Twenty-eight patients with non-Hodgkin's lymphoma, underwent 18F-FDG PET, 67Ga SPECT and CT for the pretreatment staging of malignant lymphoma between August 1999 and March 2002. 18F-FDG PET imaging was obtained 60 minutes after the intravenous administration of 185 MBq of 18F-FDG. 67Ga SPECT imaging was obtained 2 days after the intravenous administration of 148 MBq of 67Ga. 18F-FDG PET and 67Ga SPECT were performed within one month. Both imagings were performed on the area from the neck to the pelvis. The 18F-FDG PET and 67Ga SPECT findings were compared with the CT findings and the clinical course. RESULTS: Sixty-six nodal lesions were clinically confirmed. Of these, 32 were identified by both 18F-FDG PET and 67Ga SPECT. The remaining 34 lesions were identified only by 18F-FDG PET. The mean (+/- SD) sizes' of the nodes were 34.7 +/- 32.4 mm for 18F-FDG-positive and 67Ga-positive lesions and 15.7 +/- 8.3 mm for 18F-FDG-positive and 67Ga-negative lesions (p < 0.001). Of the 23 extranodal lesions, 12 were identified by both 18F-FDG PET and 67Ga SPECT, whereas 6 lesions were identified by only 18F-FDG PET. Five lesions were not identified by either technique. No 18F-FDG-negative but 67Ga-positive nodal or extranodal lesions were observed. The difference in findings between the two studies is related to the difference in the size but not in the histology or site of the lesions. CONCLUSION: 18F-FDG PET detected significantly more lesions particularly small lesions than 67Ga SPECT. Thus, 18F-FDG PET is considered to be superior to 67Ga SPECT in the staging of non-Hodgkin' s lymphoma.     

Could <Superscript>99m</Superscript>Tc-glucarate be used to evaluate tumour necrosis?

PURPOSE: The aim of this study was to determine whether (99m)Tc-glucarate ((99m)Tc-GLA) is a powerful and discriminant tumour necrosis marker. MATERIALS AND METHODS: The induction of apoptosis and secondary necrosis (by a chemotherapeutic agent) and necrosis (by intense hyperthermia) was studied on an in vitro and in vivo leukaemic cell line model (U937). The percentage of apoptosis/necrosis in vitro was determined by flow cytometry after staining cells with annexin-V-fluorescein/propidium iodide. The uptake of (99m)Tc-GLA was studied after treatments that produce an optimal of necrosis cells or apoptotic cells. Three populations of interest: viable, apoptotic and necrotic cells were sorted by flow cytometry. The uptake and the intracellular distribution of (99m)Tc-GLA on each population have been studied. We also investigated the influence of necrosis on (99m)Tc-GLA uptake in a model of U937 xenografts in nude mice. RESULTS: The accumulation of (99m)Tc-GLA in untreated and apoptotic cells was lower than in necrotic cells. Cell sorting discriminated each cellular population and showed a 14% accumulation in necrotic cells and no more than a 3% in apoptotic cells. In apoptotic and viable cells, (99m)Tc-GLA is distributed between the cytosolic/membrane and the nucleus fractions. In necrotic cells, (99m)Tc-GLA is mainly found in the nucleus fraction. In vivo investigations showed a higher (99m)Tc-GLA uptake in necrotic tumour than in apoptotic and control ones. CONCLUSIONS: (99m)Tc-GLA may be a useful agent to specifically evaluate tumour necrosis and may be helpful for the follow-up of patients with cancer.