High-activity samarium-153-EDTMP therapy followed by autologous peripheral blood stem cell support in unresectable osteosarcoma

PURPOSE

Despite highly efficacious chemotherapy, patients with osteosarcomas still have a poor prognosis if adequate surgical control cannot be obtained. These patients may benefit from therapy with radiolabeled phosphonates.

PATIENTS AND METHODS

Six patients (three male, three female; seven to 41 years) with unresectable primary osteosarcoma (n = 3) or unresectable recurrent sites of osteosarcomas (n = 3) were treated with high-activity of Sm-153-EDTMP (150 MBq/kg BW). In all patients autologous peripheral blood stem cells had been collected before Sm-153-EDTMP therapy.

RESULTS

No immediate adverse reactions were observed in the patients. In one patient bone pain increased during the first 48 hrs after therapy. Three patients received pain relief. Autologous peripheral blood stem cell reinfusion was performed on day +12 to +27 in all patients to overcome potentially irreversible damage to the hematopoietic stem cells. In three patient external radiotherapy of the primary tumor site was performed after Sm-153-EDTMP therapy and in two of them polychemotherapy was continued. Thirty-six months later one of these patients is still free of progression. Two further patients are still alive. However, they have developed new metastases. The three patients who had no accompanying external radiotherapy, all died of disease progression five to 20 months after therapy.

CONCLUSION

These preliminary results show that high-dose Sm-153-EDTMP therapy is feasible and warrants further evaluation of efficacy. The combination with external radiation and polychemotherapy seems to be most promising. Although osteosarcoma is believed to be relatively radioresistant, the total focal dose achieved may delay local progression or even achieve permanent local tumor control in patients with surgically inaccessible primary or relapsing tumors.

FDG-PET for detection of pulmonary metastases from malignant primary bone tumors: comparison with spiral CT

BACKGROUND

The purpose was the comparison of positron emission tomography using F-18-fluorodeoxy-glucose (FDG-PET) and spiral thoracic CT to detect pulmonary metastases from malignant primary osseous tumors.

PATIENTS AND METHODS

In 71 patients with histologically confirmed malignant primary bone tumors (32 osteosarcomas, 39 Ewing's sarcomas) 111 FDG-PET examinations were evaluated with regard to pulmonary/pleural metastases in comparison with spiral thoracic CT. Reference methods were the clinical follow-ups for 6-64 months (median 20 months) or a histopathologic analysis.

RESULTS

In 16 patients (23%) reference methods revealed a pulmonary/pleural metastatic disease. FDG-PET had a sensitivity of 0.50, a specificity of 0.98, and an accuracy of 0.87 on a patient based analysis. Comparable values for spiral CT were 0.75, 1.00, and 0.94. It was shown that no patient who had a true positive FDG-PET had a false negative CT scan, nor was a pulmonary metastases detected earlier by FDG-PET than by spiral CT.

CONCLUSIONS

There seems to be a superiority of spiral CT in the detection of pulmonary metastases from malignant primary bone tumors as compared with FDG-PET. Therefore, at present a negative FDG-PET cannot be recommended to exclude lung metastases. However, as specificity of FDG-PET is high, a positive FDG-PET result can be used to confirm abnormalities seen on thoracic CT scans as metastatic.

Changes in cerebral glucose metabolism and visuospatial capability in hypogonadal males under testosterone substitution therapy

Genders differ concerning abilities of spatial cognition; positive associations of testosterone levels with corresponding scores have been reported, as well. We addressed the question whether there is a testosterone-susceptible area within cerebral structures previously described to be involved in mental rotation. Using F-18-deoxyglucose (FDG)-positron emission tomography (PET), we studied cerebral glucose metabolism during a standardized 3-dimensional mental rotation task in 6 right-handed men with hypogonadotropic hypogonadism before and under testosterone substitution therapy. Under elevated testosterone levels, enhanced cerebral glucose metabolism during mental rotation was observed in the 4 subjects with improved visuospatial capability. Areas involved were previously demonstrated to be activated by such tasks in eugonadal men.

[Clinical value of positron emission tomography (PET) in the diagnosis of bone and soft tissue tumors. 3rd Interdisciplinary Consensus Conference "PET in Oncology": results of the Bone and Soft Tissue Study Group]

PURPOSE

In the framework of the 3rd Consensus Conference "PET in Oncology" the bone and soft-tissue tumors study group evaluated the present position of PET for these tumor entities on the basis of international publications.

METHODS

After a systematic review of the literature, publications were evaluated according to previously defined quality criteria. For various indications the clinical usefulness of PET was assessed using a classification system.

RESULTS

Most studies had been performed with a small number of patients (n < 35). Therefore, only 8 of 46 publications were judged relevant. On the basis of these literature data, use of FDG-PET for grading was classified 1b (literature results predominantly show clinical usefulness). As before (1995/97), all other indications were categorized with 3 (assessment not yet possible, literature data inadequate).

OUTLOOK

According to the opinion of experts, the detection of osseous metastases of Ewing's sarcoma, therapy monitoring and the diagnosis of recurrences are potentially useful clinical indications for FDG-PET. Therefore, prospective studies with large patient groups are essential to further evaluate the benefit of FDG-PET in these indications.

Disturbed benzodiazepine receptor function at the onset of temporal lobe epilepsy--lomanzenil-binding in de-novo TLE

PURPOSE

Epileptogenic foci exhibit disturbed function at the level of the benzodiazepine receptor. The aim of our study was to investigate the incidence of focal reductions of temporal benzodiazepine receptor binding (BRB) as assessed by scintigraphy with 123I-iomazenil in patients with denovo temporal lobe epilepsy (TLE).

METHODS

Forty adult patients (age: 34+/-12 years) with cryptogenic denovo TLE underwent scintigraphy with 123I-iomazenil. In all patients, symptomatic epilepsy was excluded by clinical investigation and MRI. The median duration of TLE was seven months, and the patients had a median of three documented seizures in their history of disease. BRB was quantified in four temporal regions covering the whole temporal lobe. Temporal asymmetry values (ASY) were compared with data determined in 13 age-matched controls yielding Z-scores for global and regional temporal BRB.

RESULTS

A significant reduction of temporal BRB was found in 19 of the 40 patients (48 %), mainly in mesial temporal regions; temporal BRB asymmetries were also found in patients with a short history of seizures and low seizure frequency (< or = 1 year; n = 32, 13/32 (41 %)). Only in the entire cohort did the magnitude of temporal reduction of BRB correlate with the duration of TLE as well as with the number of previous partial seizures (r = 0.40 and r = 0.36; p < 0.03, respectively).

CONCLUSIONS

Foci of decreased BRB can already be detected at the onset of TLE; their magnitude is related to ongoing epileptic activity.

Whole-body MR imaging for detection of bone metastases in children and young adults: comparison with skeletal scintigraphy and FDG PET

OBJECTIVE

The purpose of this study was to compare the diagnostic accuracy of whole-body MR imaging, skeletal scintigraphy, and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for the detection of bone metastases in children.

SUBJECTS AND METHODS

Thirty-nine children and young adults who were 2--19 years old and who had Ewing's sarcoma, osteosarcoma, lymphoma, rhabdomyosarcoma, melanoma, and Langerhans' cell histiocytosis underwent whole-body spin-echo MR imaging, skeletal scintigraphy, and FDG PET for the initial staging of bone marrow metastases. The number and location of bone and bone marrow lesions diagnosed with each imaging modality were correlated with biopsy and clinical follow-up as the standard of reference.

RESULTS

Twenty-one patients exhibited 51 bone metastases. Sensitivities for the detection of bone metastases were 90% for FDG PET, 82% for whole-body MR imaging, and 71% for skeletal scintigraphy; these data were significantly different (p < 0.05). False-negative lesions were different for the three imaging modalities, mainly depending on lesion location. Most false-positive lesions were diagnosed using FDG PET.

CONCLUSION

Whole-body MR imaging has a higher sensitivity than skeletal scintigraphy for the detection of bone marrow metastases but a lower sensitivity than FDG PET.

[Role of FDG-PET in oncological surgery]

Fluorine-18 fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) allows in vivo analysis of tissue metabolic activity. Based on the observation that most malignant tumors display a higher metabolic activity than benign tissues, [18F]FDG-PET offers an interesting option for the diagnosis of primary and recurrent malignant tumors. For the oncological surgeon [18F]FDG-PET is particularly helpful for the diagnosis of tumors of the pancreas, colorectum, lung and esophagus. This short review describes the biological basis of [18F]FDG-PET and gives a critical discussion of its role in oncological surgery.

Temporal hypometabolism at the onset of cryptogenic temporal lobe epilepsy

Most patients with intractable temporal lobe epilepsy (TLE) exhibit temporal glucose hypometabolism. The reasons for the development of this abnormality are as yet unclear. The current notion is that an initial injury causes seizures, which in turn give rise to hypometabolism. The aim of this study was to assess whether temporal reductions in glucose metabolism in non-lesional TLE are the result of repeated seizures or whether hypometabolism represents an initial disturbance at the onset of disease. Glucose consumption was assessed with fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) in 62 patients with cryptogenic non-refractory TLE in different stages of disease. Twelve subjects without neurological illness served as controls. Patients with onset of epilepsy at least 3 years prior to the PET scan were defined as having chronic TLE. Using this criterion, the whole patient cohort included 27 patients with de novo TLE and 35 patients with chronic TLE. The groups were matched for age and sex. The appearance of high-resolution magnetic resonance images of the brain was unremarkable in all patients. In the total cohort, number, duration and frequency of seizures had a significant relation to the magnitude of hypometabolism. Temporal hypometabolism was exhibited by 26 of the 62 patients (42%), including 8 out of 27 (30%) with newly diagnosed TLE and 18 out of 35 (51%) with chronic TLE. The disturbances were more extensive and more severe in patients with chronic TLE. It is concluded that temporal hypometabolism may already be present at the onset of TLE, but is less frequent and less severe in newly diagnosed than in chronic TLE. The metabolic disturbance correlates with the number of seizures. These findings suggest that an initial dysfunction is present in a considerable number of patients and that hypometabolism is worsened by continuing epileptic activity.

FDG-PET for detection of pulmonary metastases from malignant primary bone tumors: comparison with spiral CT

BACKGROUND

The purpose was the comparison of positron emission tomography using F-18-fluorodeoxy-glucose (FDG-PET) and spiral thoracic CT to detect pulmonary metastases from malignant primary osseous tumors.

PATIENTS AND METHODS

In 71 patients with histologically confirmed malignant primary bone tumors (32 osteosarcomas, 39 Ewing's sarcomas) 111 FDG-PET examinations were evaluated with regard to pulmonary/pleural metastases in comparison with spiral thoracic CT. Reference methods were the clinical follow-ups for 6-64 months (median 20 months) or a histopathologic analysis.

RESULTS

In 16 patients (23%) reference methods revealed a pulmonary/pleural metastatic disease. FDG-PET had a sensitivity of 0.50, a specificity of 0.98, and an accuracy of 0.87 on a patient based analysis. Comparable values for spiral CT were 0.75, 1.00, and 0.94. It was shown that no patient who had a true positive FDG-PET had a false negative CT scan, nor was a pulmonary metastases detected earlier by FDG-PET than by spiral CT.

CONCLUSIONS

There seems to be a superiority of spiral CT in the detection of pulmonary metastases from malignant primary bone tumors as compared with FDG-PET. Therefore, at present a negative FDG-PET cannot be recommended to exclude lung metastases. However, as specificity of FDG-PET is high, a positive FDG-PET result can be used to confirm abnormalities seen on thoracic CT scans as metastatic.

Kinetic parameters of 3-[(123)I]iodo-L-alpha-methyl tyrosine ([(123)I]IMT) transport in human GOS3 glioma cells

The radiolabelled amino acid 3-[(123)I]iodo-L-alpha-methyl tyrosine ([(123)I]IMT) is a promising tool for the diagnosis and monitoring of brain tumors using single-photon emission tomography (SPECT). However, little is known about the precise kinetics of [(123)I]IMT uptake in human glioma cells. The kinetic analysis of [(123)I]IMT transport in human GOS3 glioma cells yielded a high-affinity apparent Michaelis constant (K(m) = 20.1 +/- 1.5 microM). The maximum transport velocity (V(max)) amounted to 34.8 +/- 1.9 nmol/mg protein/10 min. Competitive inhibition experiments revealed that [(123)I]IMT transport is mediated principally by the sodium-independent system L.

High uptake of L-3-[123I]iodo-alpha-methyl tyrosine in pilocytic astrocytomas

Despite a favourable prognosis, pilocytic astrocytomas may exhibit signs of malignancy on various neuroimaging modalities. This retrospective analysis was conducted to determine whether scintigraphic features of malignancy are also found on single-photon emission tomography (SPET) using L-3-[123I]iodo-alpha-methyl tyrosine (IMT) as a tracer. Twenty patients with pilocytic astrocytomas were retrospectively selected from a large series of patients referred for the evaluation of primary or recurrent brain tumours. IMT SPET was performed in 16 patients, positron emission tomography (PET) using 2-[18F]fluoro-2-deoxy-D-glucose (FDG) was available in 10 of the patients and SPET using technetium-99m tetrofosmin or thallium-201 had been performed in 11. Image analysis was performed using standard protocols to determine how many patients exceeded the respective thresholds of malignancy. Features of malignancy were found in 7/16 IMT SPET studies, in 7/10 FDG PET studies and in 7/11 of the residual SPET investigations. A significant correlation of tumour size and IMT uptake in primary pilocytic astrocytomas indicated partial volume effects to partly account for the differential uptake behaviour (n = 10, r = 0.87, P < 0.05). Differences in IMT uptake in primaries (1.7 +/- 0.6, n = 10) and in recurrent tumours (2.3 +/- 0.7, n = 6) did not attain statistical significance. IMT SPET results indicative of malignancy are regularly found in pilocytic astrocytomas, despite their good prognosis. No uptake may be detected in largely cystic or in small tumours.

Pulmonary beta adrenoceptor density in arrhythmogenic right ventricular cardiomyopathy and idiopathic tachycardia

OBJECTIVE

In recent in vivo studies using positron emission tomography (PET) our group demonstrated that the myocardial beta adrenoceptor (betaAR) density is reduced in arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic right ventricular outflow tract tachycardia (RVO-VT) associated with an increased presynaptic catecholamine washout. It was hypothesised that the reduction of myocardial betaAR density is secondary to an increase of local catecholamines in the myocardium resulting from the presynaptic dysfunction since circulating plasma catecholamines were demonstrated to be unchanged in these conditions. To further prove this hypothesis of an organ-limited adrenergic nervous dysfunction of the heart, this study aimed to investigate betaAR density in another thoracic organ, the lung.

METHODS

Pulmonary and myocardial betaAR density was measured in 7 ARVC patients, 8 RVO-VT patients and in a group of healthy controls (n = 13) using the non-selective beta-blocker [11C]-CGP 12177 and PET.

RESULTS

Pulmonary betaAR density was similar in controls (12.4 +/- 1.7 pmol/g tissue), ARVC (11.6 +/- 1.7 pmol/g tissue, p = ns) and RVO-VT (12.8 +/- 2.0 pmol/g tissue, p = ns), whereas myocardial betaAR density was significantly reduced in ARVC (6.3 +/- 1.1 pmol/g tissue, p = 0.006) and RVO-VT (6.8 +/- 1.2 pmol/g tissue, p=0.02) as compared to controls (8.8+/-1.5 pmol/g tissue).

CONCLUSION

The unchanged pulmonary betaAR density in the presence of a previously described significant reduction in myocardial betaAR density in the same patient principally supports our pathophysiological hypothesis that the myocardial betaAR density may be reduced in ARVC and RVO-VT because of an increase in local synaptic catecholamine levels due to an organ-limited presynaptic adrenergic dysfunction of the heart. Since in the present study only pulmonary betaAR density was measured, future functional studies excluding pulmonary betaAR desensitisation are required to finally prove the unchanged pulmonary sympathetic innervation in ARVC and RVO-VT.

Signal characteristics of multichannel epicardial electrograms in chronic ischaemic and scarred myocardium: electromechanical mismatch indicates viability in regions of myocardial dysfunction

BACKGROUND

To predict the outcome after myocardial revascularisation, a clear separation between hibernation and/or repetitive stunning on the one hand and myocardial scarring on the other hand is of importance.

METHODS AND RESULTS

A total of 44 patients was included in this study. In 35 patients with chronic myocardial ischaemia and an indication for coronary bypass-surgery, epicardial mapping of local activation was performed. Nine patients with LV aneurysm and an indication for antitachycardia surgery were also included. For simultaneous recording of the local electrograms during sinus rhythm, a sock electrode with 102 bipolar leads was used. The regional myocardial contraction pattern was assessed from preoperative angiograms and regional myocardial metabolism (viability) from 18F-FDG PET, respectively. The results were projected on the grid of the intraoperative position of the sock electrode. This enabled regional comparison of electrogram characteristics to local contraction patterns and viability. For the characterisation of local electrograms, peak-to-peak amplitude and duration of activation were calculated using custom-made automated computer-algorithms. Dysfunctional but viable areas showed normal or almost normal electrographic signal characteristics. In contrast, dysfunctional and non-viable myocardium showed a distinct reduction of local amplitudes and prolongation of signal duration. These changes were even more intense in areas of LV aneurysms.

CONCLUSIONS

In patients with chronic ischaemic myocardium, a mismatch between mechanical function and local electrogram characteristics was observed in areas with preserved metabolism. Thus, normal epicardial electrograms in regions of myocardial dysfunction may be an indicator for myocardial viability.

Characterization of 3-[123I]iodo-L-alpha-methyl tyrosine ([123I]IMT) transport into human Ewing's sarcoma cells in vitro

3-[(123)I]Iodo-L-alpha-methyl tyrosine ([(123)I]IMT) scintigraphy of extracranial malignant tumors has been described, but little is known about the transport systems involved in [(123)I]IMT uptake into extracranial tumor cells. Here, the precise kinetics of [(123)I]IMT transport into human Ewing's sarcoma cells (VH-64) was determined. The apparent Michaelis constant was of high affinity value (K(m)=41.7+/-3.9 microM) and maximum transport velocitiy amounted to V(max)=20.7+/-0.6 nmol x mg protein(-1) x 10 min(-1). Inhibition experiments revealed the predominance of [(123)I]IMT uptake via sodium-independent system L.

Characterization of 3-[(123)I]iodo-L-alpha-methyl tyrosine transport in astrocytes of neonatal rats

3-[(123)I]Iodo-L-alpha-methyl tyrosine ((123)I-IMT) is used for diagnosis and monitoring of brain tumours by means of single-photon emission tomography. As recently shown, (123)I-IMT is predominantly mediated into rat C6 glioma cells by sodium-independent system L for large neutral amino acids. Until now, (123)I-IMT transport in non-neoplastic glial cells has not been examined. Therefore, the aim of this study was to examine the cellular pathways and precise transport kinetics of (123)I-IMT uptake into astrocytes of neonatal rats. In particular sodium-independent (123)I-IMT transport into neonatal astrocytes was compared with sodium-independent (123)I-IMT uptake into neoplastic rat C6 glioma cells. Competitive inhibition experiments showed that (123)I-IMT is exclusively transported via sodium-independent system L into the neonatal astrocytes (92%). Kinetic analysis of sodium-independent (123)I-IMT uptake into neonatal astrocytes and into C6 glioma cells revealed apparent Michaelis constants K(M) = 13.9 +/- 0.5 microM and K(M) = 33.9 +/- 4.1 microM, respectively, which are in the same range of K(M) values as those recently determined for amino acid transport into neoplastic and non-neoplastic glial cells. Indeed, the K(M) values in the micromolar range correspond to the expression of the LAT-1 subunit of system L both in the neonatal astrocytes and in C6 glioma cells. However, sodium-independent maximum transport velocities (V(max)) differed significantly between neonatal astrocytes and C6 glioma cells (11.1 +/- 0.3 and 39.9 +/- 3.3 nmol/mg protein/10 min, respectively).

Elastic surface contour detection for the measurement of ejection fraction in myocardial perfusion SPET

The aim of this study was to investigate the use of an automated three-dimensional myocardial contour detection method using elastic surfaces for the assessment of left ventricular ejection fraction (EF) from electrocardiographically (ECG) triggered myocardial perfusion single-photon emission tomography (SPET). The validity of this method was studied on the basis of both phantom measurements and patient studies. Phantom measurements were performed using an elastic phantom of the left ventricle simulating a beating heart, with a simulated EF ranging from 10% to 78%. The data from 27 patients who had undergone both ECG-triggered myocardial perfusion SPET and planar gated radionuclide ventriculography (RNV) were used to compare the EF derived from the SPET data with the automated contour detection method and the EF derived from the RNV data with standard analysis software. EF values as measured by RNV ranged from 11% to 68%. The overall accuracy of the automated contour detection method proved to be very high. In the phantom study the deviation of the measured EF from the reference values was less than 4% for all of the simulated EFs. The studies on the patient data yielded a correlation coefficient (Pearson) greater than 0.94 as compared with planar RNV. Intra- and inter-observer reproducibility was high, with correlation coefficients exceeding 0.97. It is concluded that the proposed method allows accurate, reproducible and fast measurement of the left ventricular EF on the basis of myocardial perfusion SPET.

Evaluation of chemotherapy response in primary bone tumors with F-18 FDG positron emission tomography compared with histologically assessed tumor necrosis

PURPOSE

The purpose of this study was to evaluate the potential of positron emission tomography using F-18-fluoro-2-deoxy-D-glucose (FDG PET) to assess the chemotherapy response of primary osseous tumors compared with the degree of necrosis determined histologically.

PATIENTS AND METHODS

Seventeen patients with primary bone tumors (11 osteosarcomas, 6 Ewing's sarcomas) were examined using FDG PET and planar bone scintigraphy before neoadjuvant chemotherapy and before surgery. Tumor response was classified histologically according to Salzer-Kuntschik (grades I-II: good response; grades IV-VI: poor response). In both imaging methods, quantification was performed using tumor to nontumor ratios (T:NT).

RESULTS

Histologically, 15 patients were classified as having good responses (grade I, n = 1; grade II, n = 6; grade III, n = 8) and two as having poor responses (grades IV and V). FDG PET showed more than a 30% decrease in T:NT ratios in all patients who had good responses. However, three of these patients had increasing bone scintigraphy T:NT ratios, and another five had decreasing ratios of less than 30%. The patients with poor responses had increasing T:NT ratios and decreasing ratios of less than 30%, respectively, using both imaging methods.

CONCLUSIONS

FDG PET seems to be a promising tool for evaluating the response of primary osseous tumors to chemotherapy. In this preliminary study, FDG PET was superior to planar bone scintigraphy.

[Nuclear medicine diagnosis of the liver]

Four types of radionuclide investigations are described here: 99mTc-labeled red blood cell scintigraphy, colloid liver scintigraphy, hepatobiliary scintigraphy, and positron emission tomography with [18F]fluorodeoxyglucose. The role of nuclear imaging techniques in the diagnosis of liver diseases has changed in recent years and now compliments morphological imaging modalities by offering the unique ability to visualize function and metabolism. The studies described here are therefore rarely performed now by themselves for the delineation of secondary liver tumors. These radionuclide investigations are used principally to narrow the differential diagnosis of focal liver disease.