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R Bares

Publications and source records attributed to R Bares.

At least 19 recordsLinked to original sources
PubMed2002

FDG PET for staging of advanced non-small cell lung cancer prior to neoadjuvant radio-chemotherapy.

The aim of this study was to evaluate positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) for the staging of non-small cell lung cancer (NSCLC) before combined neoadjuvant, i.e. preoperative, radio-chemotherapy (RCT). From November 1998 until September 2001, 101 patients with NSCLC were investigated prospectively. The inclusion criterion was a histologically proven NSCLC of stage IIIA or B according to conventional staging including biopsy. The results of PET were compared with those obtained by mediastinoscopy, computed tomography (CT), bone scan and abdominal ultrasonography. Validation of discrepant findings was achieved by biopsy or repeated CT. PET proved to be highly accurate for the detection of lymph node metastases (sensitivity 96%, specificity 73%, positive predictive value 88%, negative predictive value 89%, accuracy 88%) as well as distant metastases (in 25/101 patients, all previously unknown). PET findings changed further treatment in 29/101 patients (29%). Twenty-five were excluded from RCT due to the presence of previously unknown distant metastases. One patient was free of metastases and therefore was operated on without pre-treatment. Two patients did not receive any further treatment because a malignant tumour could be excluded after PET. In the final patient PET demonstrated a tumour pattern not typical for NSCLC which could be attributed to a seminoma after repeated biopsy. FDG PET is the most accurate non-invasive diagnostic procedure for the staging of advanced NSCLC. Therefore use of FDG PET is highly recommended in order to select patients for neoadjuvant or other stage-dependent treatment modalities.

Adult↗
PubMed2002

Early prediction of treatment response to high-dose salvage chemotherapy in patients with relapsed germ cell cancer using [(18)F]FDG PET.

To assess the ability of [(18)F]fluorodeoxyglucose positron emission tomography for the early prediction of response in patients with relapsed metastatic germ cell tumours undergoing salvage high-dose chemotherapy. The role of positron emission tomography was compared with established means of tumour response assessment such as CT scans/MRI and serum tumour marker changes. In addition, positron emission tomography was compared with a current prognostic score which differentiates three prognostic groups with failure-free survival rates ranging from 5-50%. [(18)F]fluorodeoxyglucose uptake of metastases from germ cell tumours as well as CT scans and serum tumour marker were acquired after 2-3 cycles of induction chemotherapy but before the start of high-dose chemotherapy and CT scans/serum tumour marker were compared with the baseline examinations in 23 patients with relapsed germ cell tumours. To evaluate the validity of early response prediction by positron emission tomography, radiological monitoring and serum tumour marker decline, histopathologic response after resection of residual masses and/or the clinical course over 6 months after the end of treatment (relapse vs freedom of progression) were used. Overall, 10 patients (43%) achieved a marker-negative partial remission, three (13%) a marker-positive partial remission, five (22%) a disease stabilization and five (22%) progressed during treatment. Nine patients (39%) remained progression-free over 6 months following treatment, whereas 14 (61%) progressed. The outcome of high-dose chemotherapy was correctly predicted by positron emission tomography/CT scan/serum tumour marker in 91/59/48%. Eight patients with a favourably predicted outcome by CT scans plus serum tumour marker but a positive positron emission tomography prior to high-dose chemotherapy, failed treatment. This results in the following sensitivities/specificities for the prediction of failure of high-dose chemotherapy: positron emission tomography 100/78%; radiological monitoring 43/78%; serum tumour marker 15/100%. The positive and negative predictive values of positron emission tomography were 88 and 100%, respectively. As compared with the prognostic score, positron emission tomography was correctly positive in all patients of the three risk groups who failed treatment. In addition, a negative positron emission tomography correctly predicted a favourable outcome in the good and intermediate group. [(18)F]fluorodeoxyglucose positron emission tomography imaging can be used to assess response to chemotherapy in patients with relapsed germ cell tumours early in the course of treatment and may help to identify patients most likely to achieve a favourable response to subsequent high-dose chemotherapy. In patients with response to induction chemotherapy according to CT scans or serum tumour marker evaluation, positron emission tomography seems to add information to detect patients with an overall unfavourable outcome. It may also be a valuable addition to the prognostic model particularly in the good and intermediate group for further selection of patients who will profit from high-dose chemotherapy.

Adult↗
PubMed2001

Rhenium-188 for inhibition of human aortic smooth muscle cell proliferation.

PURPOSE: To evaluate dose-dependent growth-modulating effects of the beta-gamma emitter Rhenium-188 on cultured human aortic smooth muscle cells (haSMC). METHODS AND MATERIALS: HaSMC were plated in 25 cm(2) flasks. Two days after plating, cells were incubated with the Re-188 (beta E(max) 2.12 MeV, tissue range(max) < 10 mm, T(1/2) 17 h) for five days. The doses administered were 0.2 Gy, 1, 4, 6, 8, 16, and 32 Gy. After five days, the radionuclide was removed. Cell growth, cell cycle distribution, and clonogenic activity were analyzed for the following 25 days. RESULTS: The 0.2 and 1 Gy groups did not show relevant growth-inhibiting effects compared to the control groups. The 4 to 32 Gy groups presented dose-dependent growth inhibition, with a complete growth arrest of the 16 and 32 Gy groups. Clonogenic activity of the smooth muscle cell was strongly inhibited from doses > or =8 Gy. Flow cytometry showed a lasting dose-dependent G2/M phase block. CONCLUSION: Smooth muscle cell (SMC) growth can be controlled effectively with Re-188 for at least 25 days after radiation in vitro. As the first four weeks after arterial angioplasty are crucial concerning neointimal formation, Re-188 may be a valuable radionuclide to inhibit restenosis after arterial angioplasty.

Aorta↗
PubMed2001

[Dose-dependent effects of the combined beta/gamma emitter 186-Rhenium on the growth of human vessel wall cells].

PURPOSE: The aim of this study was to evaluate the capability of human aortic smooth musc e cells (HaSMC) and endothelial cells (EC) to recover after incubation with the combined beta/gamma emitter 186rhenium. MATERIALS AND METHODS: Two days after plating, HaSMC and EC were incubated for five days with 186Re (total doses applied 4 Gy-32 Gy). Cell counts were performed for a period of 30 days (haSMC) and 22 days (EC). To detect possible growth recovery, colony formation assays were plated for both cell types on day 5, 10, and 20 (and lay 30 for haSMC). RESULTS: Both cell types presented a dose-dependent growth inhibition which was maximum at a dose of 32 Gy. Human endothelial cells presented with total growth recovery at 4 and 8 Gy, and a partial growth recovery at 16 Gy. Smooth muscle cells only presented partial growth recovery at 4 and 8 Gy. At 16 Gy and more no recovery was detected. CONCLUSION: HaSMC as well as EC growth can be modulated effectively with 186Re over a period of 30 days in vitro. Compared to smooth muscle cells human endothelial cellls seem to possess a higher potential to recover at doses of 8 to 16 Gy. 186Re may be a valuable radionuclide to prevent restenosis.

Angioplasty, Balloon↗
PubMed2001

Neuroimaging in alcoholism: ethanol and brain damage.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The co-chairs were Karl Mann and Ingrid Agartz. The presentations were (1) Neuropathological changes in alcohol-related brain damage, by Clive Harper; (2) Regional brain volumes including the hippocampus and monoamine metabolites in alcohol dependence, by Ingrid Agartz, Susan Shoaf, Robert R, Rawlings, Reza Momenan, and Daniel W Hommer; (3) Diffusion tensor abnormalities in imaging of white matter alcoholism, by Adolf Pfefferbaum and Edith V. Sullivan; (4) Use of functional MRI to evaluate brain activity during alcohol cue exposure in alcoholics: Relationship to craving, by Raymond F. Anton, David J. Drobes, and Mark S. George; and (5) mu-Opiate receptor availability in alcoholism: First results from a positron emission tomography study, by Karl Mann, Roland Bares, Hans-Juergen Machulla, Goetz Mundle, Matthias Reimold, and Andreas Heinz.

Alcoholism↗
PubMed2001

Local intra-arterial drug delivery for prevention of restenosis: comparison of the efficiency of delivery of different radiopharmaceuticals through a porous catheter.

RATIONALE AND OBJECTIVES: Several radiopharmaceuticals were administered through a porous balloon catheter to compare the absolute amount deposited and the retention in the vessel wall. The reported efficiency of local drug delivery ranges from 0.001% to 0.1%, with poor retention after 24 hours. METHODS: An endothelin derivative (n = 6), pertechnetate (n = 6), hexamethylpropylene amineoxime (HMPAO) (n = 5), ethyl cysteinate dimer (ECD) (n = 5), and tin colloid (n = 5) were labeled with 185 MBq/mL 99m-technetium. After balloon denudation of the infrarenal aorta in 27 New Zealand White rabbits, 100 microL of each agent was administered through a porous balloon at a pressure of 4 bar. Dynamic and static whole-body scintigrams were obtained for 24 hours. The infrarenal aorta was excised and the activity calculated in a gamma counter. RESULTS: Apart from their retention in the region of local administration, the radiopharmaceuticals showed different distribution patterns. The highest regional tracer retention was observed with HMPAO. After administration of HMPAO, a significant difference between regional (vessel wall plus surrounding tissue: 14.5% of injected dose [ID]/24 hours) and local (vessel wall: 1.8% ID/24 hours) delivery was found. In contrast, ECD was eliminated quickly (local retention after 24 hours = 0% ID). The retention efficiencies were HMPAO > endothelin derivative > tin colloid > pertechnetate > ECD. CONCLUSIONS: The different physicochemical and pharmacokinetic properties of radiopharmaceuticals resulted in different delivery efficiencies after local application.

Animals↗
PubMed2001

Follow-up in neuroblastoma: comparison of metaiodobenzylguanidine and a chimeric anti-GD2 antibody for detection of tumor relapse and therapy response.

Early and correct diagnosis of local tumor recurrence, occurrence of metastases, and therapy response are essential in patients with neuroblastoma stage IV. The aim of the study was to evaluate the diagnostic value of metaiodobenzylguanidine (mIBG) and a chimeric GD2 antibody in the follow-up of patients with neuroblastoma. In a prospective study, mIBG (N = 31 scans) and immunoscintigraphy were compared with a chimeric antiganglioside antibody, ch14.18 (MAb) (N = 31 scans), labeled with technetium Tc 99m in the follow-up of 18 patients with stage IV neuroblastoma. The findings were compared with histologic findings, other imaging examinations, and clinical changes over the course of 4 to 6 years. For the diagnosis of local tumor recurrences, sensitivity was 80% for MAb and 70% for mIBG. Specificity was 93% for MAb and 72% for mIBG. The MAb was superior for the detection of skeletal metastases, with a sensitivity of 82% compared with 72% for mIBG. Specificity was 100% for both techniques. Also, for soft tissue/lymph node metastases, sensitivity for MAb was higher (50%) than for mIBG (31%). Specificity was 100% for each technique. In sequential studies, metastases were detected earlier with MAb (mean: 2.3 m for skeletal metastases, 3.6 m for soft tissue metastases) than with mIBG. After therapy, tumor uptake was visualized longer with mIBG (mean 6.3 m) than with MAb. The chimeric antibody ch14.18 is likely to be valuable for follow-up examinations and for assessment of therapy response because of earlier detection of new metastases.

3-Iodobenzylguanidine↗
PubMed2001

Prognostic significance of positron emission tomography using fluorine-18-fluorodeoxyglucose in patients treated for malignant lymphoma.

AIM: To evaluate the prognostic significance of positron emission tomography (PET) using fluorine-18-[2]-fluoro-2-deoxyglucose (FDG) in patients treated for Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) compared to conventional restaging (CRS). METHODS: Fifty-six patients with either HD (n = 22), high-grade NHL (n = 26) or centrocytic-centroblastic NHL (n = 8) were included. PET was performed in 41 patients for treatment reevaluation up to three months after therapy and in patients with persisting residual masses (n = 10) or suspected relapse (n = 5) four to twelve months after treatment. The scans were evaluated qualitatively and quantitatively using standardised uptake values (SUV). Progression-free survival (PFS) was estimated to assess the prognostic value of FDG PET and clinical follow-up was taken as gold standard. RESULTS: PET was positive in nineteen of 41 patients studied for treatment reevaluation. Progression was observed after a median interval of two months (range 0-15) in sixteen of 19 patients after a positive PET scan and in three of 22 patients after a negative scan (p < .001). Median duration of follow-up in progression-free patients was 21 months (range 6-72). In patients with a partial remission in CRS progression was more common in PET-positive than in PET-negative patients (5 of 7 vs. 1 of 14; p < .01) and positivity with PET was associated with poorer PFS (p < .0025). PET studies performed four to twelve months after treatment were true negative in seven, true positive in five and false-positive in three patients. SUV > 11.35 of lymphoma lesions was associated with poorer PFS than SUV < 11.35 (p < 0.025). CONCLUSION: We conclude that FDG PET after treatment of malignant lymphoma has a high prognostic value and should be recommended in patients with persistence of residual masses.

Adolescent↗
PubMed2001

Assessment of porcine bone metabolism by dynamic.

UNLABELLED: The aim of this study was to quantify regional bone blood flow and [(18)F]fluoride ion influx with [(18)F]fluoride ion PET and correlate the results with specific static and dynamic indices of bone metabolism in healthy pigs. METHODS: During continuous ventilation (fractional concentration of oxygen in inspired gas = 0.3), dynamic PET scans 120 min in duration were obtained for 9 mini pigs after intravenous injection of 10.0 +/- 1.2 MBq (mean +/- SD) of [(18)F]fluoride ion per kilogram of body weight. Iliac crest bone biopsies were performed immediately before the PET scan to determine static and dynamic indices of bone metabolism (i.e., the mineral apposition rate) by bone histomorphometry. Kinetic rate constants describing influx (K(1)) and efflux (k(2)) of [(18)F]fluoride as well as chemisorption and incorporation of [(18)F]fluoride (k(3)) and reverse transport (k(4)) were determined for 6 vertebral bodies in each animal. Blood flow estimates (f) were derived from K(1) values corrected for the permeability-surface area product using a previously derived correction algorithm. A rate constant describing the net forward transport rate of fluoride (K(i)) and the fluoride volume flux (K(flux)) derived from a 2-tissue-compartment model was calculated and compared with the results of Patlak graphic analysis (K(pat)). RESULTS: A significant correlation was found between mineral apposition rate and K(i) (P < 0.005), K(flux) (P < 0.01), K(pat), K(1), and f (P < 0.05). The values of f, K(i), K(flux), and K(pat) did not correlate significantly with other static or dynamic histomorphometric indices or with age, serum alkaline phosphatase, or parathyroid hormone levels. The values of f and K(i) correlated linearly (y = 0.023 + 0.32x; r(2) = 0.74; P < 0.001). CONCLUSION: PET bone studies using [(18)F]fluoride ion provide quantitative estimates of bone blood flow and metabolic activity that correlate with histomorphometric indices of bone formation in the normal bone tissue of the mini pig. Therefore, it seem reasonable to assume that [(18)F]fluoride ion PET can reduce the number of invasive bone biopsies, thus facilitating follow-up of patients with metabolic bone diseases.

Animals↗
PubMed2000

[Nuclear medicine diagnosis of the kidneys].

BACKGROUND: Renal studies have a long tradition in nuclear medicine and are available for routine use for more than 30 years. Their high clinical acceptance is mainly based upon the fact that they allow for quantitative evaluation of different functional parameters such as glomerular filtration, effective renal plasma flow, or postrenal transport. The used methods are validated by experimental as well as numerous clinical studies and are performed throughout the world in a highly standardized way. INDICATIONS: Indications are verification/exclusion of a disturbed renal function, detection or evaluation of renal artery stenosis, and differential diagnosis of urinary tract obstruction. Further diagnostic improvement might be achieved by use of positron emission tomography which has the potential for absolute quantification of physiological parameters such as renal blood flow in ml.min-1.100 g-1 tissue.

Glomerular Filtration Rate↗
PubMed2000

Dependency of the [18F]fluoromisonidazole uptake on oxygen delivery and tissue oxygenation in the porcine liver.

We have previously shown that the accumulation of fluorine-18-labeled fluoromisonidazole ([(18)F]FMISO) is inversely correlated to tissue oxygenation, allowing the quantification of porcine liver tissue hypoxia in vivo. We determined the activity from administered [(18)F]FMISO in relation to the hepatic oxygen availability and the partial pressure of oxygen in tissue (tPO(2)) to define a critical oxygen delivery on a regional basis. [(18)F]FMISO was injected 2 h after onset of regional liver hypoxia due to arterial occlusion of branches of the hepatic artery in 10 domestic pigs. During the experimental procedure the fractional concentration of inspired oxygen (FiO(2)) was set to 0.67 in group A ( N=5) and to 0.21 in group B ( N=5) animals. Immediately before sacrifice, the tPO(2) was determined in normal flow and flow-impaired liver segments. The standardized uptake values (SUV) for [(18)F]FMISO was calculated from 659 single tissue samples obtained 3 h after injection of approximately 10 MBq/kg body weight [(18)F]FMISO and was compared with the regional total hepatic oxygen delivery (DO(2)) calculated from the regional arterial and portal venous flow (based on (141)Ce- and (99m)Tc-microspheres measurements) and the oxygen content of the arterial and portal venous blood. In 121 tPO(2)-measured liver tissue samples, the mean DO(2) was significantly decreased in occluded liver tissue samples [group A: 0.063 (0.044-0.089); group B: 0.046 (0.032-0.066)] compared to normal flow segments [group A: 0.177 (0.124-0.252); group B: 0.179 (0.128-0.25) mL x min(-1) x g(-1); geometric mean (95% confidence limits); p < 0.01 in group A and p < 0.001 in group B]. The tPO(2) of occluded segments [group A: 5.1 (3.2-8.1); group B: 3.9 (2.4-6.2) mm Hg] was significantly decreased compared to normal flow segments [group A: 20.2 (12.6-32.5); group B: 22.4 (14.3-35.2) mm Hg; p < 0.01 in group A and p < 0.001 in group B]. Three hours after [(18)F]FMISO administration, the mean [(18)F]FMISO SUV determined in tPO(2)-measured occluded segments was significantly higher [group A: 4.08 (3.12-5.34), group B: 5.43 (4.14-7.13)] compared to normal liver tissue [group A: 1.57 (1.2-2.06), group B: 1.5 (1.16-1.93); p < 0.001 for both groups]. The [(18)F]FMISO SUV allowed prediction of the tPO(2) with satisfying accuracy in hypoxic regions using the exponential regression curve [[(18)F]FMISO=1.05+6.7((-0.117 tPO(2))); r(2)=0.75; p < 0.001]. In addition, regardless of ventilation conditions, a significant exponential relationship between the DO(2) and the [(18)F]FMISO SUV was found ( r(2)=0.39, p < 0.001). Our results suggest that the reduction of the oxygen delivery below the critical range of 0.1-0.11 mL x min(-1) x g(-1) regularly causes liver tissue hypoxia. The severity of hypoxia is reflected by the [(18)F]FMISO accumulation and allows the in vivo estimation of the tPO(2) in hypoxic regions.

Animals↗
PubMed2000

Fluorodeoxyglucose positron emission tomography and the prognosis of pancreatic carcinoma.

BACKGROUND: Pancreatic carcinoma is associated with a poor prognosis. The aim of this study was to determine whether glucose metabolism in pancreatic cancer has prognostic significance for patients suffering from this disease. METHODS: The survival data of 52 patients with pancreatic carcinoma was correlated with the standardized uptake value (SUV) as a semiquantitative parameter of glucose metabolism, as determined with fluorodeoxyglucose positron emission tomography (FDG PET). A multivariate analysis, including SUV and accepted factors of prognosis, such as stage at presentation and tumor marker Ca 19-9, was performed to determine the prognostic value of FDG PET. RESULTS: The median survival in 26 patients with low SUV (< 6.1) was 9 months (95% confidence interval 6-12 months) vs. 5 months (95% confidence interval 4-6 months) in 26 patients with high SUV (> or = 6.1). Multivariate analysis revealed SUV and tumor marker Ca 19-9 as independent factors of prognosis in patients with pancreatic carcinoma. CONCLUSION: Glucose metabolism, as determined with FDG PET, provides additional prognostic information in patients with pancreatic carcinoma.

Adenocarcinoma↗
PubMed1999

[Bone marrow recovery after irradiation of the spine].

BACKGROUND: Imaging of bone marrow by radio labeled antibodies against NCA-95 antigen of human granulocytes offers the possibility to visualize granulopoietic activity. After radiotherapy, a reduced uptake delineates the radiation field. Aim of our investigation was the study of strength and duration of this effect. PATIENTS AND METHODS: We analyzed 80 cases of patients irradiated for different primary or metastatic malignancies including parts of the spine who received a bone marrow scan for re-staging or during follow-up. Activity uptake of vertebrae inside and outside the irradiation portal was evaluated by ROI and the ratio was taken as measure of bone marrow suppression. RESULTS: A depression of granulopoietic bone marrow activity was seen even after a few fractions of 1.8 or 2 Gy (Figure 1). Depending on time since irradiation (Figure 2), we found a bone marrow recovery. In patients without bone metastasis, regeneration could be complete, whereas in patients treated for metastases, it was incomplete in all cases (Figure 3). CONCLUSIONS: For a certain time after irradiation, radioimmunoimaging delineates the irradiation portal by showing depression of granulopoiesis. Later on, it also shows bone marrow regeneration after radiotherapy. This may be helpful in reconstruction of radiation portals or in toxicity estimation during multimodal cancer therapy.

Adult↗
PubMed1999

Introducing fluorine-18 fluoromisonidazole positron emission tomography for the localisation and quantification of pig liver hypoxia.

Fluorine-18 labelled fluoromisonidazole ([18F]FMISO) has been shown to accumulate in hypoxic tissue in inverse proportion to tissue oxygenation. In order to evaluate the potential of [18F]FMISO as a possible positron emission tomography (PET) tracer for imaging of liver tissue hypoxia, we measured the [18F]FMISO uptake in 13 domestic pigs using dynamic PET scanning. Hypoxia was induced by segmental arterial hepatic occlusion. During the experimental procedure the fractional concentration of inspired oxygen (FiO2) was set to 0.67 in group A (n=6) and to 0.21 in group B (n=7) animals. Before and after arterial occlusion, the partial pressure of O2 in tissue (TPO2) and the arterial blood flow were determined in normal flow and flow-impaired liver segments. Standardised uptake values [SUV=kBq tissue (in g) / body weight (in kg) x injected dose (in kBq)] for [18F]FMISO were calculated from PET images obtained 3 hours after injection of about 10 MBq/kg body weight [18F]FMISO. Immediately before PET scanning, the mean arterial blood flow was significantly decreased in arterially occluded segments [group A: 0. 41 (0.32-0.52); group B: 0.24 (0.16-0.33) ml min-1 g-1] compared with normal flow segments [group A: 1.05 (0.76-1.46); group B: 1.14 (0.83-1.57) ml min-1 g-1; geometric mean (95% confidence limits); P<0.001 for both groups]. After PET scanning, the TPO2 of occluded segments (group A: 5.1 (4.1-6.4); group B: 3.5 (2.6-4.9) mmHg] was significantly decreased compared with normal flow segments [group A: 26.4 (21.2-33.0); group B: 18.2 (13.3-25.1) mmHg; P<0.001 for both groups]. During the 3-h PET scan, the mean [18F]FMISO SUV determined in occluded segments increased significantly to 3.84 (3.12-4.72) in group A and 5.7 (4.71-6.9) in group B, while the SUV remained unchanged in corresponding normal liver tissue [group A: 1.4 (1.14-1. 71); group B: 1.31 (1.09-1.57); P<0.001 for both groups]. Regardless of ventilation conditions, a significant inverse exponential relationship was found between the TPO2 and the [18F]FMISO SUV (r2=0. 88, P<0.001). Our results suggest that because tracer delivery to hypoxic tissues was maintained by the portal circulation, the [18F]FMISO accumulation in the liver was found to be directly related to the severity of tissue hypoxia. Thus, [18F]FMISO PET allows in vivo quantification of pig liver hypoxia using simple SUV analysis as long as tracer delivery is not critically reduced.

Animals↗
PubMed1999

Allogenic bone graft viability after hip revision arthroplasty assessed by dynamic [18F]fluoride ion positron emission tomography.

The biological fate of allogenic bone grafts in the acetabular cavity and their metabolic activity after acetabular augmentation is uncertain but is most important for the stability of hip implants after hip revision arthroplasty. The aim of this study was to quantify regional bone metabolism after hip replacement operations. Dynamic [18F]fluoride ion positron emission tomography (PET) was used to investigate the metabolic activity of acetabular allogenic bone grafts and genuine bone, either 3-6 weeks (short-term group, n = 9) or 5 months to 9 years (long-term group, n = 10) after hip revision arthroplasty. Applying a three-compartment model, the fluoride influx constant was calculated from individually fitted rate constants (Knlf) and by Patlak graphical analysis (Kpat). The results were compared with genuine cancellous and cortical acetabular bone of contralateral hips without surgical trauma (n = 7). In genuine cortical bone, Knlf was significantly increased in short- (+140.9%) and long-term (+100.0%) groups compared with contralateral hips. Allogenic bone grafts were characterised by a significantly increased Knlf in the short-term group (+190.9%) compared with contralateral hips, but decreased almost to the baseline levels of contralateral hips (+45.5%) in the long-term. Values of Knlf cor-related with the rate constant K1 in genuine (r = 0.89, P<0.001) and allogenic bone regions (r = 0.79, P<0.001), indicating a coupling between bone blood flow and bone metabolism in genuine bone as well as allogenic bone grafts. Kpat values were highly correlated with Knlf measurements in all regions. In conclusion, [18F]fluoride ion PET revealed the presence of an increased host bone formation in allogenic bone grafts early after hip revision arthroplasty. In contrast to genuine cortical bone, allogenic bone graft metabolism decreased over time, possibly due to a reduced ability to respond to the same extent as genuine bone to elevated metabolic demands after surgery.

Aged↗
PubMed1998

Treatment of neuroblastoma stage 4 with 131I-meta-iodo-benzylguanidine, high-dose chemotherapy and immunotherapy. A pilot study.

Disseminated neuroblastoma after infancy has a prognosis of approximately 10-20% with conventional therapy. We investigated the role of high-dose chemotherapy (HDCT) with peripheral blood stem cell (PBSC) rescue in combination with 131I-metaiodobenzylguanidine ([131I-m]IBG). 11 children with neuroblastoma stage 4 were pretreated within the German Neuroblastoma Trial NB90 and included in a high-dose concept for consolidation. Remission was documented by ultrasound, CT, NMR, or [123I-m]IBG scanning. HDCT was a combination of melphalan (180 mg/m2), carboplatin (1,500 mg/m2) and etoposide (40 mg/kg). All children were treated by [131I-m]IBG (0.58 GBq/kg) prior to high-dose treatment. All 11 children were additionally treated with antiGD2 murine- or chimeric-antibody (ch14.18). 4 children had no change to their remission status but three achieved a complete response (from a partial response to first line) and one a partial response (from no response to first line). The other 3 children progressed, 2 dying of their disease. Using Kaplan-Meier analysis, the probability of progression-free survival was 0.70 +/- 0.15 with a median observation time of 19 months. 9/11 children are alive, 8 without progression or relapse, whilst 2 have died of their disease. The combination of mIBG plus high-dose chemotherapy with PBSC support supplemented by immunotherapy with antiGD2 antibody appears to be a feasible and effective treatment regimen for disseminated neuroblastoma in this limited series. Larger numbers of patients should be treated to confirm these results.

3-Iodobenzylguanidine↗