Impact of [<Superscript>18</Superscript>F]FDG-PET on the primary staging of small-cell lung cancer

Purpose The purpose of this study was to evaluate the impact of [¹⁸F]fluorodeoxy-d-glucose positron emission tomography (FDG-PET) on the primary staging of patients with small-cell lung cancer (SCLC).Methods FDG-PET was performed in 120 consecutive patients with SCLC during primary staging. In addition, brain examinations with both FDG-PET and cranial magnetic resonance imaging (MRI) or computed tomography (CT) were performed in 91 patients. Results of FDG-PET were compared with those of conventional staging procedures. FDG-PET detected markedly increased FDG uptake in the primary tumours of all 120 patients (sensitivity 100%).Results Complete agreement between FDG-PET results and other staging procedures was observed in 75 patients. Differences occurred in 45 patients at 65 sites. In 47 sites the FDG-PET results were proven to be correct, and in ten, incorrect. In the remaining eight sites, the discrepancies could not be clarified. In 14/120 patients, FDG-PET caused a stage migration, correctly upstaging ten patients to extensive disease and downstaging three patients by not confirming metastases of the adrenal glands suspected on the basis of CT. Only 1/120 patients was incorrectly staged by FDG-PET, owing to failure to detect brain metastases. In all cases the stage migration led to a significant change in the treatment protocol. Sensitivity of FDG-PET was significantly superior to that of CT in the detection of extrathoracic lymph node involvement (100% vs 70%, specificity 98% vs 94%) and distant metastases except to the brain (98% vs 83%, specificity 92% vs 79%). However, FDG-PET was significantly less sensitive than cranial MRI/CT in the detection of brain metastases (46% vs 100%, specificity 97% vs 100%).Conclusion The introduction of FDG-PET in the diagnostic evaluation of SCLC will improve the staging results and affect patient management, and may reduce the number of tests and invasive procedures.     

Time-to-time correlation of high-risk atherosclerotic lesions identified with [18F]-FDG-PET/CT

Objective  It has been shown that [¹⁸F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) can identify macrophage-rich high-risk atherosclerotic plaques in animal models as well as in patients with atherosclerotic plaques in the carotid arteries. The development of inflamed macrophage-rich plaques over time is not well known. This study was performed to determine the variability of such FDG-accumulating plaques between consecutive PET/CT examinations. Methods  Twenty-eight patients who underwent two whole-body FDG-PET/CT examinations within 7 months for malignant diseases were re-evaluated for atherosclerotic lesions in major arterial segments. The plaques were identified as active, inactive, or mixed depending on their appearance on PET and CT. Every identified plaque was compared with that of the other examination to evaluate the time-to-time correlation. Results  The time-to-time correlation was close to 100% for calcified inactive plaques and about 50% for FDG-accumulating active plaques, with a high consistency between all examined arterial segments in this material. Conclusions  A large proportion of FDG-accumulating plaques can be identified on consecutive FDG-PET/CT examinations within 7 months.     

[<Superscript>18</Superscript>F]FDG-PET predicts complete pathological response of breast cancer to neoadjuvant chemotherapy

Purpose To evaluate, in breast cancer patients treated by neoadjuvant chemotherapy, the predictive value of reduction in FDG uptake with regard to complete pathological response (pCR). Methods Forty-seven women with non-metastatic, non-inflammatory, large or locally advanced breast cancer were included. Tumour uptake of FDG was evaluated before and after the first course of neoadjuvant chemotherapy. Four indices were used: maximal and average SUV without or with correction by body surface area and glycaemia (SUV_max, SUV_avg, SUV_max-BSA-G and SUV_avg-BSA-G, respectively). The predictive value of reduction in FDG uptake with respect to pCR was studied by logistic regression analysis. Relationships between baseline [¹⁸F]FDG uptake and prognostic parameters were assessed. Results The relative decrease in FDG uptake (ΔSUV) after the first course of neoadjuvant chemotherapy was significantly greater in the pCR group than in the non-pCR group (p < 0.000066). The four FDG uptake indices were all strongly correlated with each other. A decrease in SUV_max-BSA-G of 85.4% ± 21.9% was found in pCR patients, versus 22.6% ± 36.6% in non-pCR patients. ΔSUV_max-BSA-G <−60% predicted the pCR with an accuracy of 87% and ΔSUVs were found to be only factors predictive of the pCR at multivariate analysis. An elevated baseline SUV was associated with high mitotic activity (p < 0.0016), tumour grading (p < 0.004), high nuclear pleomorphism score (p < 0.03) and negative hormonal receptor status (p < 0.005). Conclusion In breast cancer patients, after only one course of neoadjuvant chemotherapy the reduction in FDG uptake is an early and powerful predictor of pCR.     

Improved Stability and Practicality for Synthesis of 4-Borono-2-[18F]fluoro-l-phenylalanine by Combination of [18O]O2 Single-Use and [18F]CH3COOF Labeling Agents

Purpose4-Borono-2-[¹⁸F]fluoro-l-phenylalanine ([¹⁸F]FBPA) synthesized with [¹⁸F]F₂, produced using the ¹⁸O(p, n)¹⁸F reaction, has been reported for increasing radioactivity. However, a dedicated system and complex procedure is required to reuse the costly [¹⁸O]O₂ gas; also, the use of [¹⁸F]F₂ as a labeling agent reduces the labeling rate and radiochemical purity. We developed a stable and practical method for [¹⁸F]FBPA synthesis by combining [¹⁸F]F₂, produced using a [¹⁸O]O₂ single-use system, and a [¹⁸F]CH₃COOF labeling agent.MethodsThe produced [¹⁸F]F₂ was optimized, and then [¹⁸F]FBPA was synthesized. For passivation of the target box, 0.5% F₂ was pre-irradiated in argon. Gaseous products were discarded; the target box was filled with [¹⁸O]O₂ gas, and then irradiated (first irradiation). Then, the [¹⁸O]O₂ gas was discarded, 0.05–0.08% F₂ in argon was fed into the target box, and it was again irradiated (second irradiation). The [¹⁸F]F₂ obtained after this was passed through a CH₃COONa column, converting it into the [¹⁸F]CH₃COOF labeling agent, which was then used for [¹⁸F]FBPA synthesis.ResultsThe mean amount of as-obtained [¹⁸F]F₂ was 55.0 ± 3.3 GBq and that of as-obtained [¹⁸F]CH₃COOF was 21.6 ± 1.4 GBq after the bombardment. The radioactivity and the radiochemical yield based on [¹⁸F]F₂ of [¹⁸F]FBPA were 4.72 ± 0.34 GBq and 12.2 ± 0.1%, respectively. The radiochemical purity and molar activity were 99.3 ± 0.1% and 231 ± 22 GBq/mmol, respectively.ConclusionWe developed a method for [¹⁸F]FBPA production, which is more stable and practical compared with the method using [¹⁸O]O₂ gas-recycling and [¹⁸F]F₂ labeling agent.     

Comparisons of [18F]-1-deoxy-1-fluoro-scyllo-inositol with [18F]-FDG for PET imaging of inflammation, breast and brain cancer xenografts in athymic mice

Introduction

The aim of the study was to evaluate the uptake of [¹⁸F]-1-deoxy-1-fluoro-scyllo-inositol ([¹⁸F]-scyllo-inositol) in human breast cancer (BC) and glioma xenografts, as well as in inflammatory tissue, in immunocompromised mice. Studies of [¹⁸F]-2-fluoro-2-deoxy-d-glucose ([¹⁸F]-FDG) under the same conditions were also performed.

Methods

Radiosynthesis of [¹⁸F]-scyllo-inositol was automated using a commercial synthesis module. Tumour, inflammation and normal tissue uptakes were evaluated by biodistribution studies and positron emission tomography (PET) imaging using [¹⁸F]-scyllo-inositol and [¹⁸F]-FDG in mice bearing subcutaneous MDA-MB-231, MCF-7 and MDA-MB-361 human BC xenografts, intracranial U-87 MG glioma xenografts and turpentine-induced inflammation.

Results

The radiosynthesis of [¹⁸F]-scyllo-inositol was automated with good radiochemical yields (24.6%±3.3%, uncorrected for decay, 65±2 min, n=5) and high specific activities (≥195 GBq/μmol at end of synthesis). Uptake of [¹⁸F]-scyllo-inositol was greatest in MDA-MB-231 BC tumours and was comparable to that of [¹⁸F]-FDG (4.6±0.5 vs. 5.5±2.1 %ID/g, respectively; P=.40), but was marginally lower in MDA-MB-361 and MCF-7 xenografts. Uptake of [¹⁸F]-scyllo-inositol in inflammation was lower than [¹⁸F]-FDG. While uptake of [¹⁸F]-scyllo-inositol in intracranial U-87 MG xenografts was significantly lower than [¹⁸F]-FDG, the tumour-to-brain ratio was significantly higher (10.6±2.5 vs. 2.1±0.6; P=.001).

Conclusions

Consistent with biodistribution studies, uptake of [¹⁸F]-scyllo-inositol was successfully visualized by PET imaging in human BC and glioma xenografts, with lower accumulation in inflammatory tissue than [¹⁸F]-FDG. The tumour-to-brain ratio of [¹⁸F]-scyllo-inositol was also significantly higher than that of [¹⁸F]-FDG for visualizing intracranial glioma xenografts in NOD SCID mice, giving a better contrast.     

Comparison of MET-PET and FDG-PET for differentiation between benign lesions and malignant tumors of the lung

OBJECTIVE: We retrospectively assessed and compared the usefulness of 11C-methionine (MET)-PET with that of 18F-FDG-PET for the differentiation between benign lesions and malignant tumors of the lung. METHODS: We examined 101 patients with a suspected lung tumor including 79 patients with primary lung cancer and 22 patients with benign lesions. One hundred and forty PET studies (46 studies with MET-PET and 94 studies with FDG-PET) were performed. Both MET-PET and FDG-PET were performed on 39 patients. The MET-PET was performed 15 minutes after the administration of 67-740 MBq of MET, and FDG-PET 45 minutes after the administration of 30-437 MBq of FDG. The results were then evaluated by the standardized uptake value (SUV). RESULTS: The MET uptake in lung cancer was 3.69+/-1.22 (n = 37) which was significantly higher than that in benign lesions 1.81+/-1.04 (n = 9) (p < 0.001). The sensitivity, specificity and accuracy of MET-PET were 83.8%, 88.9% and 84.8%, respectively, when 2.66 of SUV was used as the cutoff value. The FDG uptake in lung cancer was 5.94+/-2.89 (n = 75) and was also significantly larger than that in benign lesions 2.46+/-1.01 (n = 19) (p < 0.001). The sensitivity, specificity and accuracy of FDG-PET were 81.3%, 78.9% and 80.9%, respectively (cutoff = 3.20). The MET uptake in the lesions correlated significantly with FDG uptake (r = 0.71, p < 0.001). According to an ROC analysis, the area under the curve for MET-PET (area = 0. 833) was higher than that for FDG-PET (area = 0.828), but the difference was not statistically significant. Furthermore, the combined use of MET-PET and FDG-PET did not improve the diagnostic ability. CONCLUSIONS: In conclusion, both MET-PET and FDG-PET were considered to be equally useful for the differential diagnosis of lung tumors. Furthermore, MET uptake in lung lesions was found to correlate significantly with FDG uptake.     

Synthesis and tumour-localizing properties of [18F]-5-fluorocytosine-arabinoside and [18F]-5-fluorocyclocytidine

[¹⁸F]-5-fluorocytosine-arabinoside (2) and [¹⁸F]-5-fluorocyclocytidine (4) were prepared by reaction of [¹⁸F]-acetylhypofluorite with cytosine-arabinoside (1) or cyclocytidine (3) in acetic acid and were isolated in an overall radiochemical yield of 20% and 9%, respectively. The biodistribution of both radiopharmaceuticals was determined in melanoma bearing Syrian golden hamsters. It was found that 2 is a good tumour-localizing agent for pigmented and non-pigmented Greene melanoma.     

Comparison of [123I]metaiodobenzylguanidine kinetics with heart rate variability and plasma norepinephrine level

Background  [¹²³I]Metaiodobenzylguanidine (MIBG) imaging has been used to assess cardiac sympathetic nerve abnormalities. We evaluated the clinical significance of myocardial MIBG imaging as a measure of cardiac sympathetic nervous system function by comparing it to heart rate variability and plasma norepinephrine level. Methods and Results  In 211 subjects, we analyzed heart rate variability with 24-hour electrocardiography, performed scintigraphy with MIBG, and measured plasma norepinephrine levels. Time and frequency domain measures of heart rate variability were calculated with the Marquette heart rate variability program (Marquette Electronics, Milwaukee, Wis.). Early and late myocardial MIBG uptakes were measured at 15 and 150 minutes after injection, respectively. MIBG clearance rate from the heart and heart-to-lung and heart-to-mediastinum ratios of MIBG activities were calculated. On the whole, heart rate variability, including low-frequency power, correlated positively, but modestly so, with late MIBG uptake and negatively with MIBG clearance rate. The plasma norepinephrine level correlated negatively with late MIBG uptake and with heart rate variability, including low-frequency power, and positively with MIBG clearance rate. Similar correlations were also observed in patient subgroups with coronary artery disease, diabetes mellitus, and renal failure, but these correlations were weak (R ²<0.5). Conclusions  Increased cardiac sympathetic nervous system activity may be associated with increased myocardial MIBG clearance and decreased heart rate variability, including low-frequency power. Because these associations were not strong, however, the combination of heart rate variability with MIBG may allow an interactive assessment of the cardiac autonomic nervous system.     

An automated synthesis module for preparation of -3-[I]iodo-alpha-methyl tyrosine

-3-[¹²³I]iodo-alpha-methyl tyrosine (IMT) is an artificial amino acid suitable for SPECT imaging of various tumours. Manual synthesis of this radiopharmaceutical is reliable, but time-consuming and may require handling of large quantities of radioactivity. We developed an automated IMT synthesis module, which prepares a ready-to-inject product that meets radiopharmaceutical requirements and is identical to the manually synthesised equivalent. Current advantages include decreased operator assistance time and reduced radiation exposure. Application may be extended to other radiopharmaceuticals, including high-dose preparations for therapeutic use.     

Thyroid cancer with a high 123I-NaI uptake in primary and metastatic foci with euthyroidism

A case of thyroid cancer showing both a high ¹²³I-NaI uptake in primary and metastatic foci with euthyroidism was reported. Extrathyroidal uptake of radioactive iodine is emphasized to be suggestive of metastases of thyroid cancer even in an euthyroid state.     

Application of I-123 HIPDM as a lung imaging agent

N,N,N-Trimethyl-N-(2-Hydroxyl-3-Methyl-5-¹²³I Iodobenzyl)-1,3-Propanediamine · Hcl (¹²³I-HIPDM) has been used for diagnosis of patients with strokes and dementias. Since this radiopharmaceutical is also accumulated in the lung, we routinely performed a lung image or images immediately prior to cerebral planar and SPECT images after a 3–5 mCi ¹²³I-HIPDM injection. During the past 14 months, we obtained 78 (age from 41 to 92 years, average 66.7±8.9 years; 64 males, 14 females) suspected stroke or dementia patients' lung images. All lung images were correlated to chest X-ray (CXR) or CT and other clinical data. Sixty five of 78 patients had normal lungs showing homogeneous distribution of activity throughout the lungs which correlated well to normal CXR and/or CT studies. Abnormal scintigraphic patterns of the 13 patients included lung defect (5 bronchogenic carcinoma with or without atelectasis) and decreased uptake in apices (8 chronic obstructive pulmonary disease). The findings of pulmonary intrathoracic pathologies on lung images with ¹²³I-HIPDM suggests further evaluation of the agent for detection of localized pulmonary diseases and pulmonary physiological studies relating to amine metabolism.This investigation was supported in part by Biomedical Research Support Grant no. RR05374 from the Biomedical Research Support Branch, Division of Research Facilities and Resources, NIH     

NanoPET imaging of [18F]fluoromisonidazole uptake in experimental mouse tumours

Purpose The purpose of this study was to assess the potential and utility of ultra-high-resolution hypoxia imaging in various murine tumour models using the established hypoxia PET tracer [¹⁸F]fluoromisonidazole ([¹⁸F]FMISO).Methods [¹⁸F]FMISO PET imaging was performed with the dedicated small-animal PET scanner NanoPET (Oxford Positron Systems) and ten different human tumour xenografts in nude mice as well as B16 melanoma tumours in syngeneic Balb/c mice. For comparison, [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) PET scans were also performed in the mice bearing human tumour xenografts.Results In 10 out of 11 experimental tumour models, [¹⁸F]FMISO PET imaging allowed clear-cut visualisation of the tumours. Inter- and intratumoural heterogeneity of tracer uptake was evident. In addition to average TMRR (tumour-to-muscle retention ratio including all voxels in a volume of interest (VOI)), the parameters TMRR_75% and TMRR₅ (tumour-to-muscle retention ratio including voxels of 75% or more of the maximum radioactivity in a VOI and the five hottest pixels, respectively) also served as measures for quantifying the heterogeneous [¹⁸F]FMISO uptake in the tumours. The variability observed in [¹⁸F]FMISO uptake was related neither to tumour size nor to the injected mass of the radiotracer. The pattern of normoxic and hypoxic regions within the human tumour xenografts, however, correlated with glucose metabolism as revealed by comparison of [¹⁸F]FDG and [¹⁸F]FMISO images.Conclusion This study demonstrates the feasibility and utility of [¹⁸F]FMISO for imaging murine tumour models using NanoPET.     

Modeling pulmonary kinetics of 2-deoxy-2-[18F]fluoro-D-glucose during acute lung injury

RATIONALE AND OBJECTIVES: Dynamic positron emission tomographic imaging of the radiotracer 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) is increasingly used to assess metabolic activity of lung inflammatory cells. To analyze the kinetics of (18)F-FDG in brain and tumor tissues, the Sokoloff model has been typically used. In the lungs, however, a high blood-to-parenchymal volume ratio and (18)F-FDG distribution in edematous injured tissue could require a modified model to properly describe (18)F-FDG kinetics. MATERIALS AND METHODS: We developed and validated a new model of lung (18)F-FDG kinetics that includes an extravascular/noncellular compartment in addition to blood and (18)F-FDG precursor pools for phosphorylation. Parameters obtained from this model were compared with those obtained using the Sokoloff model. We analyzed dynamic PET data from 15 sheep with smoke or ventilator-induced lung injury. RESULTS: In the majority of injured lungs, the new model provided better fit to the data than the Sokoloff model. Rate of pulmonary (18)F-FDG net uptake and distribution volume in the precursor pool for phosphorylation correlated between the two models (R(2)=0.98, 0.78), but were overestimated with the Sokoloff model by 17% (P< .05) and 16% (P< .0005) compared to the new one. The range of the extravascular/noncellular (18)F-FDG distribution volumes was up to 13% and 49% of lung tissue volume in smoke- and ventilator-induced lung injury, respectively. CONCLUSION: The lung-specific model predicted (18)F-FDG kinetics during acute lung injury more accurately than the Sokoloff model and may provide new insights in the pathophysiology of lung injury.     

Role of [18F]FDG-PET/CT after radiofrequency ablation of liver metastases: preliminary results

PURPOSE: Focal metastasis may be treated with radiofrequency ablation (RFA), a low invasive method yet limited by the lack of direct evidence of radicality of treatment. We, hereby, aimed at assessing the role of positron emission tomography-computed tomography (PET/CT) with fluoride radiolabeled deoxy-glucose ([(18)F]FDG) in RFA treatment success evaluation and early diagnosis of local relapse of liver metastasis after RFA procedure. METHODS: RFA was performed in nine patients on 12 liver metastasis, serially imaged through [(18)F]FDG-PET/CT and multidetector CT (MDCT) at 1, 3, 6, and 9 months after treatment. Eight lesions were also scanned with [(18)F]FDG-PET/CT at 1 week after treatment. Imaging analyses were performed on 47 [(18)F]FDG-PET/CT and 51 MDCT. Imaging reading outcomes were compared to each other and to biopsy tissue results when available. RESULTS: In one case, [(18)F]FDG-PET/CT revealed radiotracer uptake at RFA site a week after procedure. Negative concordant outcome was obtained on eight lesions at 1 month after RFA, on eight cases at 3 months, on four at 6 months, and on two cases at 9 months. Extra-liver (peritoneal) disease was detected in one case by both [(18)F]FDG-PET/CT and MDCT. In seven cases, [(18)F]FDG-PET/CT revealed the presence of local recurrence earlier than MDCT. In no cases did MDCT detect local relapse earlier than [(18)F]FDG-PET/CT. CONCLUSION: [(18)F]FDG-PET/CT may detect RFA treatment failure as well as local relapse after RFA earlier than MDCT.     

Comparison of18FDG-PET with99mTc-HMDP scntigraphy for the detection of bone metastases in patients with breast cancer

OBJECTIVE: Bone is one of the most common sites of metastasis in breast cancer patients. Although bone scintigraphy is widely used to detect metastatic breast cancer, the usefulness of 18FDG-PET for detecting bone metastasis has not been clearly evaluated. The purpose of this study was to compare the diagnostic accuracy of 18FDG-PET with bone scintigraphy in detecting bone metastasis in breast cancer patients. METHODS: Forty-four women aged 35 to 81 years (mean, 56 years) with breast cancer were examined in this study. Both 18FDG-PET and bone scintigraphy were performed for each patient with 0-69 day intervals (mean, 11.5 days). The results of each image interpretation were compared retrospectively. Whole-body bones were classified into 9 anatomical regions. Metastases were confirmed at 45/187 regions in 14 patients by bone biopsy or clinical follow-up including other imaging techniques for a period of at least 6 months afterwards. RESULTS: On a region basis, the sensitivity, specificity, and accuracy of 18FDG-PET were 84%, 99% and 95%, respectively. Although these results were comparable to those of bone scintigraphy, the combination of 18FDG-PET and bone scintigraphy improved the sensitivity (98%) and accuracy (97%) of detection. False negative lesions of bone scintigraphy were mostly bone marrow metastases and those of 18FDG-PET were mostly osteoblastic metastases. 18FDG-PET was superior to bone scintigraphy in the detection of osteolytic lesions (92% vs. 73%), but inferior in the detection of osteoblastic lesions (74% vs. 95%). CONCLUSIONS: This study shows that 18FDG-PET tends to be superior to bone scintigraphy in the detection of osteolytic lesions, but inferior in the detection of osteoblastic lesions. 18FDG-PET should play a complementary role in detecting bone metastasis with bone scintigraphy.     

Comparison of the biodistribution of two hypoxia markers [<Superscript>18</Superscript>F]FETNIM and [<Superscript>18</Superscript>F]FMISO in an experimental mammary carcinoma

The first aim of this study was to compare the hypoxia imaging ability of fluorine-18 fluoroerythronitroimidazole ([¹⁸F]FETNIM) with that of fluorine-18 fluoromisonimidazole ([¹⁸F]FMISO) in murine tumours of different sizes under two different oxygenation conditions. Secondly, we wanted to assess the biodistribution of the markers in normal tissues under similar conditions. Female CDF1 mice with a C3H mammary carcinoma grown on their backs were used. Tumours were size matched and animals breathed either normal air (21% O₂) or carbogen gas (95% O₂ + 5% CO₂). The gassing procedure was begun 5 min before the intravenous injection of either [¹⁸F]FETNIM or [¹⁸F]FMISO and continued until the mice were sacrificed at 120 min. Blood, tumour, muscle, heart, lung, liver, kidney and fat were removed, counted for radioactivity and weighed. The tumour and muscle were frozen and cut with a cryomicrotome into sections. The spatial distribution of radioactivity from the tissue sections was determined with digital autoradiography. Estimation of the necrotic fraction was made on sections from formalin-fixed tumours. Digital autoradiography showed that the whole tumour-to-muscle radioactivity uptake ratios were significantly higher in normal air-breathing mice than in carbogen-treated mice for both [¹⁸F]FETNIM (4.9±2.6 vs 1.8±0.5; P<0.01) and [¹⁸F]FMISO (4.4±1.0 vs 1.5±0.4; P<0.01). The carbogen treatment had only slight effects on the biodistribution of either marker in normal tissues. The necrotic fraction determined in tumours did not correlate with the tumour volume or with the tumour-to-muscle radioactivity uptake ratio. This study shows that the uptake of both [¹⁸F]FETNIM and [¹⁸F]FMISO correlates with the oxygenation status in tumours. In addition, our data show no significant difference in the intratumoral uptake between the two markers. However, significantly higher radioactivity uptake values were measured for [¹⁸F]FMISO than for [¹⁸F]FETNIM in normal tissues.     

Positron emission tomography changes management and prognostic stratification in patients with oesophageal cancer: results of a multicentre prospective study

Objectives  The aims of this study were (1) to determine the incremental information provided by ¹⁸F-FDG positron emission tomography (PET) in staging patients with oesophageal cancer, and (2) to determine the impact of PET staging on post-PET clinical management of oesophageal cancer, and on prognosis. Methods  In a multicentre, single-arm open study, patients with proved oesophageal cancer without definite distant metastases and regarded as suitable for potentially curative treatment were examined by PET. Clinicians were requested to supply a management plan before and another plan after being supplied with the PET scan results. Patients were followed for at least 1 year for outcome analysis. Results  A total of 129 patients (104 men, mean age 67 y) were recruited. PET detected additional sites of disease in 53 patients (41%). Significant changes in management (high or medium impact) were observed in 38% of patients, primarily as a result of identifying additional sites of disease and/or confirming previously equivocal regional and distant metastases. Progression-free survival was significantly shorter in patients found to have additional lesions on PET (p < 0.05), but was not related to SUV_max. Conclusion  These findings demonstrate the significant impact of PET on the clinical management of patients with newly diagnosed oesophageal carcinoma, and on prognostic stratification of these patients. This work was presented in abstract form at the SNM Annual Meeting 2007: J Nucl Med 2007;48 (Supplement 2):26P.     

Tumour hypoxia imaging with [18F]FAZA PET in head and neck cancer patients: a pilot study

Purpose Hypoxia is an important negative prognostic factor for radiation treatment of head and neck cancer. This study was performed to evaluate the feasibility of use of ¹⁸F-labelled fluoroazomycin arabinoside ([¹⁸F]FAZA) for clinical PET imaging of tumour hypoxia. Methods Eleven patients (age 59.6 ± 9 years) with untreated advanced head and neck cancer were included. After injection of approximately 300 MBq of [¹⁸F]FAZA, a dynamic sequence up to 60 min was acquired on an ECAT HR+ PET scanner. In addition, approximately 2 and 4 h p.i., static whole-body PET (n = 5) or PET/CT (n = 6) imaging was performed. PET data were reconstructed iteratively (OSEM) and fused with CT images (either an external CT or the CT of integrated PET/CT). Standardised uptake values (SUVs) and tumour-to-muscle (T/M) ratios were calculated in tumour and normal tissues. Also, the tumour volume displaying a T/M ratio >1.5 was determined. Results Within the first 60 min of the dynamic sequence, the T/M ratio generally decreased, while generally increasing at later time points. At 2 h p.i., the tumour SUV_max and SUV_mean were found to be 2.3 ± 0.5 (range 1.5–3.4) and 1.4 ± 0.3 (range 1.0–2.1), respectively. The mean T/M ratio at 2 h p.i. was 2.0 ± 0.3 (range 1.6–2.4). The tumour volume displaying a T/M ratio above 1.5 was highly variable. At 2 h p.i., [¹⁸F]FAZA organ distribution was determined as follows: kidney > gallbladder > liver > tumour > muscle > bone > brain > lung. Conclusion [¹⁸F]FAZA PET imaging appears feasible in head and neck cancer patients, and the achieved image quality is adequate for clinical purposes. Based on our initial results, [¹⁸F]FAZA warrants further evaluation as a hypoxia PET tracer for imaging of cancer.