Added Value of [18F]PSMA-1007 PET/CT and PET/MRI in Patients With Biochemically Recurrent Prostate Cancer: Impact on Detection Rates and Clinical Management.

BACKGROUND: Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) can change management in a large fraction of patients with biochemically recurrent prostate cancer (BCR). PURPOSE: To investigate the added value of PET to MRI and CT for this patient group, and to explore whether the choice of the PET paired modality (PET/MRI vs. PET/CT) impacts detection rates and clinical management. STUDY TYPE: Retrospective. SUBJECTS: 41 patients with BCR (median age [range]: 68 [55-78]). FIELD STRENGTH/SEQUENCE: 3T, including T1-weighted gradient echo (GRE), T2-weighted turbo spin echo (TSE) and dynamic contrast-enhanced GRE sequences, diffusion-weighted echo-planar imaging, and a T1-weighted TSE spine sequence. In addition to MRI, [18F]PSMA-1007 PET and low-dose CT were acquired on the same day. ASSESSMENT: Images were reported using a five-point Likert scale by two teams each consisting of a radiologist and a nuclear medicine physician. The radiologist performed a reading using CT and MRI data and a joint reading between radiologist and nuclear medicine physician was performed using MRI, CT, and PET from either PET/MRI or PET/CT. Findings were presented to an oncologist to create intended treatment plans. Intrareader and interreader agreement analysis was performed. STATISTICAL TESTS: McNemar test, Cohen's κ, and intraclass correlation coefficients. A P-value <0.05 was considered significant. RESULTS: 7 patients had positive findings on MRI and CT, 22 patients on joint reading with PET/CT, and 18 patients joint reading with PET/MRI. For overall positivity, interreader agreement was poor for MR and CT (κ = 0.36) and almost perfect with addition of PET (PET/CT κ = 0.85, PET/MRI κ = 0.85). The addition of PET from PET/CT and PET/MRI changed intended treatment in 20 and 18 patients, respectively. Between joint readings, intended treatment was different for eight patients. DATA CONCLUSION: The addition of [18F]PSMA-1007 PET/MRI or PET/CT to MRI and CT may increase detection rates, could reduce interreader variability, and may change intended treatment in half of patients with BCR. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 3.

123I Scan With Whole-Body Retention Measurement at 48 Hours for Simplified Dosimetry Before 131I Treatment of Metastatic Thyroid Cancer.

ABSTRACT: A previously published model (Atkins) allows for calculation of 131I maximum tolerated activity on the basis of 48-hour whole-body retention of 131I on a pretherapy diagnostic scan. Our practice uses iodine 123I for diagnostic imaging of metastatic thyroid cancer for staging before 131I therapy, with images typically acquired 24 hours after administration of the radiopharmaceutical. We explored the feasibility of an additional 123I whole-body scan and retention measurement at 48 hours, with application of the model to estimate maximum tolerated activity of radioiodine before 131I treatment of metastatic thyroid cancer.

18F-Fluciclovine PET/CT in Suspected Residual or Recurrent High-Grade Glioma.

PURPOSE: To retrospectively investigate the uptake of F-fluciclovine on PET/CT in patients with suspected recurrent high-grade glioma (HGG). METHODS: Twenty-one patients were included. The standard of truth was histopathologic interpretation if available. When histopathology was not available or rebiopsy did not show signs of malignancy, clinical follow-up including MRI and clinical outcome was considered the standard of truth. RESULTS: All 21 patients met the reference standard of either histopathologic proof of HGG recurrence (n = 10) or disease progression clinically and with tumor growth corresponding to the primary tumor sites on follow-up MRI (n = 11). Median time from PET/CT to death was 5 months (range, 1-20 months). Median time from primary diagnosis to death was 14.5 months (range, 6 to >400). Average SUVmax of the lesions was 8.3 ± 5.3 (SD) and 0.34 ± 0.13 for normal brain tissue. Median lesion-to-background ratio was 21.6 (range, 3.1-84.4). In 4 patients, F-fluciclovine PET/CT detected small satellite tumors that had not been reported on MR. CONCLUSIONS: The uptake of F-fluciclovine in clinically and/or histopathologically confirmed recurrent HGG is high compared with the uptake reported for other amino acid PET tracers. Because of the high tumor uptake and thus high tracer contrast, small satellite tumors with a diameter below usual reported PET spatial resolution and not reported on MRI were detected in 4 patients. As no patients with confirmed treatment-related changes were included, we cannot as of yet ascertain the ability of F-fluciclovine PET to discriminate between recurrent HGG and treatment-related changes, for example, pseudoprogression and radionecrosis.

Dose painting for re-irradiation of head and neck cancer.

BACKGROUND: For patients with recurrent or second primary disease, re-irradiation can be challenging due to overlap with previously irradiated volumes. Dose painting may be attractive for these patients, as the focus is on delivering maximal dose to areas of high tumor activity. Here, we compare dose painting by contours (DPBC) treatment plans based on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) with conventional plans. MATERIAL AND METHODS: We included 10 patients with recurrent or second primary head and neck cancer (HNC) eligible for re-irradiation. Our conventional re-irradiation regimen is hyperfractionated radiotherapy 1.5 Gy twice daily over 4 weeks, giving a total dose of 60 Gy. For DPBC, we defined two prescription volumes, PV33 and PV66, corresponding to 33 and 66% of the highest FDG uptake in the tumor. The clinical target volume (CTV) prescription dose was 60 Gy, PV33; 65-67 Gy and PV66; 70-73 Gy. The DPBC plan is to be given the first 20 fractions and the conventional plan the last 20 fractions. Dose to organs at risk (OARs) were compared for DPBC and conventional treatment. By summation of the initial curative plan and the re-irradiation plan, we also evaluated differences in dose to the 2 ccm hot spot (D2cc). RESULTS: We achieved DPBC plans with adequate target coverage for all 10 patients. There were no significant differences in OAR doses between the standard plans and the DPBC plans (p=.7). Summation of the initial curative plan and the re-irradiation plan showed that the median D2cc increased from 130 Gy (range 113-132 Gy; conventional) to 140 Gy (range 115-145 Gy; DPBC). CONCLUSIONS: Our proposed DPBC could be straightforwardly implemented and all plans met the objectives. Re-irradiation of HNC with DPBC may increase tumor control without more side effects compared to conventional radiotherapy.

Serum cytokine profiles and metabolic tumor burden in patients with non-small cell lung cancer undergoing palliative thoracic radiation therapy.

PURPOSE: Radiation therapy effectively kills cancer cells and elicits local effects in the irradiated tissue. The aim of this study was to investigate the kinetics of cytokines in the serum of patients with lung cancer undergoing radiation therapy and to identify associations with metabolic tumor burden as determined by 2-deoxy-2-fluoro-D-glucose (18F-FDG) positron emission tomography (PET). METHODS AND MATERIALS: Forty-five patients with advanced non-small cell lung cancer were included in a phase 2 clinical trial and randomized between fractionated thoracic radiation therapy alone or concurrent with an epidermal growth factor receptor inhibitor. Blood was sampled at 4 different time points: prior to treatment, midtherapy, at the end of therapy, and 6 to 8 weeks after the start of treatment. The serum concentrations of 48 cytokines and 9 matrix metalloproteinases were measured with multiplex immunoassays. A subset of patients was examined by 18F-FDG PET/computed tomography before, during, and after radiation therapy. The maximum standardized uptake values (SUVmax) of the primary lung tumor, whole-body metabolic tumor volume, and total lesion glycolysis were calculated, and correlations between the PET parameters and cytokines were investigated. RESULTS: The SUVmax decreased from baseline through midtherapy to posttherapy 18F-FDG PET/computed tomography (P = .018). The serum levels of C-C motif chemokine ligand (CCL) 23, CCL24, C-X3-C motif chemokine ligand 1, and interleukin-8 (C-X-C motif ligand [CXCL]8) were significantly correlated to SUVmax, metabolic tumor volume, and total lesion glycolysis before, during, and after radiation therapy. CXCL2 (P = .030) and CXCL6 (P = .010) decreased after the start of therapy and changed significantly across the sample time points. Serum concentrations of CCL15 (P = .031), CXCL2 (P = .028), and interleukin-6 (P = .007) were positively correlated to the irradiated volume during the second week of treatment. CONCLUSIONS: Cytokine serum levels vary and correlate with metabolic tumor burden in patients with advanced non-small cell lung cancer undergoing palliative thoracic radiation therapy.

FDG-based quantitative comparison of glucose metabolism in vitro, exemplified by a head-to-head comparison between a triple-negative breast cancer cell line and a non-malignant foetal cell line.

BACKGROUND: Glucose metabolism can be studied in vitro by a variety of means, also by fluorodeoxyglucose (FDG). As an example of the potential use we have compared the high glucose consumption in cancer cells and in transformed non-malignant foetal cells. The high glucose metabolism in cancer cells is not primarily for the production of energy, a large proportion is transformed to lactate only, producing two instead of potentially 32 ATP equivalents. The secreted lactate reduces the pH in the local microenvironment and gives malignant cells, more apt to thrive in hypoxic and acid environments, a competitive advantage. PURPOSE: To demonstrate the use of FDG in head-to-head comparison of glucose uptake and lactate production in a highly malignant and a highly proliferative non-malignant cell line. MATERIALS AND METHODS: Cell cultures of a foetal kidney cell line and a triple negative breast cancer cell line were incubated with FDG for one hour, washed, harvested and the radioactivity content in the cells was measured in a well counter. The lactate concentration was measured in conditioned medium. RESULTS: The FDG uptake was consistently higher in the non-malignant foetal cell line. The levels of lactate in the conditioned medium were similar. CONCLUSION: Quantitative comparison of glucose metabolism by in vitro use of FDG is a practical, cheap and rapid method. Some foetal cells have higher glucose uptake and produce as much lactate as this highly malignant cell line. This is an argument against the high glucose consumption being related solely to malignancy.

Cervical lymph node metastases of squamous cell carcinoma of unknown origin: the diagnostic value of FDG PET/CT and clinical outcome.

FDG PET/CT is perceived as a valuable diagnostic tool in addition to the standard diagnostic workup for patients with isolated neck lymph nodes of squamous cell carcinoma of unknown primary (SCCUP). For patients with SCCUP intended for primary radiotherapy, we hypothesize that the previously reported FDG PET/CT detection rates are too high. From 2008 to 2015, 30 SCCUP patients were examined with FDG PET/CT. The objective of the FDG PET/CT examination was twofold: (1) improve the radiotherapy target definition, and (2) identify the primary cancer. Before the FDG PET/CT, the patients had been through a standard workup consisting of CT of the neck and chest, examination with flexible endoscopy with patient awake, panendoscopy and examination under general anesthesia, tonsillectomy and sometimes blind sampling biopsies, and MRI (floor of the mouth). All FDG PET/CTs were performed applying a flat table, head support and fixation mask as part of the radiotherapy treatment planning. Diagnostic CT with contrast was an integrated part of the PET/CT examination. Only 1/30 patients (cancer of the vallecula) had their primary cancer detected by FDG PET/CT. In addition, a non-biopsied patient with high uptake in the ipsilateral palatine tonsil was included, giving a detection rate of ≤7 % (95 % CI 2-21 %). In this retrospective study, we found that the FDG PET/CT detection rate of the primary for SCCUP patients is lower than previously reported. It is questionable whether FDG PET/CT is necessary for these patients when improved, advanced workup is available.

Diffusion-weighted MRI compared to FDG PET/CT for assessment of early treatment response in lymphoma.

BACKGROUND: 18F fluoro-deoxyglucose (FDG) positron emission tomography / computed tomography (PET/CT) is a well-recognized diagnostic tool used for staging and monitoring of therapy response for lymphomas. During the past decade diffusion-weighted (DW) magnetic resonance imaging (MRI) is increasingly being included in the assessment of tumor response for various cancers. PURPOSE: To compare the change in maximum standardized uptake value (ΔSUVmax) from FDG PET/CT with the change in apparent diffusion coefficient (ΔADC) from DW MRI after initiation of the first cycle of chemotherapy in patients with Hodgkin's lymphoma (HL) and in patients with diffuse large B-cell lymphoma (DLBCL). MATERIAL AND METHODS: Twenty-seven consecutive patients with histologically proven lymphoma and lymphomatous lymph nodes (LLN) of the neck (19 with HL, 8 with DLBCL) underwent FDG PET/CT and MRI of the neck before and after initiation of the first cycle of chemotherapy. The mean time interval from initiation of chemotherapy to imaging was 19 days and 2 days for FDG PET/CT and MRI, respectively. For each patient ΔSUVmax, ΔADC, and change in volume of the same LLN were compared. RESULTS: There was a significant mean decrease of SUVmax by 70%, but no significant change in ADC. There was no significant reduction in LLN volume. CONCLUSION: There was no significant correlation between ΔSUVmax and ΔADC. Thus, our data do not support that FDG PET/CT can be replaced by early DW MRI for response evaluation in lymphoma patients.

Perceived misinterpretation rates in oncologic 18F-FDG PET/CT studies: a survey of referring physicians.

UNLABELLED: Because only pathologic examination can confirm the presence or absence of malignant disease in cancer patients, a certain rate of misinterpretation in any kind of imaging study is inevitable. For the accuracy of interpretation to be improved, determination of the nature, causes, and magnitude of this problem is needed. This study was designed to collect pertinent information from physicians referring patients for oncologic (18)F-FDG PET/CT. METHODS: A total of 662 referring physicians completed an 11-question survey focused on their experience with the interpretation of oncologic (18)F-FDG PET/CT studies. The participants were oncologists (36.1%; n = 239), hematologists (14.5%; n = 96), radiation oncologists (7.4%; n = 49), surgeons (33.8%; n = 224), and other physicians (8.2%; n = 54). Questions were aimed at determining the frequency, nature, and causes of scan misinterpretations as well as potential solutions to reduce the frequency of misinterpretations. RESULTS: Perceived misinterpretation rates ranged from 5% to 20%, according to most (59.3%) of the participants; 20.8% of respondents reported rates of less than 5%. Overinterpretation rather than underinterpretation was more frequently encountered (68.9% vs. 8.7%, respectively). Limited availability of a patient's history and limited experience of interpreters were the major contributors to this phenomenon, according to 46.8% and 26.7% of the participants, respectively. The actions most commonly suggested to reduce misinterpretation rates (multiple suggestions were possible) were the institution of multidisciplinary meetings (59.8%), the provision of adequate history when ordering an examination (37.4%), and a discussion with imaging specialists when receiving the results of the examination (38.4%). CONCLUSION: Overinterpretation rather than underinterpretation of oncologic (18)F-FDG PET/CT studies prevails in clinical practice, according to referring physicians. Closer collaboration of imaging specialists with referring physicians through more multidisciplinary meetings, improved communication, and targeted training of interpreting physicians are actions suggested to reduce the rates of misinterpretation of oncologic (18)F-FDG PET/CT studies.

Anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid: physiologic uptake patterns, incidental findings, and variants that may simulate disease.

UNLABELLED: Anti-1-amino-3-(18)F-fluorocyclobutane-1-carboxylic acid ((18)F-FACBC) is a synthetic amino acid analog PET radiotracer undergoing clinical trials for the evaluation of prostate and other cancers. We aimed to describe common physiologic uptake patterns, incidental findings, and variants in patients who had undergone (18)F-FACBC PET. METHODS: Sixteen clinical trials involving 611 (18)F-FACBC studies from 6 centers, which included dosimetry studies on 12 healthy volunteers, were reviewed. Qualitative observations of common physiologic patterns, incidental uptake, and variants that could simulate disease were recorded and compared with similar observations in studies of the healthy volunteers. Quantitative analysis of select data and review of prior published reports and observations were also made. RESULTS: The liver and pancreas demonstrated the most intense uptake. Moderate salivary and pituitary uptake and variable mild to moderate bowel activity were commonly visualized. Moderate bone marrow and mild muscle activity were present on early images, with marrow activity decreasing and muscle activity increasing with time. Brain and lungs demonstrated activity less than blood pool. Though (18)F-FACBC exhibited little renal excretion or bladder uptake during the clinically useful early imaging time window, mild to moderate activity might accumulate in the bladder and interfere with evaluation of adjacent prostate bed and seminal vesicles in 5%-10% of patients. Uptake might also occur from benign processes such as infection, inflammation, prostatic hyperplasia, and metabolically active benign bone lesions such as osteoid osteoma. CONCLUSION: Common physiologic uptake patterns were similar to those noted in healthy volunteers. The activity in organs followed the presence of amino acid transport and metabolism described with other amino acid-based PET radiotracers. As with other PET radiotracers such as (18)F-FDG, focal nonphysiologic uptake may represent incidental malignancy. Uptake due to benign etiologies distinct from physiologic background also occurred and could lead to misinterpretations if the reader is unaware of them.

Characterization of an asymmetric add-on collimator used with a hand-held gamma probe for radioguided surgery and sentinel node detection: a demonstration of an alternative collimation method.

OBJECTIVE: The aim of the study was to investigate a new principle for collimation of gamma probes for radioguided surgery and sentinel node detection: the use of asymmetric lateral shielding. The intension was to maintain the sensitivity in the lateral and forward directions on the unshielded side while at the same time to shield the probe against high activity sources that could mask the signal from the object to be detected. METHODS: The device was constructed to shield only against photons that come from a region in space that spans approximately 180° sideways and forwards relative to the detector. The intension of the study was to demonstrate the principle rather than to document its use in the clinic. Sensitivity profiles were derived from measurements obtained while stepwise moving the probe relatively to a point source of known activity surrounded by water. The measurements were taken in the symmetry plane of the collimator where the shielding effects were expected to be most pronounced. RESULTS: The asymmetric collimator led to nearly unchanged sensitivity in the lateral and forward directions. At the same time, the field of view was effectively shrunk on the shielded side. Contributions from sources lateral and close to the shield were reduced by factors up to 45. CONCLUSION: By rotating the probe around its longitudinal axis, an asymmetric add-on shield collimator could potentially make it easier to detect a sentinel node when this is located close to a neighbouring high activity region like the urinary bladder or the injection site.

A gel tumour phantom for assessment of the accuracy of manual and automatic delineation of gross tumour volume from FDG-PET/CT.

INTRODUCTION: Our primary aim was to make a phantom for PET that could mimic a highly irregular tumour and provide true tumour contours. The secondary aim was to use the phantom to assess the accuracy of different methods for delineation of tumour volume from the PET images. MATERIAL AND METHODS: An empty mould was produced on the basis of a contrast enhanced computed tomography (CT) study of a patient with a squamous cell carcinoma in the head and neck region. The mould was filled with a homogeneous fast-settling gel that contained both (18)F for positron emission tomography (PET) and an iodine contrast agent. This phantom (mould and gel) was scanned on a PET/CT scanner. A series of reference tumour contours were obtained from the CT images in the PET/CT. Tumour delineation based on the PET images was achieved manually, by isoSUV thresholding, and by a recently developed three-dimensional (3D) Difference of Gaussians algorithm (DoG). Average distances between the PET-derived and reference contours were assessed by a 3D distance transform. RESULTS: The manual, thresholding and DoG delineation methods resulted in volumes that were 146%, 86% and 100% of the reference volume, respectively, and average distance deviations from the reference surface were 1.57 mm, 1.48 mm and 1.0, mm, respectively. DISCUSSION: Manual drawing as well as isoSUV determination of tumour contours in geometrically irregular tumours may be unreliable. The DoG method may contribute to more correct delineation of the tumour. Although the present phantom had a homogeneous distribution of activity, it may also provide useful knowledge in the case of inhomogeneous activity distributions. CONCLUSION: The geometric irregular tumour phantom with its inherent reference contours was an important tool for testing of different delineation methods and for teaching delineation.

Extraosseous uptake with DPD (Teceos(®)).

OBJECTIVE: During a short period of 10 days, four patients presented with intense extraosseous uptake of a technetium-labelled bone-seeking agent, three in the heart and one in the liver at our hospital. During the next 6 weeks, identical heart uptake was found in another two patients. Two patients were re-examined, with identical uptake on the second occasion. A search for a possible cause was initiated. METHODS: Bone scintigraphy with Teceos(®) was performed after labelling the kit as described in the Summary of Product Characteristics [IBA, http://www.iba-molecular.com/sites/default/files/spcT1901E.pdf (in french, 29/3/2011)]. On two occasions, the kit used was retrospectively analysed, without any apparent abnormality. Two patients were re-examined 1 month later, with identical cardiac and liver uptake on repeat examination. Contact with referring physicians and blood test screening did not show any consistent reason for these extraosseous uptakes. Additionally, five cases at other hospitals in Norway have been brought to our attention. RESULTS: In at least ten patients, intense cardiac uptake has been recorded, all in relatively old patients, and one young patient had massive liver uptake. No abnormalities in labelling or composition of 3,3-diphospho-1,2-propanedicarboxylic acid were found. DISCUSSION: Liver and cardiac uptakes of bone-seeking agents have been described in amyloidosis, and for the heart, after myocardial infarction. We have ruled out any possible contamination by interfering radiopharmaceuticals and cannot find any reason for these findings. Eleven patients with amyloidosis seem one of several hypotheses that is highly improbable.

Synchronous and metachronous skeletal osteosarcomas: the Norwegian Radium Hospital experience.

Background. The purpose of this work was to study clinical and histopathological tumor characteristics of patients treated for synchronous or metachronous skeletal osteosarcoma at The Norwegian Radium Hospital from January 1, 1980 to January 1, 2008. Patients and methods. The hospital sarcoma database and patient records were reviewed to identify cases with synchronous or metachronous skeletal osteosarcoma. Patients with more than one skeletal lesion in the absence of pulmonary or other soft tissue tumor manifestations were included in the study, and histopathological slides from these tumors were reviewed. Results. Among a total of 297 registered osteosarcoma patients, six with synchronous (2.0%) and 10 with metachronous (3.4%) skeletal osteosarcomas were identified. All tumors were of high-grade malignancy. Treatment at the time of the first osteosarcoma diagnosis was in most cases wide resections and multi-agent chemotherapy according to international protocols, whereas the treatment for metachronous tumors was individualized and in general much less intensive. One patient was diagnosed with Li-Fraumeni syndrome, two other individuals may be suspected to have the same syndrome, and yet another patient had previously been treated for a bilateral retinoblastoma. Thirteen patients are dead, 11 from metastatic osteosarcoma, one from myelodysplastic syndrome, and one from wound infection and methotrexate-related nephrotoxicity; whereas three patients are still alive with no evidence of osteosarcoma. Conclusions. The prognosis for patients with synchronous and metachronous skeletal osteosarcoma is poor. However, because long-term survival is seen, aggressive treatment to selected cases, e.g., patients with an osteosarcoma predisposing syndrome and/or late occurring metachronous tumours, is justified. Revealing a possible clonal relationship between these tumors, e.g., by karyotyping, may be of interest for estimating prognosis and guide therapy intensiveness.

Integrin scintimammography using a dedicated breast imaging, solid-state gamma-camera and (99m)Tc-labelled NC100692.

OBJECTIVE: Integrin scintimammography with NC100692 and a dedicated gamma-camera, LumaGEM, based on semi-conductor technology, was performed to investigate the detection ability of this combination in breast cancer. METHODS: Eight patients with a high suspicion of breast cancer were administered 600-750 MBq (99m)Tc-labelled NC100629. Two acquisitions using a cranio-caudal and a lateral view were used, with moderate compression of the breast. RESULTS: LumaGEM scintigraphy revealed 9 of 11 malignancies, sized 6-20 mm. Two lesions in patients with multicentric disease were not diagnosed, one of which measured only 2.5 mm. In one patient, the procedure was inconclusive, due to major breast hypertrophy. CONCLUSION: The combined use of NC100629 and a dedicated gamma-camera for breast imaging was highly effective in diagnosing breast cancer.

Clinical significance of diffusely increased 18F-FDG uptake in the thyroid gland.

UNLABELLED: Our purpose was to determine the clinical significance of diffusely increased (18)F-FDG uptake in the thyroid gland as an incidental finding on PET/CT. METHODS: All patients who were found to have diffuse thyroid uptake on (18)F-FDG PET/CT in our institution between November 2004 and June 2006 were investigated and compared with an age- and sex-matched control group. The (18)F-FDG uptake in the thyroid was semiquantified using maximum standardized uptake value and correlated to the available serum thyroid-stimulating hormone (TSH) and thyroid peroxidase (TPO) antibody levels using regression analysis. RESULTS: Of the 4,732 patients, 138 (2.9%) had diffuse thyroid uptake. Clinical information was available for 133 of the 138 patients. Sixty-three (47.4%) had a prior diagnosis of hypothyroidism or autoimmune thyroiditis, of whom 56 were receiving thyroxine therapy. In the control group, consisting of 133 patients with no thyroid uptake, there were 13 (9.8%) with a prior diagnosis of hypothyroidism, 11 of whom were receiving thyroxine therapy. In the study group, 38 (28.6%) of 133 patients did not undergo any further investigation for thyroid disease, whereas 32 (24.1%) of 133 patients were examined for thyroid disease after PET. Nineteen were found with autoimmune thyroiditis or hypothyroidism, and replacement therapy was initiated in 12. No significant correlation was found between maximum standardized uptake value and TSH (P = 0.09) or TPO antibody (P = 0.68) levels. CONCLUSION: The incidental finding of increased (18)F-FDG uptake in the thyroid gland is associated with chronic lymphocytic (Hashimoto's) thyroiditis and does not seem to be affected by thyroid hormone therapy. SUV correlated neither with the degree of hypothyroidism nor with the titer of TPO antibodies.

The value of quantifying 18F-FDG uptake in thyroid nodules found incidentally on whole-body PET-CT.

OBJECTIVE: To determine if quantification of [18F]fluorodeoxyglucose (18F-FDG) uptake in a thyroid nodule found incidentally on whole-body 18F-FDG positron emission tomography-computed tomography (PET-CT) can be used to discriminate between malignant and benign aetiology. METHODS: A retrospective review of all patients with focally high uptake in the thyroid as an incidental finding on 18F-FDG PET-CT from May 2003 through May 2006. The uptake in the nodules was quantified using the maximum standardized uptake value (SUVmax). The aetiology was determined by cytology and/or ultrasound, or on histopathology. RESULTS: Incidental focally high uptake was found in 79/7347 patients (1.1%). In 31/48 patients with adequate follow-up, a benign aetiology was determined. Median SUVmax for the benign group was 5.6, range 2.5-53. Malignancy was confirmed in 15/48 patients. The malignancies were papillary thyroid carcinoma in 12, metastasis from squamous cell carcinoma in one, and lymphoma in two. Median SUVmax for the malignant lesions was 6.4, range 3.5-16. Cytology suspicious for follicular carcinoma was found in 2/48 patients. No statistical difference (P=0.12) was found among the SUVmax between the benign and malignant groups. CONCLUSION: Focally high uptake of 18F-FDG in the thyroid as an incidental finding occurred in 1.1% of the patients. Malignancy was confirmed or was suspicious in 17/48 (35%) of the patients that had adequate follow-up. There was no significant difference in the SUVmax between benign and malignant nodules.

Integrin receptor imaging of breast cancer: a proof-of-concept study to evaluate 99mTc-NC100692.

UNLABELLED: The present study was a proof-of-concept study to provide an initial indication of the efficacy and safety of imaging malignant breast tumors using (99m)Tc-NC100692. The agent is a small peptide with high affinity for integrin receptors that are upregulated and expressed preferentially on proliferating endothelial cells. METHODS: Sixteen patients with suggestive mammographic findings and 4 patients with benign lesions were included. The "standard of truth" was based on the histopathologic diagnosis of the recruited patients. All subjects received up to 75 microg of (99m)Tc-NC100692 with an average (99m)Tc activity of 694 MBq (range, 561-747 MBq). Safety endpoints were treatment-emergent adverse events (AEs) and changes in a limited physical examination, electrocardiogram (ECG) recordings, blood biochemistry, hematology, coagulation, vital signs, and urine analysis after administration of (99m)Tc-NC100692 and throughout the 24-h follow-up. Static images and SPECT were acquired between 40 min and 2.5 h after injection of the agent. Two experienced nuclear medicine physicians read the images in a nonblinded fashion. RESULTS: Nineteen of 22 malignant lesions were detected using (99m)Tc-NC100692 scintigraphy. Twenty lesions confirmed as malignant by histopathology were seen on mammography or ultrasound. Two additional lesions were identified from histopathology alone. Safety parameters evaluated through the follow-up period of 2.5 h included clinical laboratory tests, vital signs, and ECG. Five of 20 subjects experienced nonserious AEs, and all AEs were classified as mild. One subject experienced an AE (dysgeusia) possibly related to administration of (99m)Tc-NC100692. This AE was mild and lasted only for a few minutes. No deaths, serious AEs, or withdrawals due to AEs occurred during the study. CONCLUSION: Nineteen of 22 malignant lesions (86%) were clearly detected via scintigraphic imaging after administration of (99m)Tc-NC100692. Overall, the efficacy data in subjects with suspected breast lesions suggest that (99m)Tc-NC100692 scintigraphy may be effective in detecting malignant lesions. The use of (99m)Tc-NC100692 in subjects with breast cancer is safe and well tolerated. Further studies are warranted to assess the clinical potential of (99m)Tc-NC100692.