Long-term metabolic evolution of brain metastases with suspected radiation necrosis following stereotactic radiosurgery: longitudinal assessment by F-DOPA PET

BACKGROUND

The evolution of radiation necrosis (RN) varies depending on the combination of radionecrotic tissue and active tumor cells. In this study, we characterized the long-term metabolic evolution of RN by sequential PET/CT imaging with 3,4-dihydroxy-6-[18F]-fluoro-l-phenylalanine (F-DOPA) in patients with brain metastases following stereotactic radiosurgery (SRS).

METHODS

Thirty consecutive patients with 34 suspected radionecrotic brain metastases following SRS repeated F-DOPA PET/CT every 6 months or yearly in addition to standard MRI monitoring. Diagnoses of local progression (LP) or RN were confirmed histologically or by clinical follow-up. Semi-quantitative parameters of F-DOPA uptake were extracted at different time points, and their diagnostic performances were compared with those of corresponding contrast-enhanced MRI.

RESULTS

Ninety-nine F-DOPA PET scans were acquired over a median period of 18 (range: 12-66) months. Median follow-up from the baseline F-DOPA PET/CT was 48 (range 21-95) months. Overall, 24 (70.6%) and 10 (29.4%) lesions were classified as RN and LP, respectively. LP occurred after a median of 18 (range: 12-30) months from baseline PET. F-DOPA tumor-to-brain ratio (TBR) and relative standardized uptake value (rSUV) increased significantly over time in LP lesions, while remaining stable in RN lesions. The parameter showing the best diagnostic performance was rSUV (accuracy = 94.1% for the optimal threshold of 1.92). In contrast, variations of the longest tumor dimension measured on contrast-enhancing MRI did not distinguish between RN and LP.

CONCLUSION

F-DOPA PET has a high diagnostic accuracy for assessing the long-term evolution of brain metastases following SRS.

Intraoperative Gamma Probe Detection of Head and Neck Paragangliomas with 111In-Pentetreotide: A Pilot Study

Aims and background

The aim of this study was to assess whether intraoperative radiolocalization of head and neck paragangliomas with 111In-pentetreotide may increase surgical effectiveness, reducing the risk of recurrence.

Methods

Our study included eight patients with untreated, recently diagnosed paragangliomas (four unilateral and four bilateral tumors of the carotid body). After iv injection of −150 MBq 111In-pentetreotide, preoperative somatostatin receptor scintigraphy (SRS) was performed. SPECT of the neck was performed at four hours and planar Images of the head and neck were also obtained at four and 24 hours post injection. Scintigraphy was always compared with the results of conventional imaging methods (MRI, angiography and sonography). Intraoperative detection was performed on 11 lesions 24 hours after radiopharmaceutical administration using a handheld gamma probe.

Results

Preoperative SRS showed high radiotracer uptake in all patients. All the intraoperatively detected lesions were radically resected and histologically confirmed to be involved by tumor. No false positive results were recorded. Gamma probe detection revealed a small intracranial extension not detected by other imaging methods in a patient with a paraganglioma of the right carotid, and partial involvement of the carotid artery in another patient. During follow-up (median 3.5 years; range, 4 months-7 years) all patients remained disease free according to all parameters.

Conclusions

To our knowledge, this is the first experience of radioguided surgery in paraganglioma. Although our study included a relatively small number of patients, we suggest that intraoperative gamma probe detection may be a powerful tool to improve surgical effectiveness.

Hyperhomocysteinemia in acute iatrogenic hypothyroidism: the relevance of thyroid autoimmunity

PURPOSE

Hyperhomocysteinemia is a known cardiovascular risk factor and a key player in the inflammatory activation of autoimmune diseases. Hashimoto's thyroiditis (HT) is the leading cause of hypothyroidism which, in itself, has been associated with a significant raise of homocysteine (Hcy) levels and increased cardiovascular risk. Our aim was to assess the impact of HT on Hcy levels in patients with acute hypothyroidism.

METHODS

We prospectively enrolled 121 patients (mean age: 46 years, F/M = 102/19) with acute post-surgical hypothyroidism. Based on the presence of anti-thyroid antibodies and the histological description of an inflammatory infiltrate, 26 and 95 patients were classified as HT and non-HT, respectively. Several parameters including thyroid-stimulating hormone (TSH), levels of serum free T3 and free T4, weight, glucose levels, total cholesterol, creatinine, vitamin B₁₂, ferritin and erythrocyte sedimentation rate were obtained from all patients and correlated with Hcy levels.

RESULTS

Median Hcy level in the whole cohort was 16.8 µmol/L (normal values: < 12 µmol/l). Among all parameters analysed, only Hcy levels were significantly different between HT and non-HT patients (median Hcy = 19.7 vs 16.2 µmol/L, respectively; p = 0.018, Mann-Whitney U test). Analysis of covariance showed the presence of HT to be the strongest predictor of Hcy levels (coefficient = 0.25534, p = 0.001). Serum TSH was not significantly associated with Hcy levels (p = 0.943).

CONCLUSION

In patients with iatrogenic hypothyroidism, those with HT have significantly higher Hcy levels than those without HT. The increase of Hcy levels appears to be mainly determined by the HT-related immune-inflammatory condition.

Clinical Use of an Imaging Probe in Breast Cancer Surgery

Aim

Portable cameras allow easy transfer of the detector, and thus of radioisotope imaging, to the operating room. In this paper we describe our preliminary experience in radionuclide imaging of breast cancer with a 22.8 × 22.8 mm2 field-of-view minicamera called “Imaging Probe” (IP).

Methods

Breast cancer detection by IP was performed to guide biopsy, in particular open biopsy, or help fine-needle or core-needle positioning when the main guidance method was ultrasonography or digital radiography. 99mTc Sestamibi (MIBI) was injected 1 h before imaging and biopsy to 14 patients with suspected or known breast cancer. Scintigraphic images were acquired before and after biopsy in each patient. The surgeon was allowed to take into account scintigraphic images as well as previously performed mammograms and ultrasonography.

Results

High-resolution IP images were able to guide biopsy toward cancer or toward washout zones of cancer, which are thought to be chemoresistant, in seven patients out of 10. Four patients in whom IP and MIBI were unable to guide biopsy were found not to have cancer.

Conclusions

Our study confirms the ability of IP to guide breast biopsy even when our minicamera has to be handled manually by trained physicians during surgery.

Phase I Trial of Technetium [Leu13] Bombesin as Cancer Seeking Agent: Possible Scintigraphic Guide for Surgery?

Aims and Background

Bombesin-like neuropeptides work as neurotransmitters and growth factors at the same time. Several human cancers show overexpression of three receptors for mammalian counterparts of amphibian bombesins (ABNs), ie gastrin-releasing peptide (GRP), neuromedin B (NMB) and possibly another peptide. ABNs in turn are able to bind to mammalian and human receptors in vitro, and it is therefore interesting to study radioisotope-labeled bombesin (BN) and BN-like peptides as cancer seeking agents.

Methods and Study Design

Starting from the amino acid sequence of [Leu13] ABN, the Demokritos Institute has synthesized and labeled with technetium a new BN-like peptide that has the same biological characteristics as the amphibian peptide; changes were made only in the N-terminal part of this tetradecapeptide. After having obtained satisfactory results with 99mTc BN in a preclinical study, we started a phase I trial involving cancer patients as well as normal volunteers in Tomsk. Three normal volunteers, one patient with small cell lung cancer and one patient with primary prostate cancer were studied after iv injection of 185 MBq, corresponding to 0.7 micrograms of 99mTc BN. Dynamic images of the tumors were acquired for 20 mins, followed by SPET. Total body images were acquired in patients and normal volunteers 1 and 3 h after 99mTc BN acquisition. In addition, 99mTc sestamibi scintigraphy was performed in the patient with small cell lung carcinoma.

Results

No relevant side effects were observed. Both tumors were well visualized on early 1-2 mins images with planar as well as tomographic imaging. Total body images showed radioactivity in the liver, kidneys and thyroid gland. The stomach and spleen were never imaged. Radioactivity was found in the urinary bladder 4 mins after injection in the patient with prostate cancer. Three-hour total body scans showed radioactivity in the duodenum. In the patient in whom also 99mTc sestamibi scintigraphy was performed, thyroid uptake was much higher with sestamibi than with 99mTc BN, whereas the uptake of small cell lung carcinoma was higher with 99mTc BN than with sestamibi.

Conclusions

99mTc BN is able to clearly image tumors with BN receptor overexpression. Our first impression is that in the future this radiopharmaceutical may serve as a cancer seeking agent and, due to its high tumoral uptake, also as a radiotracer for radioisotope-guided surgery.

Radioguided Biopsy of Osteoid Osteoma: Usefulness of Imaging Probe

Aims and Background

When removal of osteoid osteoma is performed with open biopsy, the surgeon can be guided by radioactivity of 99mTc-MDP (methylene D- phosphonate) acquired by a probe.

Material and methods

We compared the performance of a commercially available ZnCdTe probe (Neoprobe 2000) and a one-square-inch-field-of-view imaging probe (IP) on two patients undergoing open biopsy for osteoid osteoma. Triphasic bone scintigraphy was performed before operation and Neoprobe as well as IP were used in the operating room by two nuclear physicians. When the surgeon asked for guidance, each nuclear physician had to indicate a precise direction.

Results

The surgeon asked for guidance once in the first operation, on a patient with osteoid osteoma of the femur, and four times in the second operation, for osteoid osteoma of the acetabulum. The indications provided by IP were correct 5/5 times, whereas the commercial probe was correct 3/5 times. Both devices were able to assess the surgical radicality. After biopsy, bone samples were divided into high-count and low-count samples. Pathological examination confirmed the presence of osteoid osteoma in high-count samples.

Conclusions

IP has already been used to guide biopsy, but only in breast disease. The present work confirms its good performance also in orthopedics as a portable mini gamma camera that can be used in the operating room.

New Localization Technique for Breast Cancer Biopsy: Mammotome Guidance with Imaging Probe

Aims and Background

The “Imaging probe” (IP) is a small, portable, high-resolution gamma camera to be used in radioguided surgery. The present work discusses a special prototype designed for guiding biopsies. The IP was mounted to a Fischer digital X-ray stereotactic core biopsy system in such a way that biopsy could be guided simultaneously by X-ray stereotaxis and 99mTc-Sestamibi (MIBI) images from IP.

Methods

The IP field of view was 22.8 × 22.8 mm2, with a spatial resolution of approx. 2.5 mm. We used off-line software for image fusion on a dedicated Pentium III portable PC. It was matched with a Fischer digital X-ray stereotactic biopsy system dedicated to direct the mammotome towards breast opacities. The operator was allowed to slightly correct the direction of the mammotome needle taking into account stereotactic X-ray, scintigraphic and fused images. Biopsy samples were counted by IP before they were sent to the pathologist.

Results

High-resolution IP scintigraphy showed substantial, though not exact, matching between MIBI hot spots and X-ray opacities. More than one hot spot was detected even in the smallest (0.6 cm) lesion. Post-biopsy scintigraphy showed absence of significant hot spots in two patients, whereas in the third patient one of the three hot spots was still partially present. All lesions showed cancer on histological examination.

Conclusions

Measurement of radioactivity in biopsy specimens confirmed the heterogeneous distribution of radioactivity within cancers that IP had detected before biopsy.

Intraoperative Sentinel Node Detection by an Innovative Imaging Probe

Intraoperative tumor detection has been used in many applications, and today the sentinel node technique is a widely employed surgical procedure in breast cancer. Different detector systems are employed but several problems have been reported in clinical practice, in particular the difficulty to accurately detect the sentinel node within the axillary soft tissue. The problem is even greater for abdominal and thoracic tumors. We propose an innovative Imaging Probe (IP) able to visualize on a monitor the primary tumor and secondary lesions, if appropriately radiolabeled. The IP can be optimally applied for minimally invasive surgery in breast cancer treatment, and a preliminary experience related to 15 patients and 20 sentinel nodes is reported here. We compared the results obtained with the IP to those obtained with an Anger camera and a traditional scintillation detector, and found them to be very promising. In particular the surgeon's work is greatly facilitated by direct visual guidance instead of a generic acoustic signal.

Breast Cancer Takes up 99mTc Bombesin. A Preliminary Report

Background

Several tumors including lung, prostate, ovarian, colon, and exocrine pancreatic cancer show receptors for the amphibian neurotransmitter and growth factor bombesin (BN) and its mammalian counterparts gastrin-releasing peptide and neuromedin B. Also breast cancer has been reported to show such receptors: the presence of BN receptors in primary breast cancer has been demonstrated on cultured cells and by autoradiography on breast tissue samples. Authors who have studied BN receptors in breast cancer do not agree on their frequency in primary cancer, but indicate that 100% of metastatic breast cancers show such receptors.

Methods

We examined three primary breast cancer patients with 99mTc BN and 99mTc sestamibi one week before surgery. One of them showed axillary node invasion. The same acquisition technique was used for breast and chest imaging with both radiopharmaceuticals, whereas total body images were acquired only with 99mTc BN. Also the administered radioactivity was different: 20 mCi of 99mTc sestamibi and 5-8 mCi of 99mTc BN. Dynamic images were acquired for 20 mins after iv injection with the patient in ventral decubitus and the gamma camera positioned in lateral view, as is generally done in Khakhali's prone scintimammography. Anterior chest images were acquired for 30 mins. Prone scintimammography was performed one hour after administration of both tracers. ROIs were drawn on tumors and surrounding breast with the same technique in order to calculate the tumor to breast ratio (T/B). In addition, total body scan was performed one hour and three hours after 99mTc BN administration. All three patients underwent breast conserving surgery with lymphadenectomy. Postoperative pathologic assessment showed the following T and N stages in the three patients: T1bN0, T1cN0. and T1cN1.

Results

All three cancers were imaged with both tracers. The T/B of 99mTc BN was always higher than that of 99mTc sestamibi. Chest uptake was always much higher with 99mTc sestamibi than with 99mTc BN. Comparison between 99mTc BN and 99mTc sestamibi images gave other intriguing results: in the N1 patient both tracers clearly imaged the invaded node, but on the 99mTc BN image the primary tumor was larger than on the 99mTc sestamibi image and the node was smaller. It is known that 99mTc BN is not taken up by vessels and inflammatory tissue. The time activity curves of the two tracers were significantly different in all patients, with an increase in 99mTc BN uptake in the first three to five minutes, followed by a less sharp uprise of the curve, quite similar to a plateau.

Conclusions

Our first impression is that 99mTc BN is a useful breast cancer seeking agent and very promising for lymph node staging.

Sentinel Node Detection with Imaging Probe

A one-square-inch-field-of-view mini gamma camera, whose first prototype was built by us in 1998 and given the name imaging probe (IP), was initially employed in sentinel lymph node (SLN) detection. This is probably the best way of learning how to use it. In the present work IP was used for SLN localization by a medical team that, after having been trained by the group of nuclear physicians of “La Sapienza” University who designed and first used the detector, used IP at their own hospital to 1) acquire experience for future use during surgery (a cooperative project on IP-radioguided orthopedic surgery is ongoing) and 2) start multicenter trials with IP. The SLN was identified and localized with IP and a non-imaging probe, Neoprobe 2000, in six patients with breast cancer who underwent lymphoscintigraphy for SLN biopsy. The operators who used Neoprobe and IP were blinded to each other's findings and to the results obtained with the large-field-of-view Anger camera that was used for lymphoscintigraphy. The Anger camera, IP and Neoprobe detected seven SLNs in six patients. The mean detection time was 2 mins 6 s (standard deviation (SD) 26 s) with IP, and 2 mins 18 s (SD 47 s) with Neoprobe 2000. The SLN that was most difficult to find was detected in 2 mins 56 s with IP and 3 mins 45 s with Neoprobe. The operators' subjective impression of having detected the SLN was “absolutely sure” for 7/7 nodes with IP and “absolutely sure” for 5/7 nodes with Neoprobe.

A Study of Sentinel Node Biopsy in T1 Breast Cancer Treatment: Experience of 48 Cases

Axillary clearance in breast cancer has been proven to be unnecessary in more than 50% of cases. Sentinel node biopsy (SNB) is a new technique that can be used to avoid unneccesary axillary clearance in breast cancer surgery. Our integrated team, consisting of surgeons, pathologists and nuclear medicine physicians, studied 48 cases of T1 breast cancer with lymphoscintigraphy-guided SNB. Before starting this study, the team performed 20 SNBs as a learning procedure. 500 μCi of 99mTc-nanocoll in 0.2 mL were injected around the lesion, under US or x-ray guidance if necessary. Static images in anterior, lateral and lateral oblique view collected at the end of a 20 min dynamic study were used to mark the SN on the skin. During surgery a gamma probe was used to guide SN resection, and node invasion was assessed with cytokeratin immunohistochemistry. In 14 patients tracer uptake was observed in a single node, in 30 patients in 2–4 nodes, whereas in four patients the nodes were scintigraphically missed. Surgical resection was possible in 42 nodes out of 54. All but two patients with negative immunohistochemistry for cancer cell clusters showed metastasis-free axillary nodes. All patients with positive SNBs (13) showed involved axilla. In four patients the lymphatic drainage was towards the intramammary chain; one node was juxtaclavicular and one node was intramammary in the upper outer quadrant. The overall sensitivity of the method was about 80%, the specificity about 90% with a diagnostic accuracy about 80%. SNB is a promising method for surgical decision-making regarding axillary clearance in breast cancer. Adequate training of an interdisciplinary team is needed in order to successfully perform SNB and assess SN invasion. Its unusual anatomic location can be encountered and technical care is necessary to correctly identify and remove them.

Detection of Sentinel Node in Breast Cancer: Pilot Study with the Imaging Probe

The commonly used gamma probes are easy to use but also give rough information when employed in radioisotope-guided surgery. When images are required for exact localization, a gamma camera as well as a probe have to be used. Position-sensitive photomultipliers have contemporaneously allowed high-resolution scintigraphy and miniaturization of gamma cameras. We have assembled a miniature gamma camera with a 1-square-inch field of view and an intrinsic resolution of about 1 mm. When the minicamera is collimated with a large-holed, highly sensitive collimator, it acquires a spatial resolution of 3 mm. This prototype has been tested in the detection of difficult-to-image breast cancer sentinel nodes. Five nodes that had not been found with the usual technique of an Anger camera plus conventional probe were checked with the miniature camera that we named imaging probe: it actually is small enough to be used as a probe and large enough to give an image. One of the five nodes was found and imaged. It was small, disease-free, close to the tumor and probably hidden by the Compton halo around the peritumoral injection site. Our pilot study shows that the imaging probe, although still a prototype, has certain advantages over conventional methods when lymph node localization is required during surgery.

Non-Sentinel Lymph Node Metastases in Breast Cancer Patients with a Positive Sentinel Lymph Node: Validation of Five Nomograms and Development of a New Predictive Model

Aims and Background

Discordance of intraoperative analysis with definitive histology of the sentinel lymph node in breast cancer leads to completion axillary lymph node dissection, which only in 35–50% shows additional nodal metastases. The aim of the study was to identify individual patient risk for non-sentinel lymph node metastases by validating several statistical methods present in the recent literature and by developing a new tool with the final goal of avoiding unnecessary completion axillary lymph node dissection.

Methods

We retrospectively evaluated 593 primary breast cancer patients. Completion axillary lymph node dissection was performed in 139 with a positive sentinel lymph node. The predictive accuracy of five published nomograms (MSKCC, Tenon, Cambridge, Stanford and Gur) was measured by the area under the receiver operating characteristic curve. We then developed a new logistic regression model to compare performance. Our model was validated by the leave-one-out cross-validation method.

Results

In 53 cases (38%), we found at least one metastatic non-sentinel lymph node. All the selected nomograms showed values greater than the 0.70 threshold, and our model reported a value of 0.77 (confidence interval = 0.69–0.86 and error rate = 0.28) and 0.72 (confidence interval = 0.63–0.81, error rate = 0.28) after the validation. With a 5% cutoff value, sensitivity was 98% and specificity 9%, for a cutoff of 10%, 96% and 2%, respectively.

Conclusions

All the nomograms were good discriminators, but the alternative developed model showed the best predictive accuracy in this Italian breast cancer sample. We still confirm that these models, very accurate in the institution of origin, require a new validation if used on other populations of patients.

Is Complete Axillary Dissection Necessary for all Patients with Positive Findings on Sentinel Lymph Node Biopsy? Validation of a Breast Cancer Nomogram for Predicting the Likelihood of a Non-Sentinel Lymph Node

Aim and background

Axillary dissection in patients positive for sentinel lymph nodes is currently under discussion in the literature, since approximately only 50% of such patients has metastases in the remaining lymph nodes. To identify patients at risk for non-sentinel lymph nodes metastases, a nomogram was developed by the Breast Service of the Memorial Sloan-Kettering Cancer Center. The aim of this study was to assess the nomogram's predictive accuracy in a population of Italian breast cancer patients in our hospital.

Materials and methods

The system of calculation used as variables prognostic factors of breast cancer: pathologic size, tumor type and nuclear grade, lymphovascular invasion, multifocality, estrogen receptor status, method of detection of the sentinel lymph nodes metastases (frozen section, serial hematoxylin-eosin, routine hematoxylin-eosin, and immunohistochemistry), number of positive and number of negative sentinel lymph nodes.

Results and conclusions

To measure the discrimination of the nomogram, a receiver-operating characteristic curve was construed, and the area under the curve was calculated. However, the area under the curve was 0.72, a very high value considering that the limit of acceptability is 0.70–0.80. The calculation system developed by the Memorial Sloan-Kettering Cancer Center provides a predictive value on the histopathologic state of sentinel lymph nodes.

18F-DOPA uptake parameters in glioma: effects of patients' characteristics and prior treatment history

OBJECTIVE

In amino acid positron emission tomography brain tumour imaging, tumour-to-background uptake parameters are often used for treatment monitoring. We studied the effects of patients' characteristics and anticancer treatments on ¹⁸F-fluoro-l-phenylalanine uptake of normal brain and tumour lesions, with particular emphasis on temozolomide (TMZ) chemotherapy.

METHODS

155 studies from 120 patients with glioma were analysed. Average uptake of normal background (standardized uptake value, SUVbckgr) and basal ganglia (SUVbg), as well as tumour-to-brain ratios (TBR) were compared between positron emission tomography/CT studies acquired before (Group A, n = 48), after (Group B, n = 50) or during (Group C, n = 57) TMZ treatment, using analysis of variance.

RESULTS

Overall, mean SUVbckgr and mean SUVbg were 1.06 ± 0.26 and 2.12 ± 0.47, respectively. Female had significantly higher SUVbckgr (p = 0.002) and SUVbg (p = 0.012) than male patients. Age showed a positive correlation with SUVbg (p = 0.001). In the overall cohort, there were significant effects of TMZ on SUVbckgr (p = 0.0237) and TBR (p = 0.0138). In particular, SUVbckgr was lower in Group C than in Group B (1.00 ± 0.25 vs 1.14 ± 0.31, p = 0.0173). Significant variations of SUVbckr could be observed in female only. TBR was significantly higher in Group C than in Group B (2.37 ± 0.54 vs 2.06 ± 0.38, p = 0.010). Variations of SUVbg between groups slightly missed significance (p = 0.0504).

CONCLUSION

Temozolomide chemotherapy and patients' characteristics, including gender and age, affect physiological [¹⁸F]-fluoro-l-phenylalanine uptake and, consequently, the calculation of TBRs. Advances in knowledge: For the first time, the effects of past or concurrent temozolomide chemotherapy on brain physiological amino acid uptake have been investigated. Such effects are relevant and should be taken into account when evaluating tumour-to-background ratios.

Clinical Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography in the Diagnostic Algorithm of Advanced Entero-Pancreatic Neuroendocrine Neoplasms

BACKGROUND

The role of ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in the diagnostic algorithm of entero-pancreatic neuroendocrine neoplasms (EP NENs) is unclear because most available data derive from heterogeneous populations in terms of tumor biology and disease status at time of examination. The aim of this study was to determine the ability of ¹⁸F-FDG PET to identify patients with more aggressive disease among those with advanced EP NENs. Subjects, Materials, and Methods . Patients with advanced EP NENs and known disease status (progressive disease [PD] or stable disease [SD]) according to imaging procedures, who received ¹⁸F-FDG PET and computed tomography scans during a time frame of 1 month, were included.

RESULTS

A total of 93 patients, including 69 patients with pancreatic NENs and 24 patients with small-intestine NENs, were included. At the time of study entry, 64 patients (68.8%) had PD, and the remaining 29 patients (31.2%) had SD. A total of 62 patients (66.7%) had positive ¹⁸F-FDG PET, whereas ¹⁸F-FDG PET was negative in the remaining 31 patients (33.3%). Overall, ¹⁸F-FDG PET sensitivity and specificity to detect PD were 90.6% and 86.2%, respectively, resulting in a diagnostic accuracy of 89.2%. A positive ¹⁸F-FDG PET was significantly associated with PD at the time of study entry (p < .0001 at multivariate analysis). Although a higher proportion of ¹⁸F-FDG PET-positive examinations were observed in patients with higher tumor grade (p = .01), 53.8% of patients with grade 1 neuroendocrine tumors (NETs) had positive ¹⁸F-FDG PET, and 37.5% of patients with grade 2 NETs had negative ¹⁸F-FDG PET. Overall survival was significantly shorter in ¹⁸F-FDG PET-positive patients (median: 60 months) in comparison with ¹⁸F-FDG PET-negative patients (median not reached; p = .008).

CONCLUSION

¹⁸F-FDG PET has a high diagnostic accuracy to identify progression of disease with unfavorable clinical outcome in patients with advanced EP NENs. Knowledge of disease status and G grading are key factors for physicians to better select patients for whom ¹⁸F-FDG PET is clinically useful.

IMPLICATIONS FOR PRACTICE

The findings of the present study may help physicians dealing with advanced neuroendocrine neoplasms to select patients for whom ¹⁸F-fluorodeoxyglucose positron emission tomography is useful to predict poor clinical outcome.

Cardiac Radionuclide Imaging in Rodents: A Review of Methods, Results, and Factors at Play

The interest around small-animal cardiac radionuclide imaging is growing as rodent models can be manipulated to allow the simulation of human diseases. In addition to new radiopharmaceuticals testing, often researchers apply well-established probes to animal models, to follow the evolution of the target disease. This reverse translation of standard radiopharmaceuticals to rodent models is complicated by technical shortcomings and by obvious differences between human and rodent cardiac physiology. In addition, radionuclide studies involving small animals are affected by several extrinsic variables, such as the choice of anesthetic. In this paper, we review the major cardiac features that can be studied with classical single-photon and positron-emitting radiopharmaceuticals, namely, cardiac function, perfusion and metabolism, as well as the results and pitfalls of small-animal radionuclide imaging techniques. In addition, we provide a concise guide to the understanding of the most frequently used anesthetics such as ketamine/xylazine, isoflurane, and pentobarbital. We address in particular their mechanisms of action and the potential effects on radionuclide imaging. Indeed, cardiac function, perfusion, and metabolism can all be significantly affected by varying anesthetics and animal handling conditions.

Diagnosis and follow-up of idiopathic retroperitoneal fibrosis: role of (18)F-FDG-PET/CT and biochemical parameters in patients with renal involvement

Idiopathic retroperitoneal fibrosis (IRF) is a rare disease characterized by fibro-inflammatory reaction surrounding ureters and other inner organs with possible secondary renal involvement. Symptoms are aspecific and recurrent phases of activity are generally associated with elevation of inflammatory indices. 18F-FDG-PET is nowadays an important tool for the detection of this disease, allowing differentiation between metabolically active tissue and fibrotic one. The purpose of this study was to investigate the role of 18F-FDG-PET in the management of IRF and to evaluate possible correlations between biochemical parameters and PET/CT findings of disease activity. We enrolled seven consecutive patients with IRF (in five histology proved the disease) observed from 2003 to 2012 (5 M:2 F, mean age 53.8 years, range 44-86 years). All patients presented with fever as first symptom; two had obstructive renal failure requiring hemodialysis; one underwent monolateral nephrectomy for parenchyma infiltration; six presented ureteral involvement; three underwent ureteral stent placement. For each patient, during a mean total follow-up of 26.5 months we evaluated serum creatinine, BUN, Hb, RBCs, WBCs, PLT, CRP, ESR. Periodic 18F-FDG-PET/CT scans (every 5.9 months-mean) were performed in all patients. Statistical evaluation was performed using "stepwise regression" analysis. Steroids and immunosuppressive agents induced a progressive normalization of PET/CT scans in all patients at the end of follow-up. Stepwise regression analysis showed that BUN, serum creatinine and CRP only if considered together, significantly correlated with SUV max (p value = 0.000003057). 18F-FDG-PET is a useful tool for clinical decision making in patient with IRF, allowing to evaluate the efficacy of the pharmacological treatment and to detect early recurrences, to modify the therapeutic approach. Acute phase reactants are not reliable alone for the management and the follow-up as they are often not concordant with metabolic assessment of the disease. In patients with ureteral involvement, CRP together with BUN and serum creatinine has a significant correlation with PET/CT results, and can help physicians in therapeutic approach, better than a single parameter.

Thyro-gastric autoimmunity in patients with differentiated thyroid cancer: a prospective study

Thyro-gastric autoimmunity has not been previously evaluated in patients with differentiated thyroid cancer (DTC), although its long-term complications may be relevant for the management of DTC patients. We assessed the prevalence of gastric autoimmunity and autoimmune gastritis (AG) in patients with Hashimoto's thyroiditis (HT) and concomitant DTC. Prevalence of parietal cell antibody (PCA) positivity, iron deficiency anemia (IDA), and pernicious anemia (PA) were prospectively assessed in 150 DTC patients referred for radioiodine ablation after total thyroidectomy. Patients were classified as HT (n = 31) and non-HT (n = 119) based on a combination of serological, ultrasonographic, and histological findings. Patients with PCA positivity were subsequently addressed to endoscopy for confirmation of atrophy body gastritis, required for the diagnosis of AG. For all the variables under study, a comparison between groups was made using Fisher's exact test and appropriate parametric and non-parametric tests. PCA positivity was significantly more prevalent in HT than in non-HT patients (12.9 vs 1.6 %, p = 0.017). After Hp eradication, a reversal of PCA positivity was observed in 3/4 patients in the HT group. IDA and PA did not differ significantly between groups. In the HT group, only one patient had endoscopical confirmation of mild gastric corporal atrophy. Gastric autoimmunity shows higher prevalence in patients with DTC and concomitant HT than in patients with DTC alone; however, in most cases, PCA positivity was associated with Hp infection. Furthermore, although previous reports found up to one-third of patients with HT to have associated AG, in our cohort AG was extremely rare.

Volumetric assessment of recurrent or progressive gliomas: comparison between F-DOPA PET and perfusion-weighted MRI

PURPOSE

To compare the diagnostic information obtained with 6-[(18)F]-fluoro-L-3,4-dihydroxyphenylalanine (F-DOPA) PET and relative cerebral blood volume (rCBV) maps in recurrent or progressive glioma.

METHODS

All patients with recurrent or progressive glioma referred for F-DOPA imaging at our institution between May 2010 and May 2014 were retrospectively included, provided that macroscopic disease was visible on conventional MRI images and that rCBV maps were available for comparison. The final analysis included 50 paired studies (44 patients). After image registration, automatic tumour segmentation of both sets of images was performed using the average signal in a large reference VOI including grey and white matter multiplied by 1.6. Tumour volumes identified by both modalities were compared and their spatial congruence calculated. The distances between F-DOPA uptake and rCBV hot spots, tumour-to-brain ratios (TBRs) and normalized histograms were also computed.

RESULTS

On visual inspection, 49 of the 50 F-DOPA and 45 of the 50 rCBV studies were classified as positive. The tumour volume delineated using F-DOPA (F-DOPAvol 1.6) greatly exceeded that of rCBV maps (rCBVvol 1.6). The median F-DOPAvol 1.6 and rCBVvol 1.6 were 11.44 ml (range 0 - 220.95 ml) and 1.04 ml (range 0 - 26.30 ml), respectively (p < 0.00001). Overall, the median overlapping volume was 0.27 ml, resulting in a spatial congruence of 1.38 % (range 0 - 39.22 %). The mean hot spot distance was 27.17 mm (±16.92 mm). F-DOPA uptake TBR was significantly higher than rCBV TBR (1.76 ± 0.60 vs. 1.15 ± 0.52, respectively; p < 0.0001). The histogram analysis showed that F-DOPA provided better separation of tumour from background. In 6 of the 50 studies (12 %), however, physiological uptake in the striatum interfered with tumour delineation.

CONCLUSION

The information provided by F-DOPA PET and rCBV maps are substantially different. Image interpretation is easier and a larger tumour extent is identified on F-DOPA PET images than on rCBV maps. The clinical impact of such differences needs to be explored in future studies.

Tumor thrombus in the renal vein from an adrenal metastasis of lung cancer: 18FDG PET/CT findings

Tumor thrombus is a rare complication of solid cancer. The authors report a case of a 76-year-old woman presenting a thick walled cystic mass in the lower lobe of the left lung. 18FDG positron emission tomography (PET)/computed tomography (CT) was performed, showing tracer accumulation in the wall of the pulmonary lesion and in the mediastinal and hilar lymph nodes. Moreover, PET/CT depicted a gross mass in the left adrenal gland and a hypermetabolic focus corresponding to the anatomic location of the left renal vein. Contrast-enhanced CT, subsequently performed, confirmed PET findings in the lung, lymph nodes, and adrenal glands, also demonstrating marginal enhancement and intraluminal filling defect in the left renal vein, which was interpreted as tumor thrombus due to the 18FDG uptake at PET scan. CT-guided biopsy of the mass was positive for poorly differentiated carcinoma. 18FDG PET can be useful to diagnose tumor thrombus in oncological patients.

(18)F-FDG PET/CT imaging of massive portal vein tumor thrombosis from ileal adenocarcinoma

A 72 years old patient was referred to us with ileal adenocarcinoma after surgical desection. Fluorine-18- fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) imaging showed massive portal vein, tumor thrombosis. Clinical examination and laboratory tests did not support the diagnosis of septic thrombus. To the best of our knowledge, this is the first reported case in the literature of a massive tumor thrombus in the right portal system from ileal carcinoma, detected by (18)F-FDG PET/CT.

(99m)Tc-labeled rituximab for imaging B lymphocyte infiltration in inflammatory autoimmune disease patients

Purpose

The rationale of the present study was to radiolabel rituximab with 99m-technetium and to image B lymphocytes infiltration in the affected tissues of patients with chronic inflammatory autoimmune diseases, in particular, the candidates to be treated with unlabelled rituximab, in order to provide a rationale for ‘evidence-based’ therapy.

Procedures

Rituximab was labelled with ^99mTc via 2-ME reduction method. In vitro quality controls of ^99mTc-rituximab included stability assay, cysteine challenge, SDS-PAGE, immunoreactive fraction assay and competitive binding assay on CD20+ve Burkitt lymphoma-derived cells. For the human pilot study, 350–370 MBq (100 μg) of ^99mTc-rituximab were injected in 20 patients with different chronic inflammatory autoimmune diseases. Whole body anteroposterior planar scintigraphic images were acquired 6 and 20 h p.i.

Results

Rituximab was labelled to a high labelling efficiency (>98%) and specific activity (3515–3700 MBq/mg) with retained biochemical integrity, stability and biological activity. Scintigraphy with ^99mTc-rituximab in patients showed a rapid and persistent spleen uptake, and the kidney appeared to be a prominent source for the excretion of radioactivity. Inflamed joints showed a variable degree of uptake at 6 h p.i. in patients with rheumatoid arthritis indicating patient variability; similarly, the salivary and lacrimal glands showed variable uptake in patients with Sjögren’s syndrome, Behçet’s disease and sarcoidosis. Inflammatory disease with particular characteristics showed specific uptake in inflammatory lesions, such as, dermatopolymyositis patients showed moderate to high skin uptake, a sarcoidosis patient showed moderate lung uptake, a Behçet’s disease patient showed high oral mucosa uptake and a polychondritis patient showed moderate uptake in neck cartilages. In one patient with systemic lupus erythematosus, we did not find any non-physiological uptake.

Conclusion

Rituximab can be efficiently labelled with ^99mTc with high labelling efficiency. The results suggest that this technique might be used to assess B lymphocyte infiltration in affected organs in patients with autoimmune diseases; this may provide a rationale for anti-CD20 therapies.

Quantification of dose nonuniformities by voxel-based dosimetry in patients receiving 90Y-ibritumomab-tiuxetan

Abstract Objective: To assess the impact of nonuniform dose distribution within lesions and tumor-involved organs of patients receiving Zevalin(®), and to discuss possible implications of equivalent uniform biological effective doses (EU-BED) on treatment efficacy and toxicity. MATLAB™ -based software for voxel-based dosimetry was adopted for this purpose.

METHODS

Eleven lesions from seven patients with either indolent or aggressive non-Hodgkin lymphoma were analyzed, along with four organs with disease. Absorbed doses were estimated by a direct integration of single-voxel kinetic data from serial tomographic images. After proper corrections, differential BED distributions and surviving cell fractions were estimated, allowing for the calculation of EU-BED. To quantify dose uniformity in each target area, a heterogeneity index was defined.

RESULTS

Average doses were below those prescribed by conventional radiotherapy to eradicate lymphoma lesions. Dose heterogeneity and effect on tumor control varied among lesions, with no apparent relation to tumor mass. Although radiation doses to involved organs were safe, unexpected liver toxicity occurred in one patient who presented with a pattern of diffuse infiltration.

CONCLUSION

Voxel-based dosimetry and radiobiologic modeling can be successfully applied to lesions and tumor-involved organs, representing a methodological advance over estimation of mean absorbed doses. However, effects on tumor control and organ toxicity still cannot be easily predicted.

Usefulness of dual-time point imaging after carbonated water for the fluorodeoxyglucose positron emission imaging of peritoneal carcinomatosis in colon cancer

BACKGROUND

Fluorodeoxygluose (FDG) positron emission/computed tomography (PET/CT) is emerging as a useful tool for the diagnosis of peritoneal carcinomatosis (PC). In this study, we assessed whether dual-time point imaging can improve the accuracy of FDG PET/CT for the diagnosis of PC after colon rectal cancer (CRC).

METHODS

Thirty-nine patients with past history of CRC were evaluated. Whole-Body PET/CT scan was acquired 1 hour after tracer injection. If one or more focal areas of increased FDG uptake (standardized uptake value, SUV max>2.5) were found in the abdomen, 1 L of carbonated water was orally administered to patients and a delayed scan of the abdominal region was acquired at 2 hours. The SUV max and the mean Delta (Δ) SUV were calculated. The scintigraphic results were compared with the results of colonoscopy and histology and with the clinical follow-up.

RESULTS

Thirteen out of the 39 patients did not show any significant area of FDG uptake at the whole-body scan. The remaining 26 patients showed an overall number of 27 sites of focal increased uptake, showing a mean SUV max of 6.5+3.3. Late scan of the abdomen showed vanishing spots in 11 cases. Focal and increasing FDG uptake was found in 15 subjects (for an overall number of 16 sites) with SUV max of 15.6+4 and mean Δ SUV of +26.3%±7.5%. In these cases, final diagnosis was PC in 10 patients (according to cytology or histology) and dysplastic polyp in 5 cases. No significant difference in Δ SUV was found between patients with PC and those with polypoid formations.

CONCLUSIONS

According to our results, dual-time point imaging after carbonated water may increase the accuracy of FDG PET/CT for the imaging of PC in patients affected by CRC.

Non-sentinel lymph node metastases in breast cancer patients with a positive sentinel lymph node: validation of five nomograms and development of a new predictive model

AIMS AND BACKGROUND

Discordance of intraoperative analysis with definitive histology of the sentinel lymph node in breast cancer leads to completion axillary lymph node dissection, which only in 35-50% shows additional nodal metastases. The aim of the study was to identify individual patient risk for non-sentinel lymph node metastases by validating several statistical methods present in the recent literature and by developing a new tool with the final goal of avoiding unnecessary completion axillary lymph node dissection.

METHODS

We retrospectively evaluated 593 primary breast cancer patients. Completion axillary lymph node dissection was performed in 139 with a positive sentinel lymph node. The predictive accuracy of five published nomograms (MSKCC, Tenon, Cambridge, Stanford and Gur) was measured by the area under the receiver operating characteristic curve. We then developed a new logistic regression model to compare performance. Our model was validated by the leave-one-out cross-validation method.

RESULTS

In 53 cases (38%), we found at least one metastatic non-sentinel lymph node. All the selected nomograms showed values greater than the 0.70 threshold, and our model reported a value of 0.77 (confidence interval = 0.69-0.86 and error rate = 0.28) and 0.72 (confidence interval = 0.63-0.81, error rate = 0.28) after the validation. With a 5% cutoff value, sensitivity was 98% and specificity 9%, for a cutoff of 10%, 96% and 2%, respectively.

CONCLUSIONS

All the nomograms were good discriminators, but the alternative developed model showed the best predictive accuracy in this Italian breast cancer sample. We still confirm that these models, very accurate in the institution of origin, require a new validation if used on other populations of patients.

Clinical indications to the use of (99m)Tc-EDDA/HYNIC-TOC to detect somatostatin receptor-positive neuroendocrine tumors

The aim of this study was to define, retrospectively, the utility to perform (99m)Tc-EDDA/HYNIC-Tyr3-octreotide ((99m)Tc-EDDA/HYNIC-TOC) scan in patients with NET. We studied 50 consecutive patients affected by different types of NET and divided in two groups. Group 1: 34 patients with known lesions in which (99m)Tc-EDDA/HYNIC-TOC was performed for staging, characterisation or to choose the appropriate treatment. Group 2: 16 patients suspected of having NET or in follow up after surgery. Patients were injected with 370 MBq of (99m)Tc-EDDA/HYNIC-Tyr3-octreotide and whole-body and SPET images acquired 2-3 hours after injection. Overall, 29 patients (58%) had a positive scan, with a sensitivity, specificity and accuracy of 70.3%, 76.9% and 72%, respectively (78.1%, 50% and 76.5%, in group 1 and 20%, 81.2%, 62.5% in group 2). In patients from group 1 (99m)Tc-HYNIC-TOC scintigraphy showed a concordance of 68% with another imaging procedure and in 9 patients revealed a greater number of lesions. In the second group, false negative results were especially found in patients with medullary thyroid cancer with negative radiological findings and elevated calcitonin. In conclusion, (99m)Tc-EDDA/HYNIC-TOC is highly indicated for in vivo histological characterization of known NET lesions, previously identified by other imaging modalities or biopsy, to plan appropriate therapy especially for patients with inoperable disease. In patients with only biochemical suspicion of NET and in those with negative markers, this scintigraphy does not significantly modify the clinical management.

Follicular lymphoma at relapse after rituximab containing regimens: comparison of time to event intervals prior to and after 90 Y-ibritumomab-tiuxetan

Radioimmunotherapies with Zevalin® (RIT-Z) showed encouraging results in patients with relapsed/refractory follicular lymphoma (FL), leading frequently to failure-free intervals longer than those achieved by the last previous therapy. We compared time-to-event variables obtained before and after RIT-Z in patients with relapsed FL, previously exposed to rituximab. All patients with relapsed non-transformed, non-refractory, non-rituximab-naïve FL who have been treated with RIT-Z in two different centres in Europe were included. Staging and response were assessed by contrast-enhanced CT in all patients; PET/CT was performed according to local availability. Event-free survival (EFS) and time to next treatment (TTNT) following the last previous therapy and after RIT-Z were compared. Pre-therapy characteristics were tested in univariate analyses for prediction of outcomes. A description of the patterns of relapse was also provided. Among 70 patients treated, only 16 fulfilled the inclusion criteria. They were treated with a median of 3 prior lines of chemo-immunotherapies, including a median of 2 rituximab-containing regimens; 6 patients had undergone myeloablative chemotherapy with autologous stem cell rescue (ASCT). Overall response rates were 10 (62%) CR/CRu, 3 (19%) PR and 3 (19%) PD; response rates were similar in patients with prior ASCT. After RIT-Z only few patients obtained EFS and TTNT longer than after the last previous therapy. All four patients receiving rituximab maintenance were without progression 12 months after RIT-Z. Relapses occurred in both previously and newly involved sites; a significant association was found between the number of pathologic sites involved prior to RIT-Z and subsequent TTNT. Despite the excellent response rate, the duration of response was shorter than the previous one confirming the known trend of relapses to occur earlier after subsequent treatments. Rituximab maintenance after RIT-Z showed encouraging results in terms of prolonging EFS, warranting further studies.

Radioimmunotherapy of heavily pre-treated, non-Hodgkin's lymphoma patients: efficacy and safety in a routine setting

The aim of the present study waw to assess efficacy and safety of radio-immunotherapy with Zevalin (RIT-Z) in heavily pre-treated, rituximab-refractory patients.

PATIENTS AND METHODS

We studied 12 patients with indolent lymphoma and 7 with aggressive lymphoma. The median number of prior rituximab-containing treatments was 2; overall, 3 therapies had been previously given. Ten patients received RIT-Z as salvage therapy, 9 at high risk of relapse received RIT-Z as consolidation. Staging and follow-up were obtained by positron-emission tomography. Outcomes assessed were failure-free survival (FFS) and time to next treatment (TTNT).

RESULTS

Overall FFS and TTNT were 5 and 11 months, respectively; median follow-up 13 months. Major findings were i) no long-term remissions observed in 7 patients who had not responded to their most recent therapy and ii) lack of association between any pre-therapy variables analysed and outcomes. Different subgroups showed no difference in terms of toxicity.

CONCLUSION

We encourage the use of RIT-Z as a consolidation for pre-treated patients with both indolent and aggressive lymphoma.

Molecular imaging of rheumatoid arthritis by radiolabelled monoclonal antibodies: new imaging strategies to guide molecular therapies

The closing of the last century opened a wide variety of approaches for inflammation imaging and treatment of patients with rheumatoid arthritis (RA). The introduction of biological therapies for the management of RA started a revolution in the therapeutic armamentarium with the development of several novel monoclonal antibodies (mAbs), which can be murine, chimeric, humanised and fully human antibodies. Monoclonal antibodies specifically bind to their target, which could be adhesion molecules, activation markers, antigens or receptors, to interfere with specific inflammation pathways at the molecular level, leading to immune-modulation of the underlying pathogenic process. These new generation of mAbs can also be radiolabelled by using direct or indirect method, with a variety of nuclides, depending upon the specific diagnostic application. For studying rheumatoid arthritis patients, several monoclonal antibodies and their fragments, including anti-TNF-alpha, anti-CD20, anti-CD3, anti-CD4 and anti-E-selectin antibody, have been radiolabelled mainly with (99m)Tc or (111)In. Scintigraphy with these radiolabelled antibodies may offer an exciting possibility for the study of RA patients and holds two types of information: (1) it allows better staging of the disease and diagnosis of the state of activity by early detection of inflamed joints that might be difficult to assess; (2) it might provide a possibility to perform 'evidence-based biological therapy' of arthritis with a view to assessing whether an antibody will localise in an inflamed joint before using the same unlabelled antibody therapeutically. This might prove particularly important for the selection of patients to be treated since biological therapies can be associated with severe side-effects and are considerably expensive. This article reviews the use of radiolabelled mAbs in the study of RA with particular emphasis on the use of different radiolabelled monoclonal antibodies for therapy decision-making and follow-up.

Central and peripheral dopamine transporter reduction in Parkinson's disease

OBJECTIVE

Previous reports showed the reduction of dopamine transporter immunoreactivity in peripheral blood lymphocytes in Parkinson's disease. In this work, we sought to investigate the possible correlation between central and peripheral dopamine transporter immunoreactivity values in a group of 11 drug-naive patients with Parkinson's disease.

METHODS

Densitometric measurements of dopamine transporter immunoreactivity in peripheral blood lymphocytes was accomplished as described recently, using a monoclonal antidopamine transporter antibody. Dopamine transporter binding in the caudate and putamen nuclei was measured by means of (123)I-fluopane single-photon emission computed tomography in the same patients.

RESULTS

The results failed to show any significant correlation between dopamine transporter immunoreactivity in peripheral blood lymphocytes and the caudate or putamen dopamine transporter binding. Moreover, dopamine transporter immunoreactivity in peripheral blood lymphocytes was reduced also in the single patient with normal striatal dopamine transporter binding.

DISCUSSION

These results indicate the lack of correlation between central and peripheral dopamine transporter reduction in Parkinson's disease, using the methodologies applied herein. They therefore suggest that the two phenomena are unlikely to share a common pathogenetic mechanism.

Thyroid cancer imaging in vivo by targeting the anti-apoptotic molecule galectin-3

Background

The prevalence of thyroid nodules increases with age, average 4–7% for the U.S.A. adult population, but it is much higher (19–67%) when sub-clinical nodules are considered. About 90% of these lesions are benign and a reliable approach to their preoperative characterization is necessary. Unfortunately conventional thyroid scintigraphy does not allow the distinction among benign and malignant thyroid proliferations but it provides only functional information (cold or hot nodules).

The expression of the anti-apoptotic molecule galectin-3 is restricted to cancer cells and this feature has potential diagnostic and therapeutic implications. We show here the possibility to obtain thyroid cancer imaging in vivo by targeting galectin-3.

Methods

The galectin-3 based thyroid immuno-scintigraphy uses as radiotracer a specific ^99mTc-radiolabeled mAb. A position-sensitive high-resolution mini-gamma camera was used as imaging capture device. Human galectin-3 positive thyroid cancer xenografts (ARO) and galectin-3 knockout tumors were used as targets in different experiments in vivo. 38 mice with tumor mass of about 1 gm were injected in the tail vein with 100 µCi of ^99mTc-labeled mAb to galectin-3 (30 µg protein/in 100 µl saline solution). Tumor images were acquired at 1 hr, 3 hrs, 6 hrs, 9 hrs and 24 hrs post injection by using the mini-gamma camera.

Findings

Results from different consecutive experiments show an optimal visualization of thyroid cancer xenografts between 6 and 9 hours from injection of the radiotracer. Galectin-3 negative tumors were not detected at all. At 6 hrs post-injection galectin-3 expressing tumors were correctly visualized, while the whole-body activity had essentially cleared.

Conclusions

These results demonstrate the possibility to distinguish preoperatively benign from malignant thyroid nodules by using a specific galectin-3 radio-immunotargeting. In vivo imaging of thyroid cancer may allow a better selection of patients referred to surgery. The possibility to apply this method for imaging and treatment of other galectin-3 expressing tumors is also discussed.

Prognostic value of FDG uptake by the bone marrow in squamous cell carcinoma of the head and neck

BACKGROUND

The appearance of natural suppressor cells and circulating endothelial progenitor cells in tumour tissue has been associated with myelopoetic stimulation by growth factors that may increase fluorodeoxyglucose (FDG) uptake by the bone marrow and high FDG uptake by bone marrow in patients suffering from human malignancies is a not uncommon finding.

METHODS

This study looked at the relationship between bone marrow FDG uptake, biochemical (Hb level, RBC count, WBC count and platelet count), clinical and radiological findings and outcome in a series of 35 patients suffering from squamous cell carcinoma of the head and neck (SCCHN), consecutively referred for FDG PET as part of their routine staging procedure.

RESULTS AND CONCLUSION

In SCCHN, mean FDG standardized uptake values (SUVs) of the primary tumour correlate significantly with blood WBC count (r=0.44; P=0.011, Bonferroni corrected P=0.04) and mean FDG SUVs of bone marrow are significantly correlated to the maximum FDG SUVs of the primary tumour (r=0.523; P=0.002). Finally, FDG uptake by the bone marrow is related to disease-free and overall survival. These findings warrant confirmation in a larger patient series.