Spinal Infection Multidisciplinary Management Project (SIMP): From Diagnosis to Treatment Guideline

Spine infections require a multidisciplinary approach to be treated and solved. A guide line to drive physicians in the deep complexity of such a disease is extremely helpful. SIMP suggests a flow-chart built up on clear concepts such as right and well managed antibiotic therapy, sound stability of the spine, correct and smart use of the standard and functional imaging techniques, such as f18 FDG PET/CT. In 16 months a total of 41 patients have been treated for spondylodiscitis, discitis and vertebral osteomyelitis by our team of physicians and 25 patients have been enrolled in a prospective study whose target is the assessment of the SIMP flow-chart and of every single aspect that characterize it.

18[F]FDG small animal PET study of sorafenib efficacy in lymphoma preclinical models

AIM

Kinase inhibitors have been proposed as novel therapeutic agents in different forms of solid tumours. The Food and Drug Administration (FDA) approved the use of Sorafenib, an oral multikinase inhibitor, for advanced renal carcinoma and unresectable hepatocellular carcinoma. On-going studies are investigating the efficacy of Sorafenib in other solid tumours such as melanoma and non-small cells lung carcinoma and pre-clinical models showed the efficacy of treatment with Sorafenib in murine models of renal cells carcinoma, breast cancer, colon carcinoma and melanoma. To our knowledge, Sorafenib has never been employed in human lymphoma. The aim of the present study was to assess the efficacy of Sorafenib in murine models of human anaplastic large cells lymphoma (ALCL) and Hodgkin lymphoma (HD).

METHODS

Sorafenib cytotoxicity was assessed in vitro and growth inhibition (IC50) was calculated. Cells were assayed for Caspase-3 to measure apoptosis. Human ALCL and HD xenografts in NOD/SCID mice were monitored by small animal positron emission tomography (PET) and computed tomography (CT) over time. Tumour bearing animals were randomly selected to receive treatment with Sorafenib or no treatment. Pathology was available in all cases.

RESULTS

Sorafenib efficacy on cells proliferation and apoptosis (IC50: HD=0.0343 mg/L; ALCL=0.319 mg/L) was confirmed in vitro. Caspase-3 production showed a dose-dependent trend reaching significantly higher values for 0.046 mg/L and 0.465 mg/L drug concentrations in both cell lines. In vivo experiments showed a progressive increase of tumour lesions metabolism and dimensions regardless treatment.

CONCLUSION

Sorafenib showed a good cytotoxic effect in vitro especially on human HD cell line, but these findings were not confirmed in vivo. The strong discrepancy between in vitro and in vivo results suggests that further studies are needed to better acknowledge the biodistribution and metabolism of Sorafenib in NOD/SCID mice. Factors influencing drug availability at tumour site or differences in the downstream pathways may be responsible for the scarse effect of treatment.

Non FDG PET

2- [(18)F]-fluoro-2-deoxy-D-glucose (FDG) is the radiopharmaceutical most frequently used for clinical positron emission tomography (PET). However, FDG cannot be used for many oncological, cardiological, or neurological conditions, either because the abnormal tissue does not concentrate it, or because the tissues under investigation demonstrate high physiological glucose uptake. Consequently, alternative PET tracers have been produced and introduced into clinical practice. The most important compounds in routine practice are (11)C-choline and (18)F-choline, mainly for the evaluation of prostate cancer; (1)C-methionine for brain tumours; (118)F-DOPA ((18)F-deoxiphenilalanine) for neuroendocrine tumours and movement disorders; (68)Ga-DOTANOC (tetraazacyclododecanetetraacetic acid-[1-Nal3]-octreotide) and other somatostatin analogues for neuroendocrine tumours; 11C-acetate for prostate cancer and hepatic masses and 18F-FLT (3-deoxy-3-fluorothymidine) for a number of malignant tumours. Another impetus for the development of new tracers is to enable the investigation of biological processes in tumours other than glucose metabolism. This is especially important in the field of response assessment, where there are new agents that are targeted more specifically at angiogenesis, hypoxia, apoptosis and other processes.

[The document of chemical risk assessment: experiences in small companies]

Were examined 60 documents of chemical risk assessment of companies from 19 municipalities in the provinces of Siena and Grosseto. The review of evaluations was conducted initially by checking the internal coherence of the documents. What emerged was subsequently analyzed together with the staff who performed the inspection. Although in 12 companies has been declared the presence of carcinogens, in only 5 the evaluation of exposure have been done using measures, others have used models or other techniques. Overall assessment showed that only 8 out of 60 (13.3%) were wrote correctly.

Advances in preclinical therapeutics development using small animal imaging and molecular analyses: the gastrointestinal stromal tumors model

The large use of target therapies in the treatment of gastrointestinal stromal tumors (GISTs) highlighted the urgency to integrate new molecular imaging technologies, to develop new criteria for tumor response evaluation and to reach a more comprehensive definition of the molecular target. These aspects, which come from clinical experiences, are not considered enough in preclinical research studies which aim to evaluate the efficacy of new drugs or new combination of drugs with molecular target. We developed a xenograft animal model GIST882 using nude mice. We evaluated both the molecular and functional characterization of the tumor mass. The mutational analysis of KIT receptor of the GIST882 cell lines and tumor mass showed a mutation on exon 13 that was still present after in vivo cell growth. The glucose metabolism and cell proliferation was evaluated with a small animal PET using both FDG and FLT. The experimental development of new therapies for GIST treatment requires sophisticated animal models in order to represent the tumor molecular heterogeneity already demonstrated in the clinical setting and in order to evaluate the efficacy of the treatment also considering the inhibition of tumor metabolism, and not only considering the change in size of tumors. This approach of cancer research on GISTs is crucial and essential for innovative perspectives that could cross over to other types of cancer.

Positron-emission tomography in imaging and staging prostate cancer

With increasing application of positron-emission tomography (PET) imaging, familiarity with the applications of PET in genitourinary oncology, especially prostate-cancer (PCa) imaging, becomes important. PET studies provide functional information using radiolabeled tracers, with fluoro-dexoxy-glucose (FDG) being the most commonly used. Nevertheless FDG has limitations for evaluation of PCa patients and therefore alternative tracers are being investigated. To date, the best results have been obtained with 11C-choline and 11C-acetate PET, which seem to demonstrate similar values in this field. We review the current role of PET in PCa patients based on data published in the literature as well as our own experience. Most studies of PET imaging of PCa address three goals: a) detecting primary PCa; b) staging PCa; and c) assessing PCa recurrence. From available results, routine clinical use of 11C-choline PET cannot be recommended for detecting and staging primary PCa. At present, the only clinical indication for imaging PCa with 11C-choline-PET is evaluation of suspected recurrence after treatment.

Experimental results and related clinical implications of PET detection of epidermal growth factor receptor (EGFr) in cancer

The epidermal growth factor receptor (EGFr) is one of the most studied molecules as a target for cancer therapy. Over these last few years, several studies attempting to identify predictive biomarkers of treatment response, such as the receptor status or other molecules related to the downstream signalling pathway, have been conducted. However, from a clinical point of view, the information obtained from ex vivo analyses still has various limitations that may be overcome by the combination with molecular imaging technologies which may provide a noninvasive, global, in vivo evaluation of the molecular tumour background. The aim of this review is to report the preclinical results of all positron emission tomography (PET) tracers synthesized until now for in vivo detection of EGFr in cancer. Two classes of PET compounds have been developed: labelled small molecules such as tyrosine kinase inhibitors and labelled monoclonal antibodies. The in vitro and in vivo results of these PET tracers are very different depending on the chemical properties, positron emission radionuclide, or animal models. As a consequence, various critical questions are still open, and the implications of a translation in the clinical setting for EGFr imaging in cancer patients is discussed.

Molecular imaging and targeted therapies in oncology: new concepts in treatment response assessment. a collection of cases

The widespread use of several new non-cytotoxic drugs and the significant improvements in functional imaging highlights a number of difficulties in monitoring, interpreting and predicting treatment response in clinical practice. Certain guidelines for disease assessment after therapy are already available: the traditional Response Evaluation Criteria in Solid Tumours guidelines based on tumour size variations using conventional imaging technologies, the recent combined method developed by Choi and colleagues in gastrointestinal stromal tumour treated with tyrosine kinase inhibitors based on tumour density variations using computed tomography (CT), and the European Organization for Research and Treatment of Cancer criteria based on tumour glucose metabolism variations using fluorodeoxyglucose (FDG) positron emission tomography (PET). At the moment combined PET/CT response criteria are still not available. A number of new PET compounds other than FDG are also currently being developed to visualize specific cellular and molecular tumour pathways but their role in assessment and prediction of cancer treatment response has not yet been thoroughly investigated in a large series. However, in clinical practice many oncologists treat cancer patients with targeted therapies or chemotherapy and evaluate the response using conventional or functional imaging without appropriate and standardized guidelines. The aim of this study was to present a selection of clinical cases that illustrate the usefulness of new PET tracers and efficacy evaluation of new drugs. In the era of molecular imaging and molecular therapies, these cases highlight the urgency to develop new criteria for treatment assessment and the exigency of correctly interpreting the biological information obtained from new technologies, and introduce new concepts that require further investigation in clinical trials.

Clinical applications of 68Ga-DOTANOC in neuroendocrine tumours

Neuroendocrine tumours (NET) are relatively rare neoplasms affecting principally the gastroenteropancreatic tract, but with potential ubiquitary location, as the neural crest cells, origin of this group of tumours, are dispersed in various organs and tissues. After the discovery of somatostatin receptors (SSTR) over-expression in this group of neoplasms, NET management has significantly improved. This is witnessed by the development of new tracers in positron emission tomography (PET) imaging of NETs belonging to the family of radio-labelled somatostatin analogues, that significantly improved the accuracy of diagnosis and, more recently, opened the way to the innovative targeted radionuclide therapies. First introduced in clinical application in 2005, 68Ga-DOTANOC (one of the most used radio-labelled somatostatin analog for PET imaging) has revealed promising results in preliminary studies for the main clinical indications: staging NET; suspected NET of unknown primary; follow-up, restaging and, finally, for pre- and post-treatment evaluation of receptor radionuclide therapies. Due to its technically simple production, favourable biodistribution, biokinetics, dosimetry and high affinity for SSTR and thanks to the possibility of hybrid scans PET/computed tomography (CT) with better spatial resolution and localisation of the lesions, 68Ga-DOTANOC can advance as the new gold standard for imaging in neuroendocrine tumours.

18F-FDG small animal PET for early detection of human anaplastic large cells lymphoma xenograft in immunocompromised mice

The purpose of the present study was to assess if small animal PET is useful for serially monitoring the development of a human anaplastic large cell lymphoma (ALCL) murine xenograft and for the early selection of tumour bearing animals. The human ALCL Karpas 299 cell line was subcutaneously injected in 6-week-old NOD/SCID (non-obese diabetic/NCrCrl- Prkdc) mice (10(7) cells/mouce in 150 pil FBS) at the right flank level. Small animal 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) was serially performed (intravenous injected dose: 20 MBq in < 0.15 ml, uptake time: 60 min, image acquisition: 1 bed position of 15 min): early PET at 2 days after cell inoculation in 4/8 mice and at 4 days in the remainig 4/8, later PET scans were performed in all the animals at 7, 14, 21 and 28 days after inoculation. The images were evaluated visually and the tumour to background ratio (TBR) was used for semiquantitative analysis. Pathology sections were obtained in all cases. PET detected the presence of the tumour as early as seven days after inoculation in 4/8 mice and at 14 days in 2/8. Of the two remaining mice, one died after the first PET scan (thus preventing any evaluation of detection time) while the other showed a microscopic neoplastic infiltration at tracheal level at autopsy. Mean TBR progressively increased in all positive cases, particularly in the first 3 weeks, reaching a plateau afterwards. PET was positive in 6/8 (75%) animals, detecting the presence of viable tumour cells earlier than macroscopic evaluation, thus may be used for the early identification of tumour bearing animals.

Conventional and novel PET tracers for imaging in oncology in the era of molecular therapy

In the last ten years, the development of several novel targeted drugs and the refinement of state of the art technologies such as the genomics and proteomics and their introduction to clinical practice have revolutionized the management of patients affected by cancer. However, everyday practice points out several clinical questions: the difficulty of response assessment to new drugs especially using standard RECIST criteria that do not provide information on biological, vascular or metabolic variations; the inadequate selection of patients who are likely to benefit from a targeted therapy excluding those with breast cancer and gastrointestinal stromal tumours; the need to know the global biological background of diseases especially in metastatic setting using repeatable non-invasive procedures. Molecular imaging could provide information on in vivo distribution of biological markers in response to targeted therapy and could improve the selection of patients before therapies. The aim of this review is to analyze the current role of conventional and innovative positron emission tomography (PET) radiotracers in clinical practice and to explore the promising perspectives of molecular imaging in cancer research.

Gallium-68 PET: a new frontier in receptor cancer imaging

Neuroendocrine tumours (NET) are rare tumours that occur most commonly in the GI tract. Various labelled somatostatin analogues are used to image NET expressing somatostatin receptors (SSTR). In traditional nuclear medicine, most peptides used in imaging NET have been labelled with indium-111, the commonest being indium-111-octreotide (111In-octreotide). Unfortunately, the unfavourable physical qualities of In-111 make it unsuitable for detecting small tumour deposits. The recent introduction of gallium-68-1,4, 7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (gallium-68-DOTA) compounds for positron emission tomography (PET) imaging has significantly improved the quality of imaging NET through improved resolution of PET and higher affinity of the new generation of peptides to SSTR. In the present paper, we discuss the clinical and research applications of PET radio-tracers for evaluating NET, in particular gallium-68-DOTA compounds. The recent introduction of PET imaging with gallium-68 has major bearings in current and future clinical practice. Its labelling with DOTA compounds has cleared the way for somatostatin receptor imaging with a viable PET agent, with all its inherent imaging advantages compared to single photon imaging. The pre-clinical and clinical applications of this technique has been successful in a variety of tumours, particularly NET and its labelling with other ligands and molecules will improve the management of other tumours and the assessment of infection.

The role of 18F-FDG PET/CT in detecting metastatic deposits of recurrent medullary thyroid carcinoma: a prospective study

AIM

To assess the diagnostic role of 18F-FDG PET/CT performed with a hybrid tomograph in the detection of tumoral deposits of recurrent medullary thyroid carcinoma (MTC).

METHODS

Nineteen MTC patients with elevated serum calcitonin levels (58-1350 pg/ml) after first treatment were enrolled (11 F, 8 M, mean age 53.4 years, 14 sporadic MTC, 5 MEN-related MTC). All patients had previously undergone total thyroidectomy and lymphoadenectomy. When referred to us, they were studied with ultrasound (US), 18F-FDG PET/CT, (111)In-pentetreotide scan, and contrast-enhanced whole-body CT (c.e. CT). In 4 patients with equivocal abdominal findings at 18F-FDG PET/CT and/or at c.e. CT, laparoscopy was also performed.

RESULTS

18F-FGD PET/CT depicted metastases in 15 patients, 111In-pentetreotide in 8, c.e. CT in 11, US in 6. In 2 patients, liver micrometastases were detected at laparoscopy only. At a lesion-by-lesion analysis, 18F-FDG PET/CT visualized a total of 26 metastatic deposits, c.e. CT 18, 111In-pentetreotide 12, US 8. Final diagnosis was obtained by cytological or surgical findings. Four patients with evidence of limited metastatic spread to neck/upper mediastinum were re-operated, and in 2 of them serum calcitonin levels normalized.

CONCLUSIONS

In our study, 18F-FDG PET/CT was the most sensitive imaging modality in detecting metastases in recurrent MTC patients with increased serum calcitonin levels. Moreover, 18F-FDG PET/CT was useful in some patients to plan a more accurate re-operation. From a diagnostic point of view, a multimodality imaging approach is recommended in recurrent MTC, especially based on the combination of c.e. CT and 18F-FDG PET/CT.

68Ga-DOTANOC: biodistribution and dosimetry in patients affected by neuroendocrine tumors

OBJECTIVES

The aim of this work was the evaluation of biodistribution and radiation dosimetry of (68)Ga-DOTANOC in patients affected by neuroendocrine tumors.

MATERIALS AND METHODS

We enrolled nine patients (six male and three female) affected by different types of neuroendocrine tumors (NETs). Each patient underwent four whole body positron emission tomography (PET) scans, respectively, at 5, 20, 60, and 120 min after the intravenous injection of about 185 MBq of (68)Ga-DOTANOC. Blood and urine samples were taken at different time points post injection: respectively, at about 5, 18, 40, 60, and 120 min for blood and every 40-50 min from injection time up to 4 h for urine. The organs involved in the dosimetric evaluations were liver, heart, spleen, kidneys, lungs, pituitary gland, and urinary bladder. Dosimetric evaluations were done using the OLINDA/EXM 1.0 software.

RESULTS

A physiological uptake of (68)Ga-DOTANOC was seen in all patients in the pituitary gland, the spleen, the liver, and the urinary tract (kidneys and urinary bladder). Organs with the highest absorbed doses were kidneys (9.0E-02+/-3.2E-02mSv/MBq). The mean effective dose equivalent (EDE) was 2.5E-02+/-4.6E-03 mSv/MBq.

DISCUSSION AND CONCLUSIONS

The excretion of the compound was principally via urine, giving dose to the kidney and the urinary bladder wall. As SSTR2 is the most frequently expressed somatostatin receptor and (68)Ga-DOTANOC has high affinity to it, this compound might play an important role in PET oncology in the future. The dosimetric evaluation carried out by our team demonstrated that (68)Ga-DOTANOC delivers a dose to organs comparable to, and even lower than, analogous diagnostic compounds.

PET in genitourinary tract cancers

Genitourinary (GU) tract cancers comprise a variety of tumors, which includes some of the most common malignancies in men and women. As a result of the importance of GU neoplasms and the success of positron emission tomography (PET) in imaging and staging cancer, PET with fluorodeoxyglucose (FDG) has been used to depict and stage ovarian, cervical and testicular cancers. The early success of FDG PET in imaging GU tumors is tempered by the fact that some neoplasms of GU origin do not accumulate sufficient FDG for successful imaging. As a result, alternative agents, such as [11C]choline and [11C]acetate, have been used to image prostate cancer and may have utility in bladder cancer, while other PET agents are currently under active evaluation for this and other GU neoplasms. In this paper, we review the current literature and our experience in role of PET in imaging cancers of the GU tract.

18F-FDG PET/CT in the assessment of carcinoma of unknown primary origin

PURPOSE

Metastatic cancers of unknown primary origin are characterised by a poor prognosis, with a survival rate from diagnosis of approximately 12 months. Conventional radiological imaging allows detection of 20%-27% of primary cancers, whereas the detection rate with positron emission tomography (PET) is 24%-40%. The aim of this study was to assess the role of 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) in the identification of occult primary cancers.

MATERIALS AND METHODS

The study population consisted of 38 consecutive patients with histologically proven metastatic disease and negative or nonconclusive conventional diagnostic procedures. All patients were studied by 18F-FDG PET performed according to the standard procedure (6 h of fasting, intravenous injection of 370 MBq 18F-FDG, and image acquisition with a PET/CT scanner for 4 min per bed position).

RESULTS

18F-FDG-PET/CT detected the occult primary cancer in 20 cases (53%), showing higher sensitivity than that reported for any other imaging modality, including PET.

CONCLUSIONS

The encouraging results, if validated by larger series, support the use of PET/CT in patients with carcinoma of unknown primary origin and negative conventional imaging results.

Sentinel lymph node (SLN) procedure with patent V blue dye in 153 patients with papillary thyroid carcinoma (PTC): is it an accurate staging method?

The present study aims to evaluate the accuracy of sentinel lymph node (SLN) mapping performed by intratumoral injection of blue dye in a large series of patients with papillary thyroid cancer (PTC). 153 consecutive patients were enrolled in the study. All patients had a preoperative cytological diagnosis of PTC, and none had clinical or ultrasonographic (US) evidence of nodal involvement. At surgery, vital patent V blue dye was injected into the malignant thyroid nodule. Subsequently, total thyroidectomy, central compartment (CC) node dissection, and median inferior jugulocarotid node dissection of laterocervical compartment, ipsilateral to the primary tumour, were performed. The excised thyroid, the blue-positive SLN and blue-negative lymph nodes were sent for frozen section and definitive histophatologic analysis. At surgery, blue-positive SLN were found in 107/153 patients (69.9%), of whom 36 (33.6%) had micrometastasis in SLN; moreover, in 13 of these 36 patients (36.1%), other nodes were found to be metastatic. In the remaining 71/107 blue-positive SLN patients, both the SLN itself and the other removed nodes were found negative for the presence of metastatic disease. In 4 cases, a normal parathyroid gland and in 3 cases fibro-adipous tissue were blue-stained and mistakenly removed as SLN (7 false positive results). On the other hand, SLN was blue-negative in 46/153 patients (30.1%), of whom 7 patients (15.2%) had micrometastases in blue-negative lymph nodes. On the basis of these data, the blue dye procedure for SLN detection appears inappropriate as a standard of care in PTC due to a relatively high number of false negative and false positive results.

18F-FDG PET/CT fusion imaging in paediatric solid extracranial tumours

This paper aims at discussing the utility of 18F-FDG PET/CT in the evaluation of paediatric solid extracranial tumours. Following a brief discussion of the basic principles and methodology of PET/CT system, it reviews the main characteristics of the tumours that can be visualised with 18F-FDG PET and presents examples of cases where the combined use of 18F-FDG PET/CT fusion imaging helped in the management of patients. It will also discuss the physiologic biodistribution of 18F-FDG, outlining the normal variants in the paediatric patients that may lead to misinterpretation.

Artefacts of PET/CT images

Positron emission tomography (PET) is a non-invasive imaging modality, which is clinically widely used both for diagnosis and accessing therapy response in oncology, cardiology and neurology.Fusing PET and CT images in a single dataset would be useful for physicians who could read the functional and the anatomical aspects of a disease in a single shot.The use of fusion software has been replaced in the last few years by integrated PET/CT systems, which combine a PET and a CT scanner in the same gantry. CT images have the double function to correct PET images for attenuation and can fuse with PET for a better visualization and localization of lesions. The use of CT for attenuation correction yields several advantages in terms of accuracy and patient comfort, but can also introduce several artefacts on PET-corrected images.PET/CT image artefacts are due primarily to metallic implants, respiratory motion, use of contrast media and image truncation. This paper reviews different types artefacts and their correction methods.PET/CT improves image quality and image accuracy. However, to avoid possible pitfalls the simultaneous display of both Computed Tomography Attenuation Corrected (CTAC) and non corrected PET images, side by side with CT images is strongly recommended.