Federica Orsini

Current role of 111In-DTPA-octreotide scintigraphy in diagnosis of thymic masses.

AIMS AND BACKGROUND Thymic tumors (thymomas and thymic carcinomas) represent 50% of all mediastinal tumors. Thymomas usually express high levels of somatostatin receptors, which enable in vivo imaging with 111In-DTPA-octreotide (OctreoScan®). The aim of this study was to further investigate the role of radionuclide techniques in the diagnosis, staging and follow-up of these tumors. METHODS Eight patients (5 women, 3 men, age range 35-79 years; mean ± SD 56.1 ± 15.8 years) entered the study. In 4 patients, myasthenia gravis was the presenting symptom. 111In-DTPA-octreotide scan was performed within 3 weeks after contrast enhanced CT and/or MRI. Planar and tomographic images were acquired within 24 hours of the injection of 111 MBq OctreoScan. The scintigraphic results were defined in correlation with the histological findings. RESULTS Histology revealed thymoma in 3 patients, thymic carcinoma in 1, insular carcinoma of presumably thymic origin in 1, thymic carcinoid in 1, and thymic hyperplasia in 2 patients. Two thymomas were at stage I, 1 thymoma and 1 thymic carcinoma at stage II, 1 insular carcinoma of presumably thymic origin at stage IV, and 1 thymic carcinoid at stage IV. OctreoScan consistently accumulated in primary and/or metastatic sites of thymic tumors while no radiotracer uptake was detected in the 2 patients with benign thymic hyperplasia. In 1 patient with a very large mediastinal mass (13 cm in largest diameter) and multiple metastatic deposits in the lungs, OctreoScan scintigraphy showed a large area of pathological uptake in the anterior mediastinum and a small area of focal uptake in the cervical-dorsal region of the right lung corresponding to a lymph node expressing somatostatin receptors. CONCLUSIONS OctreoScan is avidly taken up by thymic tumors, enabling the diagnosis of these tumors and a better evaluation of their extension. It does not accumulate in thymic hyperplasia, thus allowing the differential diagnosis between these 2 pathological conditions. In patients affected by myasthenia gravis, OctreoScan scintigraphy can play an important role in characterizing thymic masses.

Radiopharmaceuticals for Single-Photon Emission Imaging and for Therapy

Radiopharmaceuticals contain a radionuclide and an agent to direct the radionuclide to a receptor, antigen, ionic pump, or other site of interest. Some radiopharmaceuticals are simple, such as the ionic form of the radionuclide, while most radiopharmaceuticals have a complex chemical structure where the radionuclide provides a signal, indicating the site of localization of the carrier molecule. Common single-photon radiopharmaceuticals used for diagnosis 99mTc 99mTc-Bisphosphonates accumulate at sites of bone mineral rearrangement 99mTc-Labeled colloids are used for lymphoscintigraphy and imaging liver and spleen 99mTc-Hexakis-methoxy-isobutyl-isonitrile and 99mTc-tetrofosmin (a lipophilic cationic diphosphine) are used for myocardial perfusion imaging, identification of parathyroid adenoma, and identification of some tumors 123I or 131I Iodide—localization of thyroid tissue Metaiodobenzylguanidine (MIBG), a catecholamine analog, localizing in pheochromocytoma and neuroblastoma 201Tl Ionic thallium used for tumor perfusion imaging 111In-Pentetreotide Detects overexpression of somatostatin receptors, especially in neuroendocrine tumors and lesions arising from the neural crest, such as carcinoid, paragangliomas, and medullary thyroid carcinomas 111In-Capromab pendetide Capromab pendetide is a murine monoclonal antibody which recognizes a transmembrane glycoprotein expressed by poorly differentiated and metastatic prostate adenocarcinomas 67Ga-Citrate Gallium forms a complex with transferrin or lactoferrin. Receptors for this complex are overexpressed on membranes of tumor and inflammatory cells Common single-photon radiopharmaceuticals for therapy 131I For treatment of thyroid cancer and radioimmune therapy of lymphoma 153Sm-EDTMP and 89SrCl For treatment of intractable bone pain 90Y For radioimmune therapy of lymphoma, radiopeptide therapy of neuroendocrine tumors, and complexed to resin particles or glass spheres for intra-arterial radioembolization therapy of hypervascularized tumors of the liver Experimental agents for therapy include 89Zr and 177Lu for immune and peptide therapy as well as alpha emitters from 223Ra, 211At, 212Bi, 213Bi, and 225Ac for treating intractable bone pain and radioimmune therapy

Role of molecular imaging in the management of patients affected by inflammatory bowel disease: State-of-the-art

AIM To present the current state-of-the art of molecular imaging in the management of patients affected by inflammatory bowel disease (IBD). METHODS A systematic review of the literature was performed in order to find important original articles on the role of molecular imaging in the management of patients affected by IBD. The search was updated until February 2016 and limited to articles in English. RESULTS Fifty-five original articles were included in this review, highlighting the role of single photon emission tomography and positron emission tomography. CONCLUSION To date, molecular imaging represents a useful tool to detect active disease in IBD. However, the available data need to be validated in prospective multicenter studies on larger patient samples.

Thyroid Ultrasound and Other Imaging Procedures in the Pediatric Age

The purpose of this review is to provide a reappraisal of the diagnostic imaging procedures for thyroid carcinoma in pediatric patients, including thyroid ultrasound (US), ultrasound-guided fine-needle aspiration biopsy (FNAB), scintigraphy, radiological techniques (CT, MR), and PET/CT. The most frequent indication for thyroid imaging is characterization of a palpable mass in the neck or thyroid gland. Thyroid US is a first-line examination for visualizing the thyroid gland as it provides anatomic and perfusion information; on the other hand, scintigraphy mostly provides functional information but combined with some anatomic information as well. CT and MRI have a supplemental role in these patients. Furthermore, with the introduction of PET/CT and the development of new imaging agents, nuclear medicine plays an important role in different phases of neoplastic disease in terms of both staging and evaluation of response to medical/surgical treatments.

A critical reappraisal of sentinel lymph node biopsy for non-small cell lung cancer

Because of unsatisfactory accuracy of preoperative imaging and/or of mediastinoscopy, current guidelines recommend routine dissection of mediastinal lymph nodes for patients with operable non-small cell lung cancer (NSCLC). However, at final histopathology this surgical procedure, which is performed mostly for staging purposes and implies a non-negligible rate of severe complications, turns out to be unnecessary in a quite large proportion of patients with early NSCLC. These considerations explain the interest in exploring the potential of sentinel lymph node biopsy (SLNB) in patients with NSCLC, an approach based on the same rationale that has led to establish SLNB as the standard of care in patients with cutaneous melanoma or breast cancer (especially if performed with intraoperative gamma probe guidance after injection at the tumor site of a radiolabeled agent for lymphatic mapping). However, in the case of NSCLC objective anatomic difficulties prevent the possibility to access the primary tumor for injection of the lymphatic mapping agent through an easy and minimally invasive administration route and with adequate timing so to allow for adequate preoperative imaging. Although different methodological approaches have been explored to overcome these difficulties, the clinical evidence so far acquired does not justify the use of SLNB as a routine clinical procedure to stage the tumor status of mediastinal lymph nodes in patients with NSCLC. Nonetheless, the search is continuing for the optimal combination of techniques to optimize and validate the SLNB approach for NSCLC; promising perspectives in this regard include a combination of multimodal techniques, for instance intraoperative gamma probe guidance combined with detection of either an optical and/or a magnetic signal.

General Concepts on Radioguided Sentinel Lymph Node Biopsy: Preoperative Imaging, Intraoperative Gamma-Probe Guidance, Intraoperative Imaging, and Multimodality Imaging

Lymphoscintigraphy is an essential component for radio-guided sentinel lymph node biopsy (SLNB), which is now routinely employed in clinical practice for treating patients with breast cancer [1] or melanoma [2]. SLNB is used to assess the tumoral involvement of lymph nodes not only for staging (parameter N of the TNM [tumor, node, metastases] system) and prognostic stratification, but also for therapeutic purposes [3]. This procedure is part of the so-called “radioguided surgery,” a whole spectrum of nuclear medicine applications based on the combination of preoperative imaging, intraoperative detection, and postoperative techniques, involving close collaboration between at least three different specialties (nuclear medicine, surgery, pathology, and sometimes radiology and health physics as well) [4].

Preoperative and Intraoperative Lymphatic Mapping for Radioguided Sentinel Node Biopsy in Breast Cancer

Axillary lymph node status still is a major prognostic factor in early-stage breast cancer, providing information that is important for tailoring post-surgical treatment [1,2].

The Value of Oro-Pharyngo-Esophageal Scintigraphy in the Management of Patients with Aspiration into the Tracheo-bronchial Tree and Consequent Dysphagia.

Context: Tracheo-bronchial aspiration is the most invalidating condition which can happen to patients affected by dysphagia, especially when caused by central neurologic disorders; the associated pneumonia episodes represent the most frequent cause of death in these patients. Oro-pharyngo-esophageal scintigraphy (OPES) allows both functional imaging and semiquantitative evaluation of the subsequent phases of swallowing. Case Report: We evaluated by means of OPES a woman who had previously undergone high-dose external beam radiation therapy for a nasopharyngeal carcinoma, which determined tissue fibrosis and progressive dysphagia. Conclusion: In this patient with dysphagia, OPES was a simple, inexpensive, noninvasive, and reliable technique that allowed to show the presence of bolus aspiration and quantified tracheobronchial aspirate.

Functional Imaging and Peptide Receptor Radionuclide Therapy

Nuclear medicine imaging depicts the expression of certain target molecules and evaluates the functional aspects of lesions within tissues. The molecular information can be combined with the mainly anatomical information provided by other diagnostic modalities, e.g., conventional radiological imaging with ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), contrast-enhanced US (CEUS), endoscopic US (EUS), intraoperative US (IOUS), and selective angiography with hormonal sampling. Thus, nuclear medicine imaging can identify specific molecular changes linked to the target expression of macroscopic lesions within tissues.

Caratteristiche generali dei radiofarmaci

Per radiofarmaco si intende qualsiasi medicinale che, quando e pronto per l’uso a scopo medico (diagnosi e/o terapia), include uno o piu radionuclidi (nuclei radioattivi) incorporati. Questa definizione generale supera quindi la vecchia distinzione fra “tracciante” (termine originariamente riservato a molecole marcate di interesse biologico impiegate in genere per studi metabolici in vitro o in vivo) e “indicatore” (riservato, invece, a molecole marcate per uso diagnostico).