A new mobile self-dispensing and administering system for 18F-FDG: evaluation of operator dose reduction.

PURPOSE: Recently new mobile systems for dispensing positron emitters have been produced, designed to guarantee dispensing cycles in an aseptic environment. The aim of the present work was to assess the advantage of one of these systems in radiation protection of operators in clinical settings. METHODS: Recently, in our centre the new self-dispensing system named KARL100 by Tema Sinergie was adopted for 18F-FDG radiopharmaceuticals. The system is associated with an automatic Rad-inject infuser. The system that was previously used was a fixed isolator NMC DSI (Tema Sinergie), equipped with a µDDS-An activity fractioning system, together with a pneumatic post for the syringe delivery. The dosimetric evaluations on both systems were carried out through environmental measurements with an ionisation chamber and with the use of personal dosimeters. RESULTS: The operations of preparation and administration of 18F-FDG dose to the patient, with the use of Karl100 + RadInject, involve exposures much lower than those obtained by the fixed isolator. The average body exposure of the technician was reduced by 31%, and for the physician by 77%. On the extremities, the equivalent dose to the hands of the technician was reduced by 78%, and for the physician by 96%. Also the additional dosimeters worn by the technician confirmed the estimated environmental assessments. CONCLUSIONS: The exposures of the working personnel were significantly reduced with the introduction of the new KARL100 system.

(18)F-FDG PET/CT quantification in head and neck squamous cell cancer: principles, technical issues and clinical applications.

(18)F-FDG PET/CT plays a crucial role in the diagnosis and management of patients with head and neck squamous cell cancer (HNSCC). The major clinical applications of this method include diagnosing an unknown primary tumour, identifying regional lymph node involvement and distant metastases, and providing prognostic information. (18)F-FDG PET/CT is also used for precise delineation of the tumour volume for radiation therapy planning and dose painting, and for treatment response monitoring, by detecting residual or recurrent disease. Most of these applications would benefit from a quantitative approach to the disease, but the quantitative capability of (18)F-FDG PET/CT is still underused in HNSCC. Innovations in PET/CT technology promise to overcome the issues that until now have hindered the employment of dynamic procedures in clinical practice and have limited "quantification" to the evaluation of standardized uptake values (SUV), de facto a semiquantitative parameter, the limits of which are well known to the nuclear medicine community. In this paper the principles of quantitative imaging and the related technical issues are reviewed so that professionals involved in HNSCC management can reflect on the advantages of "true" quantification. A discussion is then presented on how semiquantitative information is currently used in clinical (18)F-FDG PET/CT applications in HNSCC, by discussing the improvements that could be obtained with more advanced and "personalized" quantification techniques.

Is the detection rate of 18F-choline PET/CT influenced by androgen-deprivation therapy?

PURPOSE: To evaluate if the detection rate (DR) of (18)F-choline (18F-CH) PET/CT is influenced by androgen-deprivation therapy (ADT) in patients with prostate cancer (PC) already treated with radical intent and presenting biochemical relapse. MATERIALS AND METHODS: We have retrospectively evaluated (18)F-CH PET/CT scans of 325 consecutive PC patients enrolled in the period November 2009 to December 2012 previously treated with radical intent and referred to our centre to perform (18)F-CH PET/CT for biochemical relapse. Two different groups of patients were evaluated. group A included the whole sample of 325 patients (mean age 70 years, range: 49-86) who presented trigger PSA between 0.1 and 80 ng/ml (mean 5.5 ng/ml), and group B included 187 patients (mean age 70 years, range 49-86) with medium-low levels of trigger PSA ranging between 0.5 and 5 ng/ml (mean PSA 2.1 ng/ml); group B was chosen in order to obtain a more homogeneous group of patients in terms of PSA values also excluding both very low and very high PSA levels avoiding the "a priori" higher probability of negative or positive PET scan, respectively. At the time of examination, 139 patients from group A and 72 patients from group B were under ADT: these patients were considered to be hormone-resistant PC patients because from their oncologic history (>18 months) an increase of PSA levels emerged despite the ongoing ADT. The relationship between (18)F-CH PET/CT findings and possible clinical predictors was investigated using both univariate and multivariate binary logistic regression analyses, including trigger PSA and ADT. RESULTS: Considering the whole population, overall DR of (18)F-CH PET was 58.2 % (189/325 patients). In the whole sample of patients (group A), both at the univariate and multivariate logistic regression analysis, trigger PSA and ADT were significantly correlated with the DR of (18)F-CH PET (p < 0.05). Moreover, the DR in patients under ADT (mean PSA 7.8 ng/ml) was higher than in patients not under ADT (mean PSA 3.9 ng/ml), (DR was 70.5 % and 48.9 %, respectively; p < 0.001), therefore, demonstrating the existence of a significant correlation between the DR of (18)F-CH PET and ADT. In group B patients only trigger PSA resulted a reliable predictor of the (18)F-CH positivity, since ADT was not correlated to the DR of (18)F-CH PET (p = 0.061). Also in group B the DR of (18)F-CH PET in patients under ADT was higher than in patients not under ADT (65.3 % and 51.3 %, respectively) but the difference was not significant without a statistically significant correlation in the Mann Whitney test (p = 0.456) therefore, suggesting the lack of correlation between DR (18)F-CH PET/CT and ADT. CONCLUSION: Similarly to previous published studies, in our series the overall DR of (18)F-CH PET/CT was 58 % and was significantly correlated to trigger PSA. The most important finding of the present study is that ADT does not negatively influence DR of (18)F-CH PET/CT in PC patients with biochemical relapse; therefore, it can be suggested that it is not necessary to withdraw ADT before performing (18)F-CH PET/CT.

Molecular imaging of pulmonary nodules.

OBJECTIVE: Lung nodules can be benign or malignant, reflecting many possible causes, ranging from inflammatory and infectious processes to neoplasms. Incidental detection on chest x-ray or thoracic CT often requires further evaluation by imaging or invasive procedures. CONCLUSION: Currently, 18F-FDG PET/CT offers both anatomic and metabolic characterization of lung nodules. Fluorine-18-thymidine, 11C-methionine, 68Ga-DOTA-somatostatin analogs, and 18F-dihydroxyphenylalanine may offer additional molecular information useful for diagnosis and treatment planning.

The evolution of PET imaging in renal, bladder, upper urinary tract urothelial, testicular and penile carcinoma - Today's impact, tomorrow's potential.

INTRODUCTION: The advancement of hybrid PET/CT or PET/MRI imaging for non-prostate genitourinary cancers has not experienced the rapid progress of prostate cancer. Nevertheless, these neoplasms are aggressive and reliable imaging plays a pivotal role in enhancing patients' quality of life and prognosis. AREAS COVERED: the main evidence regarding [18F]FDG and non-[18F]FDG PET/CT or PET/MRI in non-prostate uro-oncological malignancies are summarized and discussed. Moreover, potential future directions concerning PET imaging in these neoplasms are debated, with the aim to stimulate future research projects covering these fields. EXPERT OPINION: In Renal Cell Carcinoma (RCC), [18F]FDG PET/CT demonstrates varying efficacy in staging, restaging, and prognostic stratification, but PSMA PET/CT is emerging as a potential game-changer, particularly in advanced, high-grade aggressive clear cell RCC. [18F]FDG PET/CT may see an increased use in N and M-staging of bladder cancer, as well as for detecting recurrence and response to neoadjuvant chemotherapy. Preliminary data regarding [68Ga]-FAPI also looks promising in this context. [18F]FDG PET/MRI could be useful for the T-staging of bladder cancer, while upper tract urothelial carcinoma still lacks of molecular imaging literature reports. In testicular and penile cancer [18F]FDG PET/CT has demonstrated its usefulness in several clinical settings, although experiences with non-[18F]FDG radiotracers are lacking.

Role of ¹8F-choline PET/CT in suspicion of relapse following definitive radiotherapy for prostate cancer.

PURPOSE: The aims of the study were (a) to evaluate the diagnostic role, by means of positive detection rate (PDR), of ¹8F-choline (CH) positron emission tomography (PET)/CT in patients with prostate cancer treated with radiotherapy, with curative intent, and suspicion of relapse during follow-up, (b) to correlate the PDR with trigger prostate-specific antigen (PSA), (c) to investigate the possible influence of androgen deprivation therapy (ADT) at the time of scan on PDR and (d) to assess distribution of metastatic spread. METHODS: ¹8F-CH PET/CT exams from 46 consecutive patients (mean age 71.3 years, range 51-84 years) with prostate cancer (mean Gleason score 6.4, range 5-8) previously treated by definitive radiotherapy and with suspicion of relapse with negative or inconclusive conventional imaging were retrospectively evaluated. Of the 46 patients, 12 were treated with brachytherapy and 34 with external beam radiation therapy. Twenty-three patients were under ADT at the time of the examination. Trigger PSA was measured within 1 month before the exam (mean value 6.5 ng/ml, range 1.1-49.4 ng/ml). Patients were subdivided into four groups according to their PSA level: 1.0 < PSA ≤ 2.0 ng/ml (11 patients), 2.0 < PSA ≤ 4.0 ng/ml (16 patients), 4.0 < PSA ≤ 6.0 ng/ml (9 patients) and PSA > 6.0 ng/ml (10 patients). Correlation between ADT and PDR was investigated as well as between PSA and distribution of metastatic spread. RESULTS: The overall PDR of ¹8F-CH PET/CT was 80.4% (37/46 patients), increasing with the increase of trigger PSA. PDR of ¹8F-CH PET/CT is not influenced by ADT (p = 0.710) even if PET performed under ADT demonstrated an overall higher PDR (82.6%). The majority of the patients (59%, 22/37 patients) showed local relapse only, confined to the prostatic bed; 22% of the PET/CT-positive patients (8/37 patients) showed distant relapse only (bone localizations in all of them), while the remaining 19% (7/37 patients) showed both local and distant (lymph node and bone) spread. CONCLUSION: ¹8F-CH PET/CT showed a high overall detection rate (80%), proportional to the trigger PSA (both for local and distant relapse) not influenced by ADT. ¹8F-CH PET/CT is proposed as a first-line imaging procedure in restaging prostate cancer patients primarily treated with radiotherapy.

Fifteen different 18F-FDG PET/CT qualitative and quantitative parameters investigated as pathological response predictors of locally advanced rectal cancer treated by neoadjuvant chemoradiation therapy.

PURPOSE: The aim of this study was to correlate qualitative visual response and various PET quantification factors with the tumour regression grade (TRG) classification of pathological response to neoadjuvant chemoradiotherapy (CRT) proposed by Mandard. METHODS: Included in this retrospective study were 69 consecutive patients with locally advanced rectal cancer (LARC). FDG PET/CT scans were performed at staging and after CRT (mean 6.7 weeks). Tumour SUVmax and its related arithmetic and percentage decrease (response index, RI) were calculated. Qualitative analysis was performed by visual response assessment (VRA), PERCIST 1.0 and response cut-off classification based on a new definition of residual disease. Metabolic tumour volume (MTV) was calculated using a 40 % SUVmax threshold, and the total lesion glycolysis (TLG) both before and after CRT and their arithmetic and percentage change were also calculated. We split the patients into responders (TRG 1 or 2) and nonresponders (TRG 3-5). RESULTS: SUVmax MTV and TLG after CRT, RI, ΔMTV% and ΔTLG% parameters were significantly correlated with pathological treatment response (p < 0.01) with a ROC curve cut-off values of 5.1, 2.1 cm(3), 23.4 cm(3), 61.8 %, 81.4 % and 94.2 %, respectively. SUVmax after CRT had the highest ROC AUC (0.846), with a sensitivity of 86 % and a specificity of 80 %. VRA and response cut-off classification were also significantly predictive of TRG response (VRA with the best accuracy: sensitivity 86 % and specificity 55 %). In contrast, assessment using PERCIST was not significantly correlated with TRG. CONCLUSION: FDG PET/CT can accurately stratify patients with LARC preoperatively, independently of the method chosen to interpret the images. Among many PET parameters, some of which are not immediately obtainable, the most commonly used in clinical practice (SUVmax after CRT and VRA) showed the best accuracy in predicting TRG.

Cavernous Hepatic Hemangioma at 18F-Choline Positron Emission Tomography-Computed Tomography: Be Aware of the Pitfall.

We report a case of a patient performing a positron emission tomography-computed tomography (PET-CT) scan with [18F]F-Choline for biochemical relapse (Prostate specific antigen (PSA) 1.2 ng/ml) of prostate cancer. Two large areas of focal uptake with a cold core within the liver were observed. A contrast-enhanced ultrasound scan performed after the PET scan characterized these lesions as cavernous hepatic hemangiomas, and therefore, a biopsy was not performed; 3 years of follow-up and PET and MRI finding stability confirmed the benignity of their nature.

Renal scintigraphy predicts global cardiovascular risk in hypertensive subjects with normal serum creatinine levels.

BACKGROUND. This cross-sectional study investigates the role of renal scintigraphy on cardiovascular (CV) risk stratification in normoalbuminuric, non-diabetic hypertensive subjects (HTs) free from CV disease and renal dysfunction. METHODS. In 200 HTs aged 55-75 years, glomerular filtration rate (GFR) was measured by technetium-99m-diethylene triamine pentacetic acid clearance during renal scintigraphy. Stage III chronic kidney disease (CKD) was defined as GFR < 60 ml/min/1.73 m(2). For comparing the impact of different methods for CKD diagnosis on CV risk stratification, CKD was also considered as GFR estimated by the Modification of Diet in Renal Disease (MDRD) equation and Cockcroft-Gault's formula. Target organ damage (TOD) was assessed by echocardiography and carotid ultrasonography. Gender-specific odds ratio (OR) with 95% confidence intervals for CKD were derived from a multiple stepwise logistic regression analysis. Global CV risk was stratified according to routine examinations, TOD and CKD. RESULTS. In 38% of cases, an unknown stage III CKD was found. Independent of age, CKD was predicted by history of hypertension (OR = 1.69, p = 0.0001), albuminuria (OR = 1.25, p = 0.0001), smoking (OR = 1.85, p = 0.028) and pulse pressure (OR = 1.21, p = 0.019) in men only. Men had an increased risk of CKD (OR = 2.62, p = 0.002) in comparison with women. Prevalence of TOD was significantly higher only in HTs having CKD diagnosed by renal scintigraphy; TOD and CKD assessment added to classic risk factors modified the CV risk stratification from low-moderate to high and very high. CONCLUSIONS. Renal scintigraphy is an important aid in risk stratification and should be performed in HTs aged >55 years. Pulse pressure was the main blood pressure component that predicted the risk of stage III CKD.

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.

Could genetic analysis be useful in reducing cerebrovascular risk in hypertensive subjects with hyperhomocysteinemia and patent foramen ovale? A 2-year follow-up study.

OBJECTIVES: Potential causes of cryptogenic cerebrovascular (CV) events are patent foramen ovale (PFO) and hyper homocysteinemia (H-Hcys), this latter a well-established risk factor for thrombosis particularly in the presence of mutation for the methylenetetrahydrofolate reductase (MTHFR) gene. This study investigated if in uncomplicated hypertensive subjects (HTs) with isolated PFO and H-Hcys, a different MTHFR polymorphism pattern for C667→T gene mutation could influence PFO management and to reduce the CV risk. METHODS: In thirty-two HTs aged 55.6±14.4years, PFO was diagnosed by echocardiography. MTHFR genotype was evaluated by a multiplex polymerase chain reaction with reverse line blot hybridization assay. In relation to the T allele distribution, HTs were divided in normal (CC), heterozygote (CT) and homozygote (TT) for the MTHFR genotype. All subjects received a supplementation of oral folate (5mg daily) and were evaluated yearly for 2years. Analysis of variance for repeated measures (ANOVA) was used to compare changes of Hcys at baseline and at the end of follow-up and differences between continuous variables were evaluated in the three MTHFR groups with the Tukey's post hoc test after adjustment for confounders. RESULTS: At the follow-up, Hcys levels significantly normalized from baseline both in TT (38.1±6.7 vs. 15±3.6, p<0.01) and CT (26.6±2.3 vs. 9.2±1.6, p<0.01) but not in CC subjects (18.2±1.8 vs. 16.0±1.6, NS). Independently of age, BMI, vitamin treatment both systolic and diastolic blood pressure (BP) significantly decrease at the follow-up in all the MTHFR genotypes. No CV events were observed during the follow-up. CONCLUSIONS: In HTs with isolated PFO and H-Hcys, oral folate supplementation reduces Hcys levels both in TT and CT subjects with C667→T mutation of MTHFR. In addition the BP normalization probably contributed to reduce CV risk in these genotypes.

Reorganization of a Nuclear Medicine Department in Northern Italy During a 2-Month Lockdown for COVID-19 Pandemic.

Coronavirus disease (COVID-19) outbreak has profoundly changed the organization of hospital activities. We present our experience of reorganization of a nuclear medicine service settled in Northern Italy during the pandemic period of March and April 2020 characterized a government-mandated lockdown. Our service remained open during the whole period, performing approximately 80% of the routine practice, while maintaining it COVID-free despite the geographical context characterized by a high risk of infection. Reorganization involved all aspects of a nuclear medicine department, following local, national, and international guidelines for prioritizing patients, telephone and physical triages, deployment of appropriate personal protective equipment, social distancing, and logistic changes for scheduling examinations and disinfection procedures. All staff remained COVID-19-negative despite the unintentional admission of 4 patients who later turned out to be positive for the severe acute respiratory syndrome coronavirus 2. These adopted measures would serve as the basis for safe nuclear medicine services in the post-lockdown phase.

2009 EANM parathyroid guidelines.

The present guidelines were issued by the Parathyroid Task Group of the European Association of Nuclear Medicine. The main focus was imaging of primary hyperparathyroidism. Dual-tracer and single-tracer parathyroid scintigraphy protocols were discussed as well as the various modalities of image acquisition. Primary hyperparathyroidism is an endocrine disorder with high prevalence, typically caused by a solitary parathyroid adenoma, less frequently (about 15%) by multiple parathyroid gland disease (MGD) and rarely (1%) by parathyroid carcinoma. Patients with MGD may have a double adenoma or hyperplasia of three or all four parathyroid glands. Conventional surgery has consisted in routine bilateral neck exploration. The current trend is toward minimally invasive surgery. In this new era, the success of targeted parathyroid surgery depends not only on an experienced surgeon, but also on a sensitive and accurate imaging technique. Recognizing MGD is the major challenge for pre-operative imaging, in order to not direct a patient towards inappropriate minimal surgery. Scintigraphy should also report on thyroid nodules that may cause confusion with a parathyroid adenoma or require concurrent surgical resection. The two main reasons for failed surgery are ectopic glands and undetected MGD. Imaging is mandatory before re-operation, and scintigraphy results should be confirmed with a second imaging technique (usually US for a neck focus, CT or MRI for a mediastinal focus). Hybrid SPECT/CT instruments should be most helpful in this setting. SPECT/CT has a major role for obtaining anatomical details on ectopic foci. However, its use as a routine procedure before target surgery is still investigational. Preliminary data suggest that SPECT/CT has lower sensitivity in the neck area compared to pinhole imaging. Additional radiation to the patient should also be considered. The guidelines also discuss aspects related to radio-guided surgery of hyperparathyroidism and imaging of chronic kidney disease patients with secondary hyperparathyroidism.

68Ga-DOTA-NOC: a new PET tracer for evaluating patients with bronchial carcinoid.

BACKGROUND: Conventional imaging techniques [computed tomography (CT), ultrasound, magnetic resonance] and somatostatin receptor scintigraphy are often insufficient to make a conclusive diagnosis of bronchial carcinoid (BC). PET is commonly used for the assessment of lung cancer but 18F-fluorodeoxyglucose, the most frequently used PET tracer, presents a low sensitivity for the detection of neuroendocrine tumours (NETs). New PET radiopharmaceuticals such as 68Ga-DOTA peptides, which directly bind to somatostatin receptors and are usually expressed on NET cell surfaces, have been reported to be superior to both morphological and somatostatin receptor scintigraphy imaging for gastroenteropancreatic NETs. However, their role in BC has never been evaluated. Our aim is to evaluate the role of 68Ga-DOTA-NOC (68Ga-labelled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-Nal3-octreotide) PET for the assessment of BC patients. METHODS: Ten patients with pathologically proven well-differentiated BC and one patient with highly suggestive CT images for BC were studied by 68Ga-DOTA-NOC PET/CT. PET findings were compared with clinical follow-up, pathology and contrast-enhanced CT findings. RESULTS: 68Ga-DOTA-NOC PET/CT detected at least one lesion in nine of 11 patients and was negative in two. PET/CT and contrast-enhanced CT were discordant in eight of 11 patients, whereas in only three patients both provided similar results. PET/CT detected a higher number of lesions in five patients and excluded malignancy at sites considered positive on CT in three of 11; follow-up confirmed PET/CT findings in all patients. In PET/CT-positive patients, the mean maximal standardized uptake value was 25.9 [4.4-60.5]. On a clinical basis, PET/CT provided additional information in nine of 11 patients leading to the changes in the clinical management of three of nine patients. CONCLUSION: PET/CT with Ga-DOTA-NOC was useful in BC patients because it led to a better evaluation of the extent of the disease.

11C-methionine vs. 18F-FDG PET in soft tissue sarcoma patients treated with neoadjuvant therapy: preliminary results.

OBJECTIVE: In patients with soft tissue sarcoma (STS) the histological response (tumour grade regression: TGR) to neoadjuvant chemoradiotherapy (CRT) may influence the outcome. The main aim of the study was to evaluate the predictive value of 11C-methionine (MET) and 18F-FDG PET/CT in patients with STS treated with neoadjuvant CRT, correlating TGR with SUVmax (standardized uptake value) percentage variation before and after CRT. PATIENTS AND METHODS: Nine patients with STS already scheduled for a neoadjuvant CRT and surgery were enrolled. They underwent MET and FDG PET/CT in a one-day procedure before and after the CRT. Pre-therapy SUVmax and the percentage variation of SUVmax for MET and FDG were correlated with TGR according to the Huvos grade. Grades I-II were considered as partial responders (PR) and grades III-IV as complete responders (CR). RESULTS: FDG pre-treatment mean SUVmax in PR patients was 7.1, while in CR patients it was 13.2. Pre-treatment mean MET SUVmax in PR patients was 75, while in CR patients it was 4.9. The mean percentage variation in FDG SUVmax, was -21.2% in PR patients and -745% in CR patients while that for MET SUVmax was 48% in PR patients and -53.9% in CR patients. CONCLUSION: According to this preliminary study, the percentage variation in FDG before and after CRT seems to discriminate between PR and CR better than MET.

Positron-emission tomography in gynaecologic malignancies.

INTRODUCTION: The role of (18)F-FDG PET in the management of gynaecologic malignancies remains unclear mainly due to the failure of clinicians to appreciate the significance of this imaging tool. However, this under utilisation is being actively re-addressed with a large number of reviews and studies, particularly in the last few years. METHODS AND RESULTS: PET has been shown to have high sensitivity and specificity in the evaluation of relapse and nodal disease in cervical cancer, while other uses such as staging and monitoring response to therapies being under further investigation. Similarly, promising results have been published in the use of PET in patients affected by endometrial cancer and uterine sarcomas for detecting lymph nodes metastasis and recurrent disease. In ovarian cancer, PET appears to have a great potential in staging and assessment of disease relapse. An important utility of PET in gynaecologic tumours, which is shared with a large number of other malignancies, is its value in positively changing the patients' management. CONCLUSION: The surge in studies using PET in gynaecological malignancies is in its early stages, and further studies are required to optimise the role of PET in these conditions.

Functional nuclear medicine imaging of medullary thyroid cancer.

Medullary thyroid cancer (MTC) originates from parafollicular C cells of the thyroid and accounts for 3-12% of all thyroid cancers. As opposed to other types of dedifferentiated thyroid tumours, MTC cells are highly functional, producing and secreting high amounts of calcitonin and carcinoembryonic antigen. As parafollicular C cells are of neural crest origin, MTC acts as a neuroendocrine tumour also and expresses somatostatin receptors. Although conventional radiological methods such as ultrasonography, computed tomography and magnetic resonance imaging are widely used in the primary diagnosis and staging, they often fail to localize the residual or recurrent disease because the majority of MTC recurrence presents as occult disease. Thus, owing to functional characteristics of MTC, functional imaging modalities of nuclear medicine play a major role in the diagnostic and therapeutic strategies for MTC. Among nuclear medicine modalities, Tc(V) -dimercaptosuccinic acid, In-octreotide and I/I-meta-iodobenzylguanidine are commonly used in the diagnostic and even more in postoperative work-up of MTC. Alternatively, F-fluorodeoxyglucose and other positron emission tomography radiopharmaceuticals such as F-fluorodopa or F-fluorodopamine as well as radiolabelled antibodies such as Tc/I/I anticarcinoembryonic antigen, antigastrin, and anticholecystokinin-B have promising results. Functional imaging has a great advantage for nuclear medicine techniques in the routine work-up of MTC patients and also has a wide use in experimental studies.

Clinical significance of axillary findings in patients with lymphoma during follow-up with 18F-fluorodeoxyglucose-PET.

PURPOSE: The aim of this study was to evaluate the clinical significance of positive axillary findings in patients with Hodgkin's disease and non-Hodgkin's lymphoma during follow-up with 18F-fluorodeoxyglucose-PET. MATERIALS AND METHODS: We retrospectively reviewed PET scans carried out in 543 patients during follow-up. Patients with reports describing any increased fluorodeoxyglucose uptake at the axillary level were selected (106 cases) and final assessment of the findings was available in 78 patients (17 Hodgkin's disease, 51 non-Hodgkin's lymphoma). PET scans were performed after standard procedure and reports were interpreted as positive or negative on the basis of visual analysis. At the moment of the scan all patients had no clinical or laboratory sign of relapse, and had not received therapy for at least 6 months. All PET results were compared with other diagnostic procedures (ultrasonography and computed tomography), biopsy and/or follow-up data. RESULTS: Of 78 patients, 24 were PET positive in one axilla, 23 had axillary findings and one or more other extra axillary sites, five patients were positive in both axillas and 26 were positive in both axillas and one or more other sites. Of the 24 patients with single axillary finding, the result for five was true positive and for 19 it was false positive. Sixteen cases of the 23 patients with PET positive at one axilla and other sites had a true positive result, whereas seven had a false positive result. Only one of five patients with both axillas being positive at PET turned out to be true positive; finally, 23 cases from the 26 patients with both axillas and other findings had a true positive result and three of 26 had a false positive result. Overall, 45 out of 78 patients were true positive and 33 were false positive. CONCLUSION: Axillary findings are relatively frequent and can be isolated or in association with other findings. In patients with axillary involvement only the frequency of false positivity results is elevated and therefore these cases need to be evaluated carefully. In contrast, axillary findings associated with other pathological localizations show true positive results in most cases, thus indicating a high likelihood of disease recurrence. Standardized uptake values showed a limited role for discriminating true-positive and false-positive findings.

Antigranulocyte scintigraphy in infected hip prosthesis: the diagnostic importance of delayed 20-24-h imaging and semiquantitative analysis.

AIM: To evaluate clinical efficacy of a dual-time acquisition protocol, which included 4 and 20/24-h imaging with antigranulocyte antibody scintigraphy (LeukoScan) combined with semiquantitative analysis in the diagnosis of infection in painful hip prosthesis. METHODS: Sixty-seven consecutive patients with hip prosthesis were enrolled in this research project: 35 females, 32 males, mean age of 56.3 years. All patients had clinical and biochemical suspicious of infection. Each prosthesis had been implanted 3 months to 12 years before enrollment in this study. Twenty-four patients were on antibiotic therapy at the time of scintigraphy. Seven patients had bilateral hip prosthesis, one painful and the other painless: the seven painless prostheses were considered controls. LeukoScan examination was performed both at early (4 h) and delayed (20/24 h) times. The scintigraphic data were assessed both by visual and semiquantitative methods by three experienced nuclear medicine physicians blinded to clinical, laboratory and radiographic results. The uptake was graded visually by a 4-point scale: intense=3, moderate=2, mild=1 and absent=0. The semiquantitative analysis was obtained by a region of interest (ROI) analysis used in the anterior views to measure the ratio between the mean radioactivity in the prosthesis and the background radioactivity in the early and delayed images. An increase in the intensity of uptake of at least one scale-step at visual analysis and 20% at semiquantitative ROI analysis at the dual-time (early vs. delayed) LeukoScan was considered consistent with infection, whereas a stable or decreasing pattern was judged a negative result. Three-phase 99mTc-hydroxymethane diphosphonate bone scan was also performed routinely. Final diagnosis was determined at surgery and/or long-term clinical and imaging follow-up. RESULTS: At visual analysis, sensitivity for both early and delayed imaging was 94%, whereas specificity was 71% for early imaging and 83% for early and delayed imaging approach. At semiquantitative ROI analysis, sensitivity remained 94%, whereas specificity rose slightly to 73% for early imaging and to 90% for early and delayed imaging combined. Of note, four false-positive early scans were diagnosed correctly as negative on delayed imaging showing a decreasing pattern in uptake intensity. Sensitivity and specificity were similar whether patients were on or off antibiotic therapy. CONCLUSION: Our data show that early imaging LeukoScan is highly sensitive in evaluating septic prosthesis, but it is not optimally specific. Although the dual-time LeukoScan is capable of significantly increasing specificity for detecting infection. The semiquantitative ROI analysis further increased the specificity. Concomitant antibiotic treatment did not seem to influence the diagnostic efficacy of LeukoScan scintigraphy in detecting infected hip prosthesis.

18F-FDG PET/CT in myeloma with presumed solitary plasmocytoma of bone.

AIM: To evaluate the value of 18F-fluorodeoxy-glucose (FDG) positron emission tomography with computed tomography (PET/CT) in myeloma in patients presenting with a solitary plasmacytoma of bone (SPB). PATIENTS AND METHODS: Fourteen consecutive patients studied since 2006, all having a diagnosis of SPB before PET/CT imaging took part in this study. In 3 patients PET/CT was performed for staging while in the remaining 11 it was used to monitor therapy. PET/CT was performed using a dedicated tomograph 60-90 minutes after intravenous injection of 53 MBq/kg of 18F-FDG and the results were compared to other diagnostic procedures [radiographs and magnetic resonance imaging (MRI)], biopsy, and other available follow-up data. RESULTS: In 8/14 patients, PET/CT scans showed previously unsuspected sites of increased FDG accumulation. In 6/8 patients, FDG uptake was considered pathologic, depicting myeloma involvement in bone, while in the remaining cases, findings were considered incidental and not related to myeloma. PET findings attributed to myeloma were confirmed (i.e. true positives) in 6/6 cases (100%) and in all patients with findings reported as non-pathologic, myeloma was excluded (100% true negatives). CONCLUSION: Our preliminary data in a small number of cases suggests that there are a group of patients with SPB (local disease) in whom FDG PET/CT may detect other unsuspected sites of bone involvement, upstaging the extent of the disease. In these cases, SPB may be a local manifestation of multiple myeloma where other sites of involvement have eluded detection by other less sensitive imaging modalities (i.e. skeletal surveys) or anatomically restricted imaging (i.e., less than total body MR or CT). Finding other sites of involvement have significant implications for appropriate treatment of myeloma.