Evaluation of different counting methods for use in radiochemical purity testing procedures for (99m)Tc-labelled radiopharmaceuticals

The efficiency and accuracy of different methods for quality control of radiopharmaceutical preparations for diagnostic purpose were studied. The radiochemical purity of 99mTc Tetrafosmin, 99mTc Exametazime, 99mTc Sestamibi and 99mTc Oxidronate was evaluated by different thin layer chromatography systems, followed by cutting of the strips into two or three sections and by the measurement of radioactivity distribution by dose calibrator or gamma counter. In addition, to confirm the accuracy of these routine procedures, the strips were cut into a number of micro-sections (14–25) and each of them evaluated by the gamma counter. The three tested procedures gave similar results and revealed a good and comparable accuracy. The radioactivity measurement with the dose calibrator remains the most practicable because of the rapidity of execution

Soft gluons away from jets: distribution and correlation

Recently, an exact conformal mapping between soft gluons emitted from jets at large angle in e+e- annihilation and those in the BFKL evolution of a high energy hadron has been proposed. We elucidate some remarkable aspects of this correspondence and use them to analytically compute the distribution and correlation of gluons in the interjet region. We also establish the timelike counterpart of Mueller's dipole model and discuss the resulting linear and nonlinear evolution equations.Comment: 25 pages, v2: minor corrections, to be published in jhe

Conformal collider physics: Energy and charge correlations

We study observables in a conformal field theory which are very closely related to the ones used to describe hadronic events at colliders. We focus on the correlation functions of the energies deposited on calorimeters placed at a large distance from the collision. We consider initial states produced by an operator insertion and we study some general properties of the energy correlation functions for conformal field theories. We argue that the small angle singularities of energy correlation functions are controlled by the twist of non-local light-ray operators with a definite spin. We relate the charge two point function to a particular moment of the parton distribution functions appearing in deep inelastic scattering. The one point energy correlation functions are characterized by a few numbers. For ${\cal N}=1$ superconformal theories the one point function for states created by the R-current or the stress tensor are determined by the two parameters $a$ and $c$ characterizing the conformal anomaly. Demanding that the measured energies are positive we get bounds on $a/c$. We also give a prescription for computing the energy and charge correlation functions in theories that have a gravity dual. The prescription amounts to probing the falling string state as it crosses the $AdS$ horizon with gravitational shock waves. In the leading, two derivative, gravity approximation the energy is uniformly distributed on the sphere at infinity, with no fluctuations. We compute the stringy corrections and we show that they lead to small, non-gaussian, fluctuations in the energy distribution. Corrections to the one point functions or antenna patterns are related to higher derivative corrections in the bulk.Comment: 73 pages, 8 figures; v2: minor changes and added references; v3: more references adde

Liver metastases on serial contrast-enhanced multidetector computed tomography examinations: was the detection possible on previous examinations?

OBJECTIVE: To verify the earliest detectability of liver metastases in patients who underwent serial multidetector computed tomography (MDCT) examinations. METHODS: We selected 12 patients with known primary cancer who underwent 4 or more contrast-enhanced, 4-detector MDCTs. When metastases had been reported, an evaluation of the preceding MDCT was done to define whether the lesion was detectable, detectable only by minimal signs, undetectable, or detected but misdiagnosed as a benign lesion (MBL). RESULTS: Eighty-eight lesions were analyzed. Evaluating the preceding examination, we defined detectable (n= 8), detectable only by minimal signs (n= 5), undetectable (n= 74), and MBL (n= 1). The group with minimal signs was composed of 4 small hypodense foci and 1 calcification. The MBL was a non-Hodgkin lesion first misdiagnosed as a hemangioma. CONCLUSION: Approximately 15% of liver metastases were prospectively missed, 9% of them being retrospectively detectable, 6% being retrospectively visible as minimal signs, whereas only 1% of liver metastases were misdiagnosed as a benign lesion. Copyright (copyright) 2006 by Lippincott Williams & Wilkins

Low-fat angiomyolipoma of the liver studied with contrast-enhanced ultrasound and multidetector computed tomography.

We report the case of a 30-year-old woman with persistent pain at the right hypochondrium, relapsing fever, and normal serum tests. Ultrasound showed a hyperechoic inhomogeneous mass; following sulfur hexafluoride injection, uniform enhancement at 14-16s and rapid wash-out at 26s was found. Multidetector computed tomography showed an inhomogeneously hypodense mass, with no detectable negative density values, characterized by inhomogeneous enhancement at the arterial phase and wash-out at the portal phase. Histopathology demonstrated a hepithelioid angiomyolipoma with a poor fatty component. This diagnosis should always be considered in the presence of a very rapid wash-out after intravenous contrast injection. However, a hepatocellular carcinoma cannot be excluded and the final diagnosis of low-fat angiomyolipoma must be pathologically proved based on immunohistochemistry

Salivary glands imaging

La diagnostica per immagini per le ghiandole salivari pu\uf2 avvalersi di diverse modalit\ue0, quali l\u2019ecografia (ultrasonography, US), la tomografia computerizzata (TC), la risonanza magnetica (RM), la sialografia e la scintigrafia. L\u2019obiettivo di questa review \ue8 quello di illustrare il ruolo della diagnostica per immagini nella valutazione delle patologie a carico delle ghiandole salivari. La US rappresenta solitamente l\u2019indagine di prima scelta nelle sospette sialolitiasi. Come seconda scelta pu\uf2 anche essere utilizzata la TC, che ha un\u2019elevata accuratezza nel rilevare la presenza di calcoli e che permette di distinguere pi\uf9 accuratamente, rispetto alla US, i calcoli multipli da un unico calcolo di grandi dimensioni. La TC \ue8 anche importante per valutare la presenza di masse a livello delle ghiandole salivari , associate a processi di tipo ostruttivo o infiammatorio. Negli altri casi la RM rappresenta l\u2019indagine di scelta, dal momento che \ue8 la tecnica pi\uf9 affidabile per dimostrare la presenza di un\u2019invasione perinervosa, meningea e a livello della base del cranio. La sialografia convenzionale \ue8 utile per studiare le infezioni croniche, i tumori e i calcoli, ma \ue8 una tecnica invasiva gravata da inconvenienti e da complicanze. La scintigrafia ha potenzialmente la capacit\ue0 di fornire simultaneamente informazioni di tipo morfologico e funzionale, di conseguenza le sue indicazioni cliniche principali sono rappresentate dalla valutazione della funzionalit\ue0 delle ghiandole salivari e dell\u2019escrezione della saliva in caso di patologie autoimmunitarie o dopo irradiazione dei distretti cefalici e del collo. Questa tecnica di diagnostica per immagini pu\uf2 anche essere di aiuto per la diagnosi del tumore di Warthin, ed \ue8 specialmente utile nel paziente pi\uf9 anziano con controindicazioni chirurgiche o nei pazienti con masse parotidee multipleSeveral modalities are available for salivary gland imaging, such as ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), sialography and scintigraphy. The aim of this review was to illustrate the role of imaging in evaluating salivary gland diseases. US is usually the first-line technique in suspected sialolithiasis. Secondly, also CT may be used. It has demonstrated a high accuracy in detecting the presence of calculi and it is more accurate than US in distinguishing multiple clusters of stones from single large stone. CT is also important in the evaluation of salivary glands masses associated with obstructive or inflammatory process; in the other cases MRI is the technique of choice, as it allows to better detect perineural, meningeal and skull base invasion. Conventional sialography is useful in case of chronic infections, tumours and calculi but is an invasive technique burdened by drawbacks and complications. To obtain simultaneously morphologic and functional information scintigraphy is a solution: its main clinical indications consist in evaluation of salivary glands function and salivary excretion in autoimmune disease or after irradiation of head and neck district. This imaging method may also help to diagnose Warthin's tumour and it is especially useful in elderly patients with surgical contain- dications or in oatients with multinle carotid masses

Common carotid artery pseudoaneurysm after neck dissection : colour Doppler ultrasound and multidetector computed tomography findings

Common carotid artery pseudoaneurysm is a rare disease, which has been previously unreported in association with neck dissection. We describe the Doppler ultrasound and multidetector computed tomography (CT) findings of a case of carotid pseudoaneurysm, one month after pharyngolaryngectomy with bilateral neck dissection. Multidetector CT confirmed the diagnosis made on the basis of Doppler ultrasound; the high image quality of axial and three-dimensional reconstructions avoided the need for pre-operative conventional angiography. In the presence of a pulsatile cervical mass after neck surgery, pseudoaneurysm of the carotid artery should be included in the differential diagnosis, and multidetector CT can be the sole pre-operative diagnostic imaging modality

Safety of unprotected carotid artery stent placement in symptomatic and asymptomatic patients : a retrospective analysis of 30-day combined adverse outcomes

PURPOSE: To retrospectively evaluate the outcome of carotid artery stent placement (CAS) without the use of embolic protection devices (EPDs) in a large cohort of patients. MATERIALS AND METHODS: Institutional review board approval and informed consent from all patients were obtained. Preprocedure color Doppler ultrasonography (US), magnetic resonance (MR) imaging, or computed tomography (CT) were used to evaluate stenosis severity (70% or greater). Clinical findings and combined 30-day complication rates in 400 patients (289 men, 111 women; mean age, 73 years +/- 8 [standard deviation]) who underwent unprotected CAS for asymptomatic (n = 156; 39%) or symptomatic (n = 244, 61%) stenoses were analyzed. Follow-up at 30 days included neurologic evaluation and color Doppler US. RESULTS: Self-expanding stents were successfully deployed in 397 of 400 (99.25%) patients. Among the 397 patients, nine (2.27%) major complications (all in patients with prior symptoms) had occurred at 30 days, including three (0.76%) major (all in patients who had stopped antiplatelet prophylaxis) and six (1.5%) minor strokes--three intraprocedural and three delayed. Minor complications included 16 (4%) transient ischemic attacks, four in asymptomatic and 12 in symptomatic patients. The 30-day combined adverse outcomes (transient ischemic attack, ipsilateral stroke, death) were significantly correlated with prior presence of symptoms (symptomatic, 8.6%; asymptomatic, 2.6%; P < .03). CONCLUSION: Stent placement without EPD was performed with a high technical success rate. For asymptomatic patients, the combined 30-day adverse-outcomes rate was within the limits recommended by the American Heart Association for carotid endarterectomy and compared favorably with results reported for CAS with EPD. When a transient ischemic attack is excluded, the 30-day combined death and stroke rate among patients with prior symptoms also compared favorably with published results