A need for eye lens dosimetry in nuclear medicine

Background: Changing the individual dose limit for the lens of the eye from a value of 150 mSv per year to a level of 20 mSv (averaged over defined periods of five years or 50 mSv in a single year) means that issues related to routine eye lens dosimetry become interesting from the point of view of radiation protection. This could mean that the dosimeter designed to measure the doses at the level of the eye lens may become the next dosimeter routinely worn by nuclear medicine workers occupationally exposed to ionising radiation. The dosimeters currently used in nuclear medicine are the personal dosimeter and the ring dosimeter. Will this also be the case for nuclear medicine employees? In this interdisciplinary branch of medicine, the factors that cause the highest risk of radiation exposure of personnel are the process of manual handling, i.e. the process of preparing a radiopharmaceutical called labelling. Most of the radiopharmaceuticals used in nuclear medicine are labelled manually. In Poland, the exception from this rule is when radiopharmaceuticals are produced for the needs of positron emission tomography (PET), which are labelled using automatic processes. Manual procedures also include the process of radiopharmaceutical injection to the patients. The aim of the work was to assess the exposure of eye lenses of workers in nuclear medicine, as well as of the personnel in centers that produce radiopharmaceuticals for PET diagnostics, from the viewpoint of advisability of routine eye lens exposure monitoring, taking into account changes in the dose limit for the lens of the eye. Methods: The results of own measurements of the personal dose equivalent Hp(3), carried out in five nuclear medicine departments in Poland, as well as in two centers producing radiopharmaceuticals for PET, were subject to analysis. The analysis includes two most frequently used radionuclides for diagnostic purposes, namely 99mTc, 18F and the less frequently used 68Ga, in addition to 131I, which is used for therapeutic purposes. Dosimetric measurements were made using thermoluminescent detectors of domestic manufacture. Results & Conclusions: Estimated analysis of the annual exposure makes it possible to indicate cases where the maximum annual value of personal dose equivalent, in terms of Hp(3), exceeds threefold the new limit value specified at 20 mSv/year

Highlights lecture EANM 2015: the search for nuclear medicine’s superheroes

The EANM 2015 Annual Congress, held from October 10th to 14th in Hamburg, Germany, was outstanding in many respects. With 5550 participants, this was by far the largest European congress concerning nuclear medicine. More than 1750 scientific presentations were submitted, with more than 250 abstracts from young scientists, indicating that the future success of our discipline is fuelled by a high number of young individuals becoming involved in a multitude of scientific activities. Significant improvements have been made in molecular imaging of cancer, particularly in prostate cancer. PSMA-directed PET/CT appears to become a new gold standard for staging and restaging purposes. Novel tumour specific compounds have shown their potential for target identification also in other solid neoplasms and further our understanding of tumour biology and heterogeneity. In addition, a variety of nuclear imaging techniques guiding surgical interventions have been introduced. A particular focus of the congress was put on targeted, radionuclide based therapies. Novel theranostic concepts addressing also tumour entities with high incidence rates such as prostate cancer, melanoma, and lymphoma, have shown effective anti-tumour activity. Strategies have been presented to improve further already established therapeutic regimens such as somatostatin receptor based radio receptor therapy for treating advanced neuroendocrine tumours. Significant contributions were presented also in the neurosciences track. An increasing number of target structures of high interest in neurology and psychiatry are now available for PET and SPECT imaging, facilitating specific imaging of different subtypes of dementia and movement disorders as well as neuroinflammation. Major contributions in the cardiovascular track focused on further optimization of cardiac perfusion imaging by reducing radiation exposure, reducing scanning time, and improving motion correction. Besides coronary artery disease, many contributions focused on cardiac inflammation, cardiac sarcoidosis, and specific imaging of large vessel vasculitis. The physics and instrumentation track included many highlights such as novel, high resolution scanners. The most noteworthy news and developments of this meeting were summarized in the highlights lecture. Only 55 scientific contributions were mentioned, and hence they represent only a brief summary, which is outlined in this article. For a more detailed view, all presentations can be accessed by the online version of the European Journal of Nuclear Medicine and Molecular Imaging (Volume 42, Supplement 1)

Related to Anxiety: Arbitrarily Applicable Relational Responding and Experimental Psychopathology Research on Fear and Avoidance

Humans have an unparalleled ability to engage in arbitrarily applicable relational responding (AARR). One of the consequences of this ability to spontaneously combine and relate events from the past, present, and future may, in fact, be a propensity to suffer. For instance, maladaptive fear and avoidance of remote or derived threats may actually perpetuate anxiety. In this narrative review, we consider contemporary AARR research on fear and avoidance as it relates to anxiety. We first describe laboratory-based research on the emergent spread of fear- and avoidance-eliciting functions in humans. Next, we consider the validity of AARR research on fear and avoidance and address the therapeutic implications of the work. Finally, we outline challenges and opportunities for a greater synthesis between behavior analysis research on AARR and experimental psychopathology

Application of optical topography in non-invasive study of brain blood perfusion and its preliminary verification by SPECT technique

Obserwacja zjawiska napływu i klirensu dożylnych środków kontrastujących jest techniką często stosowaną w diagnostyce medycznej. Zastosowanie w tym celu barwników, których widmo absorpcyjne leży w zakresie bliskiej podczerwieni, może być wykorzystane do badań hemodynamiki mózgu metodą optyczną. Opublikowane w ostatnich latach wyniki badań potwierdzają, że cyrkulacja barwnika ICG (zieleń indocjaninowa) w tkance mózgowej może być wykryta bezinwazyjnie metodą optyczną. W niniejszej pracy zostały przedstawione wstępne wyniki badań uzyskane z wykorzystaniem wielokanałowego sytemu do czasowo rozdzielczych pomiarów optycznych, skonstruowanego w IBIB PAN. Badania z zastosowaniem środka kontrastującego ICG przeprowadzono u osób zdrowych i w grupie pacjentów ze stwierdzonymi średnimi dolegliwościami neurologicznymi. Badania porównawcze zostały wykonane metodą radioizotopową SPECT używaną rutynowo w badaniach ukrwienia mózgu.Monitoring of inflow and washout of an exogenous contrast agent circulating in the human body is frequently utilized for medical diagnosis. Injection of a absorbing dye in near infrared wavelength region can be applied for estimation of cerebral blood flow or perfusion using optical method. It was reported that ICG (indocyanine green) circulating in the brain can be detected non-invasively on the surface of the human adult head. In the present paper we show results of analysis of time-resolved optical signals measured with the use of the self-constructed brain imager based on previously reported brain oxygenation topography system. The study were curried out on healthy volunteers and patients with mild cerebrovascular disorders after injections of the ICG contrast agent. Obtained results from optical measurements were compared with routinely used SPECT technique

Emotionally negative stimuli can overcome attentional deficits in patients with visuo-spatial hemineglect.

Left unilateral spatial neglect resulting from right brain damage is characterized by loss of awareness for stimuli in the contralesional side of space, despite intact visual pathways. We examined using fMRI whether patients with neglect are more likely to consciously detect in the neglected hemifield, emotionally negative complex scenes rather than visually similar neutral pictures and if so, what neural mechanisms mediate this effect. Photographs of emotional and neutral scenes taken from the IAPS were presented in a divided visual field paradigm. As expected, the detection rate for emotional stimuli presented in the neglected field was higher than for neutral ones. Successful detection of emotional scenes as opposed to neutral stimuli in the left visual field (LVF) produced activations in the parahippocampal and anterior cingulate areas in the right hemisphere. Detection of emotional stimuli presented in the intact right visual field (RVF) activated a distributed network of structures in the left hemisphere, including anterior and posterior cingulate cortex, insula, as well as visual striate and extrastriate areas. LVF-RVF contrasts for emotional stimuli revealed activations in right and left attention related prefrontal areas whereas RVF-LVF comparison showed activations in the posterior cingulate and extrastriate visual cortex in the left hemisphere. An additional analysis contrasting detected vs. undetected emotional LVF stimuli showed involvement of left anterior cingulate, right frontal and extrastriate areas. We hypothesize that beneficial role of emotion in overcoming neglect is achieved by activation of frontal and limbic lobe networks, which provide a privileged access of emotional stimuli to attention by top-down modulation of processing in the higher-order extrastriate visual areas. Our results point to the importance of top-down regulatory role of the frontal attentional systems, which might enhance visual activations and lead to greater salience of emotional stimuli for perceptual awareness

Zastosowanie metod medycyny nuklearnej w diabetologii

Cukrzyca jest chorobą wieloukładową, charakteryzującą się niedoborem insuliny lub opornością tkanek na działanie insuliny, które prowadzą do stanów hiperglikemii. W przebiegu długotrwałej cukrzycy dochodzi do upośledzenia licznych funkcji organizmu oraz uszkodzenia narządów na skutek mikro- i makroangiopatii. Proces ten ma charakter postępujący i wieloletni. Patologiczne zmiany na poziomie mikroskopowym zaczynają się kilka miesięcy lub nawet kilka lat przed kliniczną manifestacją choroby. W tym okresie diagnostyka tego typu zaburzeń przy użyciu klasycznych metod obrazowania jest niezwykle trudna, a czasem niemożliwa. Metody radioizotopowe, obrazując procesy zachodzące na poziomie komórkowym, pozwalają na bardzo wczesną diagnostykę procesów chorobowych występujących w przebiegu cukrzycy