Renogram in Nuclear Medicine is the main examination for the diagnosis of several diseases in children such as kidney failure or obstructive uropathy. The dosimetry of this examination is based on the group-specific values presented by the ICRP publications. The need for person-specific dosimetry in the Nuclear Medicine urged in the creation of a new image-based dosimetric method, based on the outcome of the examination of the renogram of each patient. With the help of an experimental procedure, the percentage of self-absorption inside the “source” organs and the absorption from the surrounding tissues of the transmitted radiation of the radiopharmaceutical (99m-Tc-MAG3) is calculated, leading with the use of the MIRD method, to the measurement of the activity of Technetium inside the patient’s organs during the renogram’s duration. Afterwards with the help of theoretical models, conclusions and assumptions the total cumulated activity of the patient’s organs is calculated. The results show similar values with other projects published, which were more invasive and less cost-effective for the department. / Στην πυρηνική ιατρική, τα νεφρογράμματα είναι η κύρια εξέταση για την διάγνωση ασθενειών στα παιδιά, όπως η νεφρική ανεπάρκεια και η ουροφρακτική ανεπάρκεια. Η δοσιμετρία αυτών των εξετάσεων στηρίζεται πάνω στα group-specific όρια του ICRP. Η ανάγκη για person-specific δοσιμετρία και στην Πυρηνική Ιατρική ώθησε στη δημιουργία μιας δοσιμετρικής μελέτης που στηρίζεται στην εικόνα (image-based) από το αποτέλεσμα της εξέτασης του νεφρογράμματος του κάθε ασθενή. Με τη βοήθεια μιας πειραματικής διάταξης υπολογίζεται το ποσοστό αυτο-απορρόφησης στα όργανα «στόχους» και το ποσοστό απορρόφησης της εκπεμπόμενης ακτινοβολίας από τους περιβάλλοντες ιστούς, οδηγώντας μαζί με την μέθοδο του MIRD, στον υπολογισμό της ενεργότητας του ραδιοφαρμάκου (99m-Tc-MAG3) μέσα στα όργανα του ασθενή καθ’ όλη την διάρκεια της εξέτασης. Με την βοήθεια θεωρητικών μοντέλων, συμπερασμάτων και υποθέσεων υπολογίζεται η συνολική ακτινική επιβάρυνση του ασθενούς και τα αποτελέσματα δίνουν παραπλήσιες τιμές με άλλες δημοσιευμένες εργασίες, που ακολούθησαν πιο επεμβατικές ή πιο κοστοβόρες για το τμήμα, μεθόδους.

Understanding temporal relations among posttraumatic stress disorder (PTSD) symptom dimensions has received increasing attention in research. However, current findings in this area are limited by group-level approaches, which are based on inter-individual variation. PTSD is a heterogeneous syndrome and symptoms are likely to vary across individuals and time. Thus, it is important to examine temporal relations among PTSD symptom dimensions as dynamic processes and at the level of intra-individual variation. The aim of the present study was to capture temporal dynamics among PTSD symptom dimensions at an individual level using unified structural equation modeling (uSEM). World Trade Center (WTC) 9/11 responders (N = 202) oversampled for current PTSD (18.3% met criteria in past month) were recruited from the Long Island site of the WTC health program. Using ecological momentary assessment (EMA), PTSD symptoms were assessed three times a day over seven consecutive days. The person-specific temporal relations among PTSD symptom dimensions were estimated with individual-level uSEM. For the sample as a whole, hyperarousal played a key role in driving the other three symptom dimensions longitudinally, with the strongest effect in intrusive symptoms. However, daily temporal relations among PTSD symptoms were idiosyncratic. Although hyperarousal was a strong predictor of subsequent symptom severity, only 33.95% of the sample showed this predictive effect while others showed more evident temporal relations between intrusion and avoidance. Implications for personalized health care and recommendations for future research using individual-level uSEM in psychopathology are discussed.