Twelve decades of using radium in the treatment of deeper localised cancers

The end of the 19th and the beginning of the 20th century marked a period of fundamental discoveries in the physics of ionising radiation (X radiation and radioactivity). Isolating radium, a highly radioactive element, immediately opened the way to its application for medical therapeutic purposes. It turned out that the sources of ionising radiation are very effective for changes localised on the skin and at small depths under the skin but not for lesions at greater depths. Interestingly, the inventor of the modern telephone, Alexander Graham Bell, was the first to come up with the idea of placing radium sources in glass tubes and placing them directly in the pathologically changed tissues of the patients to be treated (at greater depths). That period marked the beginning of a highly successful era in radium therapy, involving the use of capsules and needles filled with radium, which eventually led to the development of modern brachytherapy. Unfortunately, for several decades people believed in the universally therapeutic properties of radium, so that (fortunately in smaller quantities) it was added to water, food, hygiene products, etc

Computed tomography simulator conversion curve dependence on scan parameters and phantom dimension

Introduction: Using computed tomography (CT) and treatment planning systems (TPS) in radiotherapy, due to the difference in photon beam energy on CT and linear accelerator, it is necessary to convert Hounsfield units (HU) to relative electron density (RED) values. The aim of this dosimetric study was to determine whether there is a significant effect of potential in the CT tube, field of view size (FOV), and phantom dimensions on the CT conversion curve CT-RED. The second aim is whether there are significant differences between the CT-RED obtained by the Computerized Imaging Reference Systems (CIRS) Thorax 002LFC phantom and the “reference” curve in the TPS, obtained by the CIRS 062M pelvis phantom, at the same CT conditions.Methods: Heterogeneous CIRS 062M and CIRS Thorax 002LFC phantoms were used, which anatomically and dimensionally represent the human pelvis, head, and thorax, with a set of known RED inserts. They were scanned on a CT LightSpeed GE simulator and obtained CT-RED.Results: The high voltage in the CT tube had a significant effect on the HU (t = 10.72, p < 0.001) for RED values >1.1, while FOV as a parameter did not show statistical significance for the 062M pelvis phantom. Comparing the slopes (062M pelvis and head) of the CT-RED for RED ≥ 1.1, the obtained value is t = 1.404 (p = 0.163). In the case of a 062M pelvis and a 002LFC phantom, we have seen a difference in RED values (for the same HU value) of 5 % in the RED region ≥ 1.1 (bone).Conclusion: Patients should be imaged on a CT simulator only at the potential of the CT tube on which the conversion curve was recorded. The influence of the FOV and scanned phantom dimensions is not statistically significant on the appearance of the calibration curve (RED ≥ 1.1)

Izloženost osoblja nuklearne medicine ionizirajućem zračenju u 18F-FDG PET/CT dijagnostici – preliminarna retrospektivna studija

This retrospective study provides an insight into the levels of radiation exposure of six nuclear medicine (NM) staff (four technologists and two nurses) performing routine diagnostic 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) at the University Clinical Centre of the Republic of Srpska, Department of Nuclear Medicine and Thyroid Disorders, Banja Luka, Bosnia and Herzegovina. Data analysis included monthly staff exposure measured with personal thermoluminescent dosimeters (TLD) between June and December 2018, quantified in terms of normalised dose for the whole body [Hp(10)] and dominant hand [Hp(0.07)] and their comparison between each staff member and between the two groups (technologists and nurses). The study goal was to establish how our Department compared with reports from other PET/CT centres worldwide in terms of annual number of procedures and exposure limits and whether there could be room for further improvements in radiation protection. The number of procedures rose considerably from 208 in 2016 to 876 in 2019 and was 423 in the observed seven-month period. Mean individual wholebody exposure dose per GBq of injected 18F-FDG activity, [Hp(10)/A] was 18.55 μSv/GBq for the four technologists and 15.61 μSv/GBq for the two nurses. Mean dominant-hand exposure dose per GBq of injected 18F-FDG activity [Hp(0.07)/A] was 16.99 μSv/GBq and 25.44 μSv/GBq for the two groups, respectively. The average annual cumulative dose for all staff was (1.06±0.29) mSv for Hp(10) and (1.15±0.32) mSv for Hp(0.07). These results are comparable with those of similar studies. Staff doses were well below the annual limits. Nurses received slightly higher extremity doses than technologists. In view of the increasing trends in the number of PET/CT procedures, dose monitoring should be continued to identify exposure hotspots and maintain doses as low as possible.Ova retrospektivna studija pruža uvid u razinu izloženosti ionizirajućem zračenju za šestero zaposlenih (četiri radiološka tehničara i dvije medicinske sestre) koji izvode rutinska dijagnostička ispitivanja primjenom 18F-FDG na PET/CT-u u Kliničkom zavodu za nuklearnu medicinu i bolesti štitne žlijezde Univerzitetskoga kliničkog centra Republike Srpske (Banja Luka, Bosna i Hercegovina). Analiza podataka obuhvatila je mjesečnu izloženost osoblja, koja je od lipnja do prosinca 2018. mjerena osobnim termoluminiscentnim dozimetrima (TLD-ima), a izražena je normaliziranom dozom za cijelo tijelo [Hp(10)] te dozom za dominantnu ruku [Hp(0,07)]. Također, u obzir je uzeta i usporedba tih veličina između svakoga člana osoblja te između dviju skupina (radiološki tehničari i medicinske sestre). Cilj studije bio je usporediti izvješća našega Zavoda i drugih PET/CT centara u svijetu u pogledu godišnjega broja postupaka, granica izloženosti osoblja te mogućnosti uvođenja dodatnih poboljšanja mjera zaštite od zračenja. Ustanovljeno je da se broj postupaka znatno povećao (s 208 u 2016. na 876 u 2019. godini), a tijekom praćenoga sedmomjesečnog razdoblja iznosio je 423. Srednja vrijednost pojedinačne doze za cijelo tijelo po jedinici aplicirane aktivnosti 18F-FDG [Hp(10)/A] iznosila je 18,55 μSv/GBq za četvero radioloških tehničara i 15,61 μSv/GBq za dvije medicinske sestre. Srednja vrijednost doze za dominantnu ruku po jedinici aplicirane aktivnosti 18F-FDG [Hp(0,07)/A] iznosila je 16,99 μSv/GBq i 25,44 μSv/GBq za te dvije skupine. Srednja vrijednost godišnje kumulativne doze za svih šestero zaposlenih iznosila je (1,06±0,29) mSv za Hp(10) i (1,15±0,32) mSv za Hp(0,07). Ovi su rezultati usporedivi s rezultatima sličnih studija. Doze za osoblje bile su znatno ispod propisanih godišnjih limita. Medicinske sestre imale su nešto više vrijednosti doza za ekstremitete (ruke) nego radiološki tehničari. Imajući u vidu tendenciju povećanja broja PET/CT postupaka, potrebno je nastaviti monitoring doza za osoblje kako bi se identificirale faze radnoga procesa koje dovode do najveće izloženosti osoblja, a zatim smanjile doze za osoblje

Determination of indoor radon concentration and radon concentration in soil: Regional Interlaboratory Comparison – RADON2021

In accordance with ISO/IC 17025:2017 testing laboratory shall have a procedure for monitoring the validity of results that includes regular participation in interlaboratory comparisons. Interlaboratory comparison RADON2021 was organized in the frame of the bilateral project between Serbia and Montenegro: “Measurement of the radon equilibrium factor in typical residential buildings in Serbia and Montenegro and harmonization of radon measurement techniques” in order to assess congruence of different measurement techniques, and then harmonize methods in case of inconsistencies. Harmonization is of particular importance to neighboring countries, in order to avoid inconsistencies in the classification of radon risk zones along border areas. Thus, six regional laboratories took part in the intercomparison – three from Belgrade and one from Novi Sad, Serbia; one from Podgorica, Montenegro; one from Banja Luka, Bosnia and Herzegovina. All laboratories participated in the indoor radon measurements, while 4 laboratories measured radon in the soil also. The measurement methods and detectors used by the laboratories were: • for air - EPA 402-R-92-004 – Indoor Radon and Radon Decay Product Measurement Devices Protocols, ch. 3.1. with RAD 7, RTM1688-2 and RadonEye; EPA 520/5-87-005 – 1987 EERF Standard Operating Procedures for Rn-222 Measurement Using Charcoal Canisters, ch. 3.4 using adsorption on charcoal canisters; ISO 11665- 4: Measurement of radioactivity in the environment – Air Radon 222: Part 4: Integrated measurement method for determining average activity concentration using passive sampling and delayed analysis with Electretes, and • for soil gas - ISO 11665-11:2016 Measurement of radioactivity in the environment — Air: radon-222 — Part 11: Test method for soil gas with sampling at depth by using active devices RTM1688-2 and RAD 7. The measurements were performed in real conditions where the radon concentration varied following a typical daily variation. Indoor radon concentrations were measured at four locations, while radon measurements in soil were performed at one location, all at the Vinča Institute site in the period from October 1 to October 8, 2021. The exposure period was consistent with a typical soil and indoor radon measurement protocols. The radon concentration in the soil was measured at depths of 20 cm and 80 cm. The robust mean and robust standard deviation were calculated as the mean of all measured radon concentrations (excluding outliers) and their standard deviation. Reference values of indoor radon covered the wide range of concentrations: (65 ± 9) Bq m-3 , (519 ± 80) Bq m-3 , (900 ± 160) Bq m-3 , (1980 ± 160) Bq m-3 , while in the soil reference values were (13350 ± 780) Bq m-3 and (26100 ± 2400) Bq m-3 at 20 cm and 80 cm depth, respectively. In order to assess whether there is a statistically significant difference between individual measurement results and the reference value, the Z - test was used as a criterion for success. If, for the calculated z value, |z| 3 result is not acceptable. All results of indoor radon measurements were satisfactory, except in the case of one measurement (for the lowest reference value) with electret, that was at the detection limit. Three laboratories had satisfactory results of radon concentration measurements in the soil, while the results of one laboratory were systematically lower, with z <-3, which indicated the need for additional analysis of the causes of systematic error and the possible need to change measurement protocols and/or re-calibration of used device.X JUBILEE International Conference on Radiation in Various Fields of Research : RAD 2022 (Spring Edition) : book of abstracts; June 13-17, 2022; Herceg Novi, Montenegr

Elastic electron scattering cross sections for triethyl phosphate molecule at intermediate electron energies from 50 eV to 250 eV

We present a combined experimental and theoretical study of the electron elastic differential cross sections of triethyl phosphate molecule (C2H5)3PO4 (TEP). The experimental setup based on a crossed beam technique comprising of an electron gun, a single capillary gas needle and a detection system with a channeltron was used to measure differential cross sections. The absolute scale for the cross sections is obtained by relative-flow method using argon gas as a reference. For the interpretation of the measured data we applied the partial expansion method to calculate the elastic cross sections of TEP. We found excellent agreement between the shapes of measured and calculated data

Absolute differential cross-sections for elastic electron scattering from sevoflurane molecule in the energy range from 50–300 ev

We report the results of the measurements and calculations of the absolute differential elastic electron scattering cross-sections (DCSs) from sevoflurane molecule (C4H3F7O). The experimental absolute DCSs for elastic electron scattering were obtained for the incident electron energies from 50 eV to 300 eV, and for scattering angles from 25◦ to 125◦ using a crossed electron/target beams setup and the relative flow technique for calibration to the absolute scale. For the calculations, we have used the IAM-SCAR+I method (independent atom model (IAM) applying the screened additivity rule (SCAR) with interference terms included (I)). The molecular cross-sections were obtained from the atomic data by using the SCAR procedure, incorporating interference term corrections, by summing all the relevant atomic amplitudes, including the phase coefficients. In this approach, we obtain the molecular differential scattering cross-section (DCS), which, integrated over the scattered electron angular range, gives the integral scattering cross-section (ICS). Calculated cross-sections agree very well with experimental results, in the whole energy and angular range