Publications by authors named "Domiziano Mostacci"

12 Publications

  • Page 1 of 1

Radiation protection and dosimetry issues for patients with prostate cancer after I-125 low-dose-rate brachytherapy permanent implant.

Brachytherapy 2021 Jan-Feb;20(1):272-278. Epub 2020 Oct 9.

Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola FC, Italy.

Purpose: The aim of this work was to analyze the exposure rates measured in the proximity of patients who underwent prostate low-dose-rate brachytherapy with I-125 implant. Effective doses to relatives and to population were computed to estimate the time to reach radioprotection dose constraints.

Methods And Materials: Measurements were obtained from 180 patients, whereas the body mass index was calculated and reported for 77 patients. The day after the implant, K˙ measurements were conducted at various skin distances and positions and converted to effective doses. A theoretical model was developed to estimate effective doses from total implanted activity. The latter was approximated with a 10-mL vial inside the patient.

Results: The K˙ measurements showed a low correlation with the total implanted activity, albeit an increasing trend of K˙ was observed on increasing the activity. A stronger correlation was found between body mass index and K˙ measurements. The effective dose to population is in general lower than dose constraints as well as the effective doses to relatives, with the exception of children and pregnant women, who command special precautions. We report differences between the experimental model- and theoretical model-based dose evaluation together with their comparison with previous studies found in literature.

Conclusions: Based on the K˙ measurements and the results of the present analysis, it is possible to provide the patient with radiation safety instructions specifically tailored to his relatives' habits and working environment.
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http://dx.doi.org/10.1016/j.brachy.2020.09.003DOI Listing
October 2020

Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device.

PLoS One 2018 29;13(6):e0199312. Epub 2018 Jun 29.

University of Bologna, Department of Physics and Astronomy, Bologna, Italy.

Radiation therapy is a useful and standard tumor treatment strategy. Despite recent advances in delivery of ionizing radiation, survival rates for some cancer patients are still low because of recurrence and radioresistance. This is why many novel approaches have been explored to improve radiotherapy outcome. Some strategies are focused on enhancement of accuracy in ionizing radiation delivery and on the generation of greater radiation beams, for example with a higher dose rate. In the present study we proposed an in vitro research of the biological effects of very high dose rate beam on SK-Mel28 and A375, two radioresistant human melanoma cell lines. The beam was delivered by a pulsed plasma device, a "Mather type" Plasma Focus for medical applications. We hypothesized that this pulsed X-rays generator is significantly more effective to impair melanoma cells survival compared to conventional X-ray tube. Very high dose rate treatments were able to reduce clonogenic efficiency of SK-Mel28 and A375 more than the X-ray tube and to induce a greater, less easy-to-repair DNA double-strand breaks. Very little is known about biological consequences of such dose rate. Our characterization is preliminary but is the first step toward future clinical considerations.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0199312PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025851PMC
April 2019

A Mathematical Realization of Entropy through Neutron Slowing Down.

Entropy (Basel) 2018 Mar 28;20(4). Epub 2018 Mar 28.

Department of Industrial Engineering, University of Bologna, 40136 Bologna, Italy.

The slowing down equation for elastic scattering of neutrons in an infinite homogeneous medium is solved analytically by decomposing the neutron energy spectrum into collision intervals. Since scattering physically smooths energy distributions by redistributing neutron energy uniformly, it is informative to observe how mathematics accommodates the scattering process, which increases entropy through disorder.
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http://dx.doi.org/10.3390/e20040233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7512748PMC
March 2018

Assessment of the neutron dose field around a biomedical cyclotron: FLUKA simulation and experimental measurements.

Phys Med 2016 Dec 3;32(12):1602-1608. Epub 2016 Dec 3.

Medical Physics Department, University Hospital "S. Orsola-Malpighi", Via Massarenti 9, 40138 Bologna, Italy.

In the planning of a new cyclotron facility, an accurate knowledge of the radiation field around the accelerator is fundamental for the design of shielding, the protection of workers, the general public and the environment. Monte Carlo simulations can be very useful in this process, and their use is constantly increasing. However, few data have been published so far as regards the proper validation of Monte Carlo simulation against experimental measurements, particularly in the energy range of biomedical cyclotrons. In this work a detailed model of an existing installation of a GE PETtrace 16.5MeV cyclotron was developed using FLUKA. An extensive measurement campaign of the neutron ambient dose equivalent H(10) in marked positions around the cyclotron was conducted using a neutron rem-counter probe and CR39 neutron detectors. Data from a previous measurement campaign performed by our group using TLDs were also re-evaluated. The FLUKA model was then validated by comparing the results of high-statistics simulations with experimental data. In 10 out of 12 measurement locations, FLUKA simulations were in agreement within uncertainties with all the three different sets of experimental data; in the remaining 2 positions, the agreement was with 2/3 of the measurements. Our work allows to quantitatively validate our FLUKA simulation setup and confirms that Monte Carlo technique can produce accurate results in the energy range of biomedical cyclotrons.
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http://dx.doi.org/10.1016/j.ejmp.2016.11.115DOI Listing
December 2016

Radiation Protection Studies for Medical Particle Accelerators using Fluka Monte Carlo Code.

Radiat Prot Dosimetry 2017 Apr;173(1-3):185-191

Medical Physics Department, S. Orsola-Malpighi University Hospital, Via Massarenti 9, 40138 Bologna, Italy.

Radiation protection (RP) in the use of medical cyclotrons involves many aspects both in the routine use and for the decommissioning of a site. Guidelines for site planning and installation, as well as for RP assessment, are given in international documents; however, the latter typically offer analytic methods of calculation of shielding and materials activation, in approximate or idealised geometry set-ups. The availability of Monte Carlo (MC) codes with accurate up-to-date libraries for transport and interaction of neutrons and charged particles at energies below 250 MeV, together with the continuously increasing power of modern computers, makes the systematic use of simulations with realistic geometries possible, yielding equipment and site-specific evaluation of the source terms, shielding requirements and all quantities relevant to RP at the same time. In this work, the well-known FLUKA MC code was used to simulate different aspects of RP in the use of biomedical accelerators, particularly for the production of medical radioisotopes. In the context of the Young Professionals Award, held at the IRPA 14 conference, only a part of the complete work is presented. In particular, the simulation of the GE PETtrace cyclotron (16.5 MeV) installed at S. Orsola-Malpighi University Hospital evaluated the effective dose distribution around the equipment; the effective number of neutrons produced per incident proton and their spectral distribution; the activation of the structure of the cyclotron and the vault walls; the activation of the ambient air, in particular the production of 41Ar. The simulations were validated, in terms of physical and transport parameters to be used at the energy range of interest, through an extensive measurement campaign of the neutron environmental dose equivalent using a rem-counter and TLD dosemeters. The validated model was then used in the design and the licensing request of a new Positron Emission Tomography facility.
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http://dx.doi.org/10.1093/rpd/ncw302DOI Listing
April 2017

Assessment of lithogenic radioactivity in the Euganean Hills magmatic district (NE Italy).

J Environ Radioact 2017 Jan 21;166(Pt 2):259-269. Epub 2016 Jul 21.

Dept. of Geosciences, Univ. of Padova, Via Gradenigo 6, I-25131 Padova, Italy.

The Euganean Hills of North East Italy have long been recognised as an area characterized by a higher than average natural radiation background. This is due to two main reasons: a) primary lithogenic radiation due to rhyolitic and trachytic outcrops, which are "acidic alkaline" magmatic rocks potentially enriched in uranium and thorium; b) secondary sources related to a geothermal field - widely exploited for spa tourism in the area since the Roman age - producing surface release of radon-enriched fluids. Though radioactivity levels in the Euganean district have been often investigated in the past - including recent works aimed at assessing the radiation doses from radon and/or total gamma radiation - no effort has been put so far into producing a thorough assessment linking radiation protection data to geological-structural features (lithology, faults, water, organic matter content, etc.). This work represents the first part of the interdisciplinary project "Geological and geochemical control on Radon occurrence and natural radioactivity in the Euganean Hills district (North-Eastern Italy)", aimed at producing detailed results of the actual radiation levels in connection mainly with lithological parameters. A detailed sampling strategy, based on lithostratigraphy, petrology and mineralogy, has been adopted. The 151 rock samples collected were analyzed by high resolution γ-ray spectrometry with ex situ HPGe detectors. Statistical and geostatistical analyses were performed, and outlier values of U and Th - possibly associated with anomalies in the geological formation - were identified. U, Th and K concentration maps were developed using both the entire database and then again after expunging the outliers; the two were then compared. In all maps the highest values can be associated to trachyte and rhyolite lithologies, and the lowest ones to sedimentary formations. The external dose due to natural radionuclides in the soil - the so called terrestrial gamma dose rate - has been calculated using the U, Th and K distribution measured in the bedrock samples.
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http://dx.doi.org/10.1016/j.jenvrad.2016.07.011DOI Listing
January 2017

Skin dose saving of the staff in 90Y/177Lu peptide receptor radionuclide therapy with the automatic dose dispenser.

Nucl Med Commun 2016 Oct;37(10):1046-52

aMedical Physics Unit bNuclear Medicine Unit, Arcispedale Santa Maria Nuova - IRCCS, Reggio Emilia cDepartment of Industrial Engineering, University of Bologna, Bologna, Italy.

Objective: When handling Y-labelled and Lu-labelled radiopharmaceuticals, skin exposure is mainly due to β-particles. This study aimed to investigate the equivalent dose saving of the staff when changing from an essentially manual radiolabelling procedure to an automatic dose dispenser (ADD).

Materials And Methods: The chemist and physician were asked to wear thermoluminescence dosimeters on their fingertips to evaluate the quantity of Hp(0.07) on the skin. Data collected were divided into two groups: before introducing ADD (no ADD) and after introducing ADD.

Results: For the chemist, the mean values (95th percentile) of Hp(0.07) for no ADD and ADD are 0.030 (0.099) and 0.019 (0.076) mSv/GBq, respectively, for Y, and 0.022 (0.037) and 0.007 (0.023) mSv/GBq, respectively, for Lu. The reduction for ADD was significant (t-test with P<0.05) for both isotopes. The relative differences before and after ADD collected for every finger were treated using the Wilcoxon test, proving a significantly higher reduction in extremity dose to each fingertip for Lu than for Y (P<0.05). For the medical staff, the mean values of Hp(0.07) (95th percentile) for no ADD and ADD are 0.021 (0.0762) and 0.0143 (0.0565) mSv/GBq, respectively, for Y, and 0.0011 (0.00196) and 0.0009 (0.00263) mSv/GBq, respectively, for Lu. The t-test provided a P-value less than 0.05 for both isotopes, making the difference between ADD and no ADD significant.

Conclusion: ADD positively affects the dose saving of the chemist in handling both isotopes. For the medical staff not directly involved with the introduction of the ADD system, the analysis shows a learning curve of the workers over a 5-year period. Specific devices and procedures allow staff skin dose to be limited.
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http://dx.doi.org/10.1097/MNM.0000000000000548DOI Listing
October 2016

Calibration with MCNP of NaI detector for the determination of natural radioactivity levels in the field.

J Environ Radioact 2016 May 22;155-156:31-37. Epub 2016 Feb 22.

Laboratoire de Physique des Radiations, Institut Supérieur Industriel de Bruxelles, H.-E. Paul-Henri Spaak, Rue Royale, 150, 1000 Bruxelles, Belgium.

In view of assessing natural radioactivity with on-site quantitative gamma spectrometry, efficiency calibration of NaI(Tl) detectors is investigated. A calibration based on Monte Carlo simulation of detector response is proposed, to render reliable quantitative analysis practicable in field campaigns. The method is developed with reference to contact geometry, in which measurements are taken placing the NaI(Tl) probe directly against the solid source to be analyzed. The Monte Carlo code used for the simulations was MCNP. Experimental verification of the calibration goodness is obtained by comparison with appropriate standards, as reported. On-site measurements yield a quick quantitative assessment of natural radioactivity levels present ((40)K, (238)U and (232)Th). On-site gamma spectrometry can prove particularly useful insofar as it provides information on materials from which samples cannot be taken.
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http://dx.doi.org/10.1016/j.jenvrad.2016.02.009DOI Listing
May 2016

Experimental measurement and Monte Carlo assessment of Argon-41 production in a PET cyclotron facility.

Phys Med 2015 Dec 26;31(8):991-996. Epub 2015 Sep 26.

Medical Physics Department, University Hospital "S. Orsola-Malpighi", Via Massarenti 9, 40138, Bologna, Italy.

In a medical cyclotron facility, (41)Ar (t1/2 = 109.34 m) is produced by the activation of air due to the neutron flux during irradiation, according to the (40)Ar(n,γ)(41)Ar reaction; this is particularly relevant in widely diffused high beam current cyclotrons for the production of PET radionuclides. While theoretical estimations of the (41)Ar production have been published, no data are available on direct experimental measurements for a biomedical cyclotron. In this work, we describe a sampling methodology and report the results of an extensive measurement campaign. Furthermore, the experimental results are compared with Monte Carlo simulations performed with the FLUKA code. To measure (41)Ar activity, air samples were taken inside the cyclotron bunker in sealed Marinelli beakers, during the routine production of (18)F with a 16.5 MeV GE-PETtrace cyclotron; this sampling thus reproduces a situation of absence of air changes. Samples analysis was performed in a gamma-ray spectrometry system equipped with HPGe detector. Monte Carlo assessment of the (41)Ar saturation yield was performed directly using the standard FLUKA score RESNUCLE, and off-line by the convolution of neutron fluence with cross section data. The average (41)Ar saturation yield per one liter of air of (41)Ar, measured in gamma-ray spectrometry, resulted to be 3.0 ± 0.6 Bq/µA*dm(3) while simulations gave a result of 6.9 ± 0.3 Bq/µA*dm(3) in the direct assessment and 6.92 ± 0.22 Bq/µA*dm(3) by the convolution neutron fluence-to-cross section.
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http://dx.doi.org/10.1016/j.ejmp.2015.07.146DOI Listing
December 2015

Comparison of radioactivity data measured in PM10 aerosol samples at two elevated stations in northern Italy during the Fukushima event.

J Environ Radioact 2012 Dec 16;114:105-12. Epub 2012 Feb 16.

Dipartimento di Chimica Giacomo Ciamician, Alma Mater Studiorum Università di Bologna, Via Selmi 2, 40126 Bologna (BO), Italy.

The follow-up of Fukushima radioactive plume resulting from the 11th March 2011 devastating tsunami is discussed for two Italian stations in the northern Apennines: Mt. Cimone (Modena) and Montecuccolino (Bologna). Radioactivity data collected at both stations are described, including comparison between local natural background of airborne particulate and artificial radioactivity referable to the arrival of the radioactive plume and its persistence and evolution. Analysis of back-trajectories was used to confirm the arrival of artificial radionuclides following atmospheric transport and processing. The Fukushima plume was first detected on 3rd April 2011 when high volume sampling revealed the presence of the artificial radionuclides (131)I, (137)Cs and (134)Cs. The highest activity concentrations of these nuclides were detected on 5th April 2011 at the Montecuccolino site. Fukushima radioactivity data at the two stations were usually comparable, suggesting a good vertical mixing of the plume; discrepancies were occasional and attributed to different occurrence of wet removal, typically characterized by a scattered spatial pattern. To understand the relevance to the local population of the extra dose due to the Fukushima plume, atmospheric activities of the related artificial nuclides were compared to those of the main natural radionuclides in ambient particulate, and found to be lower by over one order of magnitude. Radiation doses referable to Fukushima, maximized for a whole year occurrence at the highest activity level observed at our stations in the weeks affected by the Japanese plume, were estimated at 1.1 μSv/year.
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http://dx.doi.org/10.1016/j.jenvrad.2012.01.016DOI Listing
December 2012

Solving radiative transfer problems in highly heterogeneous media via domain decomposition and convergence acceleration techniques.

Appl Radiat Isot 2011 Aug 25;69(8):1146-50. Epub 2010 Nov 25.

Aerospace and Mechanical Engineering Department, The University of Arizona, 1130 N Mountain Ave, Tucson, AZ 85721, USA.

This paper deals with finding accurate solutions for photon transport problems in highly heterogeneous media fastly, efficiently and with modest memory resources. We propose an extended version of the analytical discrete ordinates method, coupled with domain decomposition-derived algorithms and non-linear convergence acceleration techniques. Numerical performances are evaluated using a challenging case study available in the literature. A study of accuracy versus computational time and memory requirements is reported for transport calculations that are relevant for remote sensing applications.
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http://dx.doi.org/10.1016/j.apradiso.2010.11.016DOI Listing
August 2011

Assessment of internal contamination hazard and fast monitoring for workers involved in maintenance operations on PET cyclotrons.

Radiat Prot Dosimetry 2011 Mar 3;144(1-4):468-72. Epub 2010 Nov 3.

Department of Energy, Nuclear and Environmental Control Engineering, University of Bologna, Bologna, Italy.

With the ever-increasing number of cyclotron installations, and therefore of the maintenance personnel involved, the possibility of swift, 'yes or no' screening for internal contamination becomes a prized asset. The present work presents one such procedure, evolved from an approximate whole body counting technique in widespread use in emergency situations. A detailed analysis of possible pathways for contamination leads to pinpointing the nuclides of interest. Different calibration methods are applied, showing moderate variation among them. The minimum detectable activity of order 1000 Bq is determined. The method proves sensitive enough to exclude significant contamination, or to identify its presence instantly  'on site' to prompt further in-depth investigation.
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http://dx.doi.org/10.1093/rpd/ncq327DOI Listing
March 2011