C. Feoli, M. Sannino
Università di Napoli Federico II, Dipartimento di Fisica “Ettore Pancini”, Napoli, Italia
Introduzione
Lo scopo dello studio è la valutazione della qualità di immagini di due fantocci mammografici acquisite con un Digital Breast Thomosynthesis (DBT) scanner. I parametri analizzati in questo studio sono la risoluzione spaziale, il contrasto e la presenza di artefatti. È stato effettuato un confronto con immagini mammografiche dello stesso fantoccio.
Materiali e metodi
I fantocci utilizzati sono il modello 020 BR3D e il modello 014AD prodotti dalla CIRS, con composizione ghiandolare equivalente BR50/50. Questi, differenti per omogeneità del materiale, sono costituiti da sei slab, in una delle quali sono presenti inserti di varia natura simulanti micro-calcificazioni, fibre e masse. Lo scanner DBT utilizzato è il Siemens Mammomat Inspiration. I parametri di acquisizione sono differenti per i due fantocci: 29 kVp, 318.3 mAs, W/Rh anodo/filtro, 3.43 mGy dose ghiandolare media (MGD) per il primo, e 32 kVp, 497.5 mAs, W/Rh anodo/filtro, 5.33 mGy MGD per il secondo. Sono stati valutati i seguenti parametri di qualità dell’immagine: risoluzione spaziale, contrast-to-noise ratio normalizzato alla dose (CNRD), linearità spaziale longitudinale e trasversa, e presenza di artefatti.
Risultati
Nei grafici mostrati in figura 1-4 sono riportati i risultati relativi ai parametri di qualità studiati. Modello 020 BR3D: 1) il valore del CNR per una massa di 6.3 mm è nel range di 0.27-5.29 (Fig 1. b); 2) in DBT è possibile visualizzare fibre fino a 0.38 mm e cluster di micro calcificazioni di 0.196 mm (Fig 2. b); 3) in DBT la risoluzione spaziale, valutata sulle micro-calcificazioni non varia in funzione della distanza dal rivelatore (Fig 3. b, Fig 4. b). Modello 014 AD: 1) il valore del CNR, valutato sul dispositivo per la valutazione del contrasto presente in una delle slab decresce all’aumentare della distanza dal rivelatore (Fig 1. a); 2) in DBT la risoluzione spaziale valutata sulle fibre varia in funzione della distanza dal rivelatore (Fig. 3 a, Fig 4 a); 3) sono presenti artefatti di “streak” e di “out of plane”.
0 10 20 30 40 50 60 70 80 0.2 0.4 0.6 0.8 1.0
CNRD
distanza dalla superficie d'ingresso(mm) DM DBT
014 AD
Fig.A 10 20 30 40 50 60 0.0 0.9 1.8 2.7 3.6 4.5 Fig.B CNRDdistanza dalla superficie d'ingresso (mm) DM
DBT Massa = 6.3 mm
020 BR3D
Figura 1: Misure di CNRD in funzione della distanza dalla superficie di ingresso. A destra: misure relative al fantoccio
CIRS 014 AD valutate sul dispositivo dedicato al contrasto. A sinistra: misure relative al fantoccio CIRS 020 BR3D valutate sulla massa di diametro 6.3 mm. Legenda: con DM e DBT si indicano rispettivamente le misure relative alle immagini mammografiche e di tomosintesi.
30 0 15 30 45 60 75 0.3 0.4 0.5 0.6 Fig.A FWHM (mm)
distanza dalla superficie d'ingresso(mm) DBT DM
014 AD, calcificazione (0.39 mm)
10 20 30 40 50 60 0.39 0.42 0.45 0.48 Fig.B020 BR3D, calcificazione (0,40 mm)
FWH M (mm)distanza dalla superficie di ingresso (mm) DBT DM
actual -c size
Figura 2: Misure di risoluzione spaziale in termini di FWHM (mm) in funzione della distanza dalla superficie di
ingresso. La risoluzione è stata valutata considerando il cluster di micro-calcificazioni di 0.39 mm; a destra sono indicate le misure relative al CIRS 014 AD, a sinistra quelle relative al CIRS 020 BR3D. Legenda: con DM e DBT si indicano rispettivamente le misure relative alle immagini mammografiche e di tomosintesi.
10 20 30 40 50 60 70 80 90 2.8 3.0 3.2 3.4 3.6 3.8
014 AD
Fig.Apendenza del fit lineare = (5+3)E-4
distanz
a fra c
alcific
azioni (mm)
distanza dal rivelatore (mm)
DM DBT pendenza del fit lineare =
(5.9+0.6)E-3 10 20 30 40 50 60 10 12 14 16 18 Fig.B DM DBT Distanz a tra calcificaz ioni (mm)
distanza dal rivelatore (mm)
pendenza del fit lineare = 1,4337
pendenza del fit lineare = 0,00869
020 BR3D
Figura 3: Valutazione di linearità spaziale trasversa al variare della distanza del dettaglio dal rivelatore. Le misure sono
relative al fantoccio CIRS 014 AD a destra, e al CIRS 020 BR3D a sinistra, valutate sulla distanza tra due micro-calcificazioni di 0.39 mm appartenenti allo stesso cluster. Legenda: con DM e DBT si indicano rispettivamente le misure relative alle immagini mammografiche e di tomosintesi.
0 15 30 45 60 75 0 15 30 45 60 75 Fig.A Y=1.19182+0.96828*X R2>0.9996 DBT 014 AD posizione della f etta D BT (mm)
distanza dalla superficie d'ingresso (mm)
Figura 4: Valutazione di linearità spaziale longitudinale al variare della distanza della slice ricostruita in DBT dalla
superficie di ingresso. Le misure sono relative al fantoccio CIRS 014 AD (a destra) e al CIRS 020 BR3D (a sinistra). Legenda: con DM e DBT si indicano rispettivamente le misure relative alle immagini mammografiche e di tomosintesi.
0 10 20 30 40 50 60 0 10 20 30 40 50 60 020 BR3D Fig.B Y=1.738+1.014*X R2>0.9996 DBT pos izione della fett a DBT (mm)
31 Conclusioni
La qualità delle immagini analizzate è migliore in DBT in presenza di rumore anatomico (020 BR3D), minore in mammografia in assenza di esso (014 AD).
Referenze
[1]C. Feoli, A. Sarno, F. Di Lillo, G. Mettivier, P. Russo, Image quality in Digital Breast Tomosynthesis: a phantom assessment, Physica Medica; 2016, February, Volume 32
[2]Siemens Mammomat Inspiration, Data Sheet, www.siemens.com;
[3]www.cirs.com; Data Sheet CIRS 020 BR3D
[4]Thomas Mertelmeier, Jutta Speitel and Claudia Frumento, 3D breast tomosynthesis – intelligent technology for clear clinical benefits. www.siemens.com/healthcare.
[5] Rafael Gonzalez, C.; Woods, Richard. Digital image processing. Pearson Education, 2002. [6] Edition by Jerrold T. Bushberg, J. Anthony Seibert, Edwin M. Leidholdt Jr., John M. Boone. The Essential Physics of Medical Imaging, Third Edition, North American Edition.
RADIORESISTANCE OF DWARF BEAN PLANTS IRRADIATED WITH C AND Ti HEAVY IONS
Ermenegilda Vitale1, Veronica De Micco 2, Bruno Hay Mele2, Chiara Amitrano1, Anna De
Maio1, Simona Carfagna1, Carmen Arena1*
1Department of Biology, University of Naples Federico II, Naples, Italy
2Department of Agricultural Sciences, University of Naples Federico II, Portici (NA), Italy
*email: erm.vitale@studenti.unina.it Introduction
Long-duration space missions and habitation of platforms and planetary stations on Moon and Mars depend on the realization of Bioregenerative Life Support Systems (BLSSs), miniature ecosystems where each component, human, plants and microbes, supports and is support by each of the others. However the Space environment differs from Earth for several conditions, like temperature, pressure, microgravity and presence of cosmic radiation. Then preliminary studies with high energetic particles were carried out to provide information about the capability of plants to withstand ionizing radiation in Space. On Earth plants developed efficient mechanisms of radioresistance, for example polyploidy, antioxidants production and cellular structure which allow plants to be more radioresistant than animals [1]. Moreover the response of plants to ionizing radiation depends on radiation features and vegetal intrinsic characteristics like species, cultivar, phenological stage, eco-phisiological, biochemical responses and so on [2]. Then, if high or intermediate doses of high-LET ionizing radiation could induce deleterious or harmful consequences, non-lethal levels may stimulate physiological and morphological traits in plants [3] increasing their ability to be cultivated in extraterrestrial environments. Today mutation-based breeding carried out with ionizing radiation develops and improves plant productivity and quality [4] representing a bi-sided goal for the introduction of plants in the BLSSs and the improvement of specific crops. In this study, we test the radioresistance of Dolichos melanophtalmus DC. (dwarf bean), a species with suitable traits for cultivation in space, meaning dwarf size, short life cycle, high nutritional content. Seeds were irradiated with low doses (1 and 10 Gy) of heavy ions, namely C and Ti to evaluate the possible occurrence of stimulatory effects in terms of growth, photosynthetic efficiency and antioxidant response.
32 Materials and methods
Dry seeds of Dolichos melanophtalmus DC. were irradiated with Carbon and Titanium heavy ions (LET: 80 keV/m; LET: 108 keV/m) at the doses of 1 and 10 Gy. The irradiation was performed at the heavy-ion synchrotron (SIS) at GSI Helmholtzzentrum für Schwerionenforschung GmbH, (Darmstadt, Germany). After irradiation, irradiated and control seeds were transferred at the Department of Biology of the University of Naples Federico II (Naples, Italy) where plants were cultivated from seed-to-seed in a growth chamber under controlled conditions (T 25°C; RH 60%; 190 PPFD (μmol photons m-2s-1). After germination, alterations in growth were recorded by morphometric analysis; the photosynthetic efficiency was evaluated by chlorophyll a fluorescence emission measurements and determination of photosynthetic pigments’content. The occurrence of oxidative stress and plant capability to withstand it were tested by measuring the intracellular H2O2
level, the ascorbic acid content and the poly (ADPribose) polymerase (PARP) activity following Arena et al. (2014)[5].
Results and discussion
The irradiation of the seeds with different types of heavy ions and doses did not prevent either seed germination or the completion of plant life cycle; indeed irradiated plants were able to produce pods and a new generation of seeds with significant lower values for C 10 Gy plants (Table 1). Stimulatory effects on plant height were observed at 1 Gy dose and Ti 10 Gy, whereas C 10 Gy treatment determined a decrease in plant growth in terms of height (Table 1). The dose of C 10 Gy also reduced plants photochemical performance, in facts these plants showed significant lower electron transport rate (ETR) and maximal photochemical efficiency (Fv/Fm) (Fig.1) and recorded a significant decrease of total chlorophylls and carotenoids compared to other treatments (Table 2), indicating the occurrence of damages at the photosystem level. However, in C and Ti 10 Gy treated plants, the increase in intracellular H2O2 concentration, together with the rise in ascorbic acid content and PARP activity (Fig.2), suggests the occurrence of a radio-induced oxidative stress mitigated by plant capability to activate the defense mechanisms successfully.
Table 1: Germination percentage, number of pods and seeds, plant height of Dolichos melanophtalmus DC. plants germinated from control and irradiated seeds with C and Ti heavy ions at doses of 1 and 10 Gy. Each value represents the mean ± SE (n = 5). Different letters indicate statistically significant differences among treatments (P<0,05). Control C 1 Gy C 10 Gy Ti 1 Gy Ti 10 Gy % Germination 100 ±3,00 a 85 ±2,0 b 80 ±4,0 b 100 ±1,00 a 100 ±1,5 a Pod number 10 ±0,5 a 9 ±0,7 a 7 ±0,4 b 10 ±1,0 a 9 ±0,6 a Seed number 17 ±2,0 a 13 ±3,0 a 8 ±1,0 b 15 ±2,0 a 13 ±2,0 a Plant Height (cm) 25 ±1,5 a 36 ±0,4 a 15 ±0,8 b 42 ±0,2 a 43 ±0,9 a
33
Table 2: Content of total chlorophylls (a+b) and carotenoids (x+c) in leaves of Dolichos melanophtalmus DC. plants germinated from control and irradiated seeds with C and Ti heavy ions at doses of 1 and 10 Gy. Each value represents the mean ± SE (n = 5). Different letters indicate statistically significant differences among treatments (P<0,05). Control C 1 Gy C 10 Gy Ti 1 Gy Ti 10 Gy Chl (a+b) mg g-1 2,29 ±0,11 a 2,40 ±0,15 a 1,57 ±0,10 b 2,17 ±0,13 a 2,09 ±0,10 a Car (x+c) mg g-1 0,29 ±0,01 a 0,37 ±0,02 a 0,24 ±0,01 b 0,30 ±0,02 a 0,26 ±0,03 a
Figure 1: Electron transport rate ETR (A) and maximal photochemical efficiency Fv/Fm (B) of Dolichos melanophtalmus DC. plants germinated from control and irradiated seeds with C and Ti heavy ions at doses of 1 and 10 Gy. Each value represents the mean ± SE (n = 5). Different letters indicate statistically significant differences among treatments (P<0,05).
Figure 2: Intracellular H2O2 concentration (A), ascorbic acid content (B) and PARP activity (C) of Dolichos melanophtalmus DC. plants germinated from control and irradiated seeds with C and Ti heavy ions at doses of 1 and 10 Gy. Each value represents the mean ± SE (n = 5). Different letters indicate statistically significant differences among treatments (P<0,05).
Conclusions
The irradiation with C and Ti heavy ions do not compromise plant phenological phases, as all plants complete the life cycle from seed-to-seed. However the different ions, depending on dose, induce diverse effects on plant growth, photosynthesis and antioxidant production. In particular, C and Ti at the dose of 1 Gy stimulate plants height compared to control; conversely, C ions at 10 Gy dose cause a reduction of growth, photosynthetic
activity and plant reproductive capacity, and determine an increase of intracellular H2O2 concentration,
ascorbic acid content and PARP activity. It is supposable that, in these plants, the irradiation with 10 Gy C ions have induced an oxidative stress that have stimulated the occurrence of cell defence mechanisms.
34 References
[1] Arena C., De Micco V., Macaeva E. and Quintes R. (2014), Space radiation effects on plant and mammalian cells. ActaAstronautica 104:419-431.
[2][3] De Micco V., Arena,C. Pignalosa D. and Durante M. (2011), Effects of sparsely and densely ionizing radiation on plants. Rad. Env. Biophys. 50:1–19.
[4] Oladosu Y., Rafii M.Y., Abdullah N., Hussin G., Ramli A., Rahim H.A., Miah G. and Usman M. (2016), Principle and application of plant mutagenesis in crop improvement: a review. Biotechnology & Biotechnological Equipment 30:1-16.
[5] Arena C., De Maio A., De Nicola F., Santorufo L., Vitale L. and Maisto G. (2014), Assessment of eco-physiological performance of Quercus ilex L. leaves in urban area by an integrated approach. Water Air and Soil Pollution 225:1812-1824
A PREDICTIVE VERSION OF THE BIANCA BIOPHYSICAL MODEL TO CALCULATE