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240. Evaluation of 3D printing materials for breast phantoms for phase contrast imaging
210
Abstracts / Physica Medica 56 (2018) 133–278
Conclusion. The FNLS algorithm is suitable to achieve accurate T1 and ECV mapping. The values of ECV referred to healthy controls were in very good agreement with previously published results. ECV uncertainty, in terms of propagation of T1 errors, were limited and comparable with the healthy control inter-patient variability, confirming the accurate ECV quantification.
Reference
between on-centre and periphery ADC values varies from 5% and +3% and phase encoding effect is less than 0.5%. Gdd variations are around +1%. Acquisition plane differences are less than 1% at isocentre and of the order of 5% in periphery. SNR at isocenter is 550 and short term variation is 0.2%. Conclusions. The proposed protocol provides a simple QA procedure for DWI application. Selected indexes provide quantitative information on many relevant acquisition parameters. https://doi.org/10.1016/j.ejmp.2018.04.250
1. Altabella L et al.. A feasible and automatic free tool for T1 and ECV mapping. Physica Medica: Eur J Med Phys 2017;33:47–55. 240. Evaluation of 3D printing materials for breast phantoms for phase contrast imaging G. Esposito a, G. Mettivier a, K. Bliznakova b, P. Russo a, F. Di Lillo a, A. Sarno a, A. Bravin c, I. Buliev b, P. Popov b, D. Ivanov b
https://doi.org/10.1016/j.ejmp.2018.04.249
239. A protocol for advanced QA in DW L. Fedeli a, G. Belli b, A. Ciccarone c, A. Coniglio d, M. Esposito e, L.N. Mazzoni f, M. Giannelli g, C. Gori a, L. Nocetti h, R. Sghedoni i, R. Tarducci j, S, Busoni b a
University of Firenze, Dept. ‘‘Fisica e Astronomia”, Firenze, Italy A.O.U. Careggi, U.O.C. Fisica Sanitaria, Firenze, Italy c A.O.U. Mayer, Firenze, Italy d A.O. Fatebenefratelli, Roma, Italy e A.U.S.L. Toscana Centro, Firenze, Italy f A.U.S.L. Toscana Centro, Pistoia, Italy g A.O.U. Pisana, Pisa, Italy h A.O.U. Policlinico di Modena, Italy i A.U.S.L. di Reggio Emilia, Italy j A.O.U Perugia, Italy b
Purpose. The aim of this study is to propose a protocol for DWI QA being easy to implement while still providing quantitative information on relevant parameters for the scanner QC as well as for clinical applications. The measured quantity is the apparent diffusion coefficient (ADC) and its dependence from gradient diffusion direction (Gdd) and phase encoding direction (PED). Methods. A spherical water phantom (14 cm diameter), designed to allow fast and easy measurement of solution temperature, is proposed. The phantom is filled with doped aqueous solution (ADC value certified) and placed at isocentre of scanner. The protocol consists of five set of acquisition of 19 slices, repeated for three orthogonal Gdd. First and second acquisitions are identical, the others differ for the PED and acquisition plane. Each slice (for each Gdd) is acquired with six different b-values varying from 0 s/mm2 to 1000 s/mm2. From each acquisition and Gdd, ADC map of the phantom is generated with monoexponential fit, corrected for temperature and ADC profile along three orthogonal direction is extracted. From first two acquisitions short term reproducibility and SNR are evaluated; second and third acquisitions are used to detect phase encoding direction effects, lasts three maps are used to detect acquisition plane effects on ADC (details in Table 1). Results. A preliminary test of the protocol on 1.5T MRI scanner demonstrated its applicability to routine QA. Relative difference
a
Università di Napoli Federico II, Dipartimento di Fisica ‘‘Ettore Pancini” & INFN Napoli, Italy b Laboratory of Computer Simulations in Medicine, Technical University of Varna, Bulgaria c European Synchrotron Radiation Facility (ESRF), Grenoble, France Purpose. The aim of this work was to explore the available 3D printing technology and available range of printing materials such as resins, polylactic acid, nylon, ABS, etc. in order to determine their complex refractive index properties with respect to those of PMMA and of the breast tissues: adipose, glandular tissue and skin. Methods. Three step wedge phantoms were printed, each consisting of 3 steps with a rectangular area of 20 mm 35 mm for a total of 9 thicknesses ranging from 2 mm to 40 mm. Twenty stereolithographic plastic materials were investigated, including ABS, PLA, PVA, Nylon, Black, Hybrid and PET-G. We performed propagation based phase contrast projection imaging at ESRF (Grenoble, France), beamline ID17 at 30, 45 and 60 keV. Attenuation coefficients (derived from Lambert-Beer law) and refractive index decrements (derived using the Paganin phase retrieval algorithm) were derived in relative terms, with respect to propagation in an equivalent thickness of breast tissues. Results. The absolute difference in percent in terms of the attenuation coefficients and phase shift for different materials with respect to adipose tissue, glandular tissue, skin and PMMA, was measured respectively. Most materials show a difference of less than 5%. Conclusions. Twenty tissue substitute materials were considered as possible candidates to represent PMMA, adipose tissue, glandular tissue and skin. At 30 to 60 keV, the absolute percent difference between the glandular, adipose or skin and the substitute material was less than 5%. PVA material is the best representative for breast tissue and PMMA. https://doi.org/10.1016/j.ejmp.2018.04.251
241. Radiation risk due to medical imaging in long living patients: the case of Hodgkin lymphoma S. Chauvie a, N. Acchiardi b, A. De Maggi a,c, E. Roberto a, F. Bergesio a a
Table 1. Protocol structure and QA evaluated parameters (ST short term variation, CP central/periphery variation, GE gradient diffusion direction variation, PE phase encoding effect, AcP acquisition plane variation). Acquisition 1 2 3 4 5
Acq. Plane Axial Axial Axial Coronal Sagittal
Phase Encoding AP AP LR LR AP
QA parameters ST, CP, SNR, GE ST, PE, SNR CP, PE, AcP, GE CP, AcP, GE CP, AcP, GE
S. Croce e Carle Hospital, Medical Physics, Cuneo, Italy University of Torino, Italy c School of Medical Physics, University of Torino, Italy b
Purpose. Serious concern were risen in the scientific community on the risk of second cancer due to medical imaging in long-living cohort of patients with advanced stage Hodgkin Lymphoma (HL). The purpose of this work was to analyze a cohort of patient enrolled in a clinical trial to understand the type and number of medical
Abstracts / Physica Medica 56 (2018) 133–278
Conclusion. The FNLS algorithm is suitable to achieve accurate T1 and ECV mapping. The values of ECV referred to healthy controls were in very good agreement with previously published results. ECV uncertainty, in terms of propagation of T1 errors, were limited and comparable with the healthy control inter-patient variability, confirming the accurate ECV quantification.
Reference
between on-centre and periphery ADC values varies from 5% and +3% and phase encoding effect is less than 0.5%. Gdd variations are around +1%. Acquisition plane differences are less than 1% at isocentre and of the order of 5% in periphery. SNR at isocenter is 550 and short term variation is 0.2%. Conclusions. The proposed protocol provides a simple QA procedure for DWI application. Selected indexes provide quantitative information on many relevant acquisition parameters. https://doi.org/10.1016/j.ejmp.2018.04.250
1. Altabella L et al.. A feasible and automatic free tool for T1 and ECV mapping. Physica Medica: Eur J Med Phys 2017;33:47–55. 240. Evaluation of 3D printing materials for breast phantoms for phase contrast imaging G. Esposito a, G. Mettivier a, K. Bliznakova b, P. Russo a, F. Di Lillo a, A. Sarno a, A. Bravin c, I. Buliev b, P. Popov b, D. Ivanov b
https://doi.org/10.1016/j.ejmp.2018.04.249
239. A protocol for advanced QA in DW L. Fedeli a, G. Belli b, A. Ciccarone c, A. Coniglio d, M. Esposito e, L.N. Mazzoni f, M. Giannelli g, C. Gori a, L. Nocetti h, R. Sghedoni i, R. Tarducci j, S, Busoni b a
University of Firenze, Dept. ‘‘Fisica e Astronomia”, Firenze, Italy A.O.U. Careggi, U.O.C. Fisica Sanitaria, Firenze, Italy c A.O.U. Mayer, Firenze, Italy d A.O. Fatebenefratelli, Roma, Italy e A.U.S.L. Toscana Centro, Firenze, Italy f A.U.S.L. Toscana Centro, Pistoia, Italy g A.O.U. Pisana, Pisa, Italy h A.O.U. Policlinico di Modena, Italy i A.U.S.L. di Reggio Emilia, Italy j A.O.U Perugia, Italy b
Purpose. The aim of this study is to propose a protocol for DWI QA being easy to implement while still providing quantitative information on relevant parameters for the scanner QC as well as for clinical applications. The measured quantity is the apparent diffusion coefficient (ADC) and its dependence from gradient diffusion direction (Gdd) and phase encoding direction (PED). Methods. A spherical water phantom (14 cm diameter), designed to allow fast and easy measurement of solution temperature, is proposed. The phantom is filled with doped aqueous solution (ADC value certified) and placed at isocentre of scanner. The protocol consists of five set of acquisition of 19 slices, repeated for three orthogonal Gdd. First and second acquisitions are identical, the others differ for the PED and acquisition plane. Each slice (for each Gdd) is acquired with six different b-values varying from 0 s/mm2 to 1000 s/mm2. From each acquisition and Gdd, ADC map of the phantom is generated with monoexponential fit, corrected for temperature and ADC profile along three orthogonal direction is extracted. From first two acquisitions short term reproducibility and SNR are evaluated; second and third acquisitions are used to detect phase encoding direction effects, lasts three maps are used to detect acquisition plane effects on ADC (details in Table 1). Results. A preliminary test of the protocol on 1.5T MRI scanner demonstrated its applicability to routine QA. Relative difference
a
Università di Napoli Federico II, Dipartimento di Fisica ‘‘Ettore Pancini” & INFN Napoli, Italy b Laboratory of Computer Simulations in Medicine, Technical University of Varna, Bulgaria c European Synchrotron Radiation Facility (ESRF), Grenoble, France Purpose. The aim of this work was to explore the available 3D printing technology and available range of printing materials such as resins, polylactic acid, nylon, ABS, etc. in order to determine their complex refractive index properties with respect to those of PMMA and of the breast tissues: adipose, glandular tissue and skin. Methods. Three step wedge phantoms were printed, each consisting of 3 steps with a rectangular area of 20 mm 35 mm for a total of 9 thicknesses ranging from 2 mm to 40 mm. Twenty stereolithographic plastic materials were investigated, including ABS, PLA, PVA, Nylon, Black, Hybrid and PET-G. We performed propagation based phase contrast projection imaging at ESRF (Grenoble, France), beamline ID17 at 30, 45 and 60 keV. Attenuation coefficients (derived from Lambert-Beer law) and refractive index decrements (derived using the Paganin phase retrieval algorithm) were derived in relative terms, with respect to propagation in an equivalent thickness of breast tissues. Results. The absolute difference in percent in terms of the attenuation coefficients and phase shift for different materials with respect to adipose tissue, glandular tissue, skin and PMMA, was measured respectively. Most materials show a difference of less than 5%. Conclusions. Twenty tissue substitute materials were considered as possible candidates to represent PMMA, adipose tissue, glandular tissue and skin. At 30 to 60 keV, the absolute percent difference between the glandular, adipose or skin and the substitute material was less than 5%. PVA material is the best representative for breast tissue and PMMA. https://doi.org/10.1016/j.ejmp.2018.04.251
241. Radiation risk due to medical imaging in long living patients: the case of Hodgkin lymphoma S. Chauvie a, N. Acchiardi b, A. De Maggi a,c, E. Roberto a, F. Bergesio a a
Table 1. Protocol structure and QA evaluated parameters (ST short term variation, CP central/periphery variation, GE gradient diffusion direction variation, PE phase encoding effect, AcP acquisition plane variation). Acquisition 1 2 3 4 5
Acq. Plane Axial Axial Axial Coronal Sagittal
Phase Encoding AP AP LR LR AP
QA parameters ST, CP, SNR, GE ST, PE, SNR CP, PE, AcP, GE CP, AcP, GE CP, AcP, GE
S. Croce e Carle Hospital, Medical Physics, Cuneo, Italy University of Torino, Italy c School of Medical Physics, University of Torino, Italy b
Purpose. Serious concern were risen in the scientific community on the risk of second cancer due to medical imaging in long-living cohort of patients with advanced stage Hodgkin Lymphoma (HL). The purpose of this work was to analyze a cohort of patient enrolled in a clinical trial to understand the type and number of medical