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271. Digital breast tomosynthesis with photon counting technology: Dosimetric data from a preliminary clinical comparison study.
Abstracts / Physica Medica 56 (2018) 133–278
229
Table 1 Table. 1. Entrance surface Kerma T1 e T2, T1 COR%, T2 COR%.
Elbow AP-obl Elbow Lateral Wrist PA Wirst Lateral Hand PA Hand Oblique Knee AP Knee LL Ankle AP Ankle Lateral Ankle Oblique Foot AP Foot Lateral Foot Oblique
T1 Ka (lGy)
T2 Ka (lGy)
S% Ka
T1 COR%
T2 COR%
98.1 100.1 84.8 108 66.4 74.3 276.5 240.9 154.1 179.2 168.7 165.2 169.1 168.8
129.7 145.3 99.7 128.4 75.2 107.1 281.3 262.6 160.6 157.2 165.6 98.3 96.3 98.3
32 45 18 19 13 44 2 9 4 12 2 40 43 42
56
70
65
74
66
77
54
69
58
75
59
73
Conclusions. Both techniques give good results in terms of dosage and quality. However, it is possible to improve the image quality, without excessive dose increase to the patient by changing and optimising acquisition parameters. References 1. Hess R, Manke D, Neitzel U. Optimizing imagine quality and dose for digital radiography of paediatric extremities. Eur Soc Radiol 2012. 2. Bijkerk KR, Thijssen MAO, Arnoldussen ThJM, Manual CDMAMphantom type 3.4. University Medical Centre Nijimegen St Radbound. 2002:1–16.
1.81 mGy for CS with a 57% mean AGD reduction. The mean LCC AGD was 0.72 mGy for PC and 1.5 mGy for CS with a 50% mean AGD reduction. The mean LMLO AGD was 0.75 mGy for PC and 1.72 mGy for CS with a 55% mean dose reduction. Also considering small compression differences, we found a minimum of 50% dose reduction and a correlation between dose reduction and breast thickness: large breasts seem to benefit more from PCD AGD reduction. The doses delivered to the contralateral breast with the PCD device were up to 85% lower than that delivered with the CTS. The highest differences were relative to the nipple area. Conclusions. Our results demonstrate that PCD tomosynthesis allows a significant dose reduction especially in large breasts and a sensible reduction of dose delivered to the contralateral breast.
https://doi.org/10.1016/j.ejmp.2018.04.280 https://doi.org/10.1016/j.ejmp.2018.04.281
271. Digital breast tomosynthesis with photon counting technology: Dosimetric data from a preliminary clinical comparison study. A. del Vecchio a, A. Loria a, E. Venturini b, P. Panizza b, P. Signorotto a a
IRCCS San Raffaele Scientific Institute, Medical Physics Department, Milan, Italy b IRCCS San Raffaele Scientific Institute, Breast Radiology Department, Milan, Italy Purpose. The aim is to compare the Average Glandular Dose (AGD) of a photon counting detector (PCD) digital breast tomosynthesis prototype with those of a conventional tomosynthesis system (CTS). Methods. After ethical committee approval, some consenting women older than 40y with highly suspicious breast finding at clinical or imaging evaluation (BIRADS 4c-5) underwent bilateral 2-view tomosynthesis with a CTS and a PCD prototype before breast biopsy. AGD and breast thickness were recorded and compared. To verify the correspondence between displayed and measured dose, a set of measurements was done following the EUREF protocol. Furthermore, entrance surface dose to the contralateral breast was evaluated with 21 thermoluminescent dosimeters placed on a anthropomorphic phantom Alderson RANDO simulating an adult female. Results. 16 women (mean age 70 y; 44–82 y) underwent bilateral 2-view tomosynthesis with both systems. The mean RCC displayed AGD was 0.75 mGy for PC and 1.61 mGy for CS with a 51% mean AGD reduction. The mean RMLO AGD was 0.77 mGy for PC and
272. Digital Breast Tomosynthesis Index (DBTI): A score to evaluate Digital Breast Tomosynthesis (DBT) device. A. Loria a, P. Signorotto a, E. Venturini b, P. Panizza b, A. del Vecchio a a IRCCS San Raffaele Scientific Institute, Medical Physics Department, Milan, Italy b IRCCS San Raffaele Scientific Institute, Breast Radiology Department, Milan, Italy
Purpose. The aim of this study is to combine image quality (IQ) and dosimetric parameters into a score to evaluate the goodness of a digital breast tomosynthesis (DBT) device. Methods. Digital Breast Tomosynthesis Index (DBTI) is derived from two figure of merit (FoM) introduced to evaluate CT devices (Rose and ImPACT) [1]. These FoMs include parameters as contrast-to-noise ratio (CNR), spatial resolution in terms of modulation transfer function (MTF), slice thickness and a dosimetric quantity (CTDI). In the same way, DBTI is designed to have a quadratic dependence from signal-difference-to-noise ratio (SDNR), cubical dependence from the MTF, and to be inversely proportional to slicesensitivity profile (SSP) and average glandular dose (AGD). IQ parameters were measured using the Tomophan phantom. SDNR was evaluated with the 0.2 mm thick aluminum insert. MTF was calculated for scan and sub-scan directions from the point spread function of the 0.18 mm tungsten bead. SSP evaluation was performed with the two reversing angled bead ramps method. These parameters were
229
Table 1 Table. 1. Entrance surface Kerma T1 e T2, T1 COR%, T2 COR%.
Elbow AP-obl Elbow Lateral Wrist PA Wirst Lateral Hand PA Hand Oblique Knee AP Knee LL Ankle AP Ankle Lateral Ankle Oblique Foot AP Foot Lateral Foot Oblique
T1 Ka (lGy)
T2 Ka (lGy)
S% Ka
T1 COR%
T2 COR%
98.1 100.1 84.8 108 66.4 74.3 276.5 240.9 154.1 179.2 168.7 165.2 169.1 168.8
129.7 145.3 99.7 128.4 75.2 107.1 281.3 262.6 160.6 157.2 165.6 98.3 96.3 98.3
32 45 18 19 13 44 2 9 4 12 2 40 43 42
56
70
65
74
66
77
54
69
58
75
59
73
Conclusions. Both techniques give good results in terms of dosage and quality. However, it is possible to improve the image quality, without excessive dose increase to the patient by changing and optimising acquisition parameters. References 1. Hess R, Manke D, Neitzel U. Optimizing imagine quality and dose for digital radiography of paediatric extremities. Eur Soc Radiol 2012. 2. Bijkerk KR, Thijssen MAO, Arnoldussen ThJM, Manual CDMAMphantom type 3.4. University Medical Centre Nijimegen St Radbound. 2002:1–16.
1.81 mGy for CS with a 57% mean AGD reduction. The mean LCC AGD was 0.72 mGy for PC and 1.5 mGy for CS with a 50% mean AGD reduction. The mean LMLO AGD was 0.75 mGy for PC and 1.72 mGy for CS with a 55% mean dose reduction. Also considering small compression differences, we found a minimum of 50% dose reduction and a correlation between dose reduction and breast thickness: large breasts seem to benefit more from PCD AGD reduction. The doses delivered to the contralateral breast with the PCD device were up to 85% lower than that delivered with the CTS. The highest differences were relative to the nipple area. Conclusions. Our results demonstrate that PCD tomosynthesis allows a significant dose reduction especially in large breasts and a sensible reduction of dose delivered to the contralateral breast.
https://doi.org/10.1016/j.ejmp.2018.04.280 https://doi.org/10.1016/j.ejmp.2018.04.281
271. Digital breast tomosynthesis with photon counting technology: Dosimetric data from a preliminary clinical comparison study. A. del Vecchio a, A. Loria a, E. Venturini b, P. Panizza b, P. Signorotto a a
IRCCS San Raffaele Scientific Institute, Medical Physics Department, Milan, Italy b IRCCS San Raffaele Scientific Institute, Breast Radiology Department, Milan, Italy Purpose. The aim is to compare the Average Glandular Dose (AGD) of a photon counting detector (PCD) digital breast tomosynthesis prototype with those of a conventional tomosynthesis system (CTS). Methods. After ethical committee approval, some consenting women older than 40y with highly suspicious breast finding at clinical or imaging evaluation (BIRADS 4c-5) underwent bilateral 2-view tomosynthesis with a CTS and a PCD prototype before breast biopsy. AGD and breast thickness were recorded and compared. To verify the correspondence between displayed and measured dose, a set of measurements was done following the EUREF protocol. Furthermore, entrance surface dose to the contralateral breast was evaluated with 21 thermoluminescent dosimeters placed on a anthropomorphic phantom Alderson RANDO simulating an adult female. Results. 16 women (mean age 70 y; 44–82 y) underwent bilateral 2-view tomosynthesis with both systems. The mean RCC displayed AGD was 0.75 mGy for PC and 1.61 mGy for CS with a 51% mean AGD reduction. The mean RMLO AGD was 0.77 mGy for PC and
272. Digital Breast Tomosynthesis Index (DBTI): A score to evaluate Digital Breast Tomosynthesis (DBT) device. A. Loria a, P. Signorotto a, E. Venturini b, P. Panizza b, A. del Vecchio a a IRCCS San Raffaele Scientific Institute, Medical Physics Department, Milan, Italy b IRCCS San Raffaele Scientific Institute, Breast Radiology Department, Milan, Italy
Purpose. The aim of this study is to combine image quality (IQ) and dosimetric parameters into a score to evaluate the goodness of a digital breast tomosynthesis (DBT) device. Methods. Digital Breast Tomosynthesis Index (DBTI) is derived from two figure of merit (FoM) introduced to evaluate CT devices (Rose and ImPACT) [1]. These FoMs include parameters as contrast-to-noise ratio (CNR), spatial resolution in terms of modulation transfer function (MTF), slice thickness and a dosimetric quantity (CTDI). In the same way, DBTI is designed to have a quadratic dependence from signal-difference-to-noise ratio (SDNR), cubical dependence from the MTF, and to be inversely proportional to slicesensitivity profile (SSP) and average glandular dose (AGD). IQ parameters were measured using the Tomophan phantom. SDNR was evaluated with the 0.2 mm thick aluminum insert. MTF was calculated for scan and sub-scan directions from the point spread function of the 0.18 mm tungsten bead. SSP evaluation was performed with the two reversing angled bead ramps method. These parameters were