- Email: [email protected]
CT image alignment: Methodology for assessment using a dedicated phantom
256
Abstracts / Physica Medica 56 (2018) 133–278
Table1: Result of analysis Exams (2015-2016)
Mean EDPET Female Male (mSv)
Mean EDCT Female Male (mSv)
Mean EDTOT Female Male (mSv)
Age (years)
Female (n°)
Male (n°)
18
64,6±14,2 (16-95)
2270
2194
4.2 (1,9-8,0)
3.6 (2,1-7,4)
3,6
5,2
7,8
8,8
123
5,9±2,9 (2m-13)
25
29
4,1 (2,6-5,7)
3,7 (0,6-5,8)
3,4
3,6
7,5
7,3
F-FDG PET/CT
I-MIBG SPECT/CT
Figure1: BeirVII cancer- radiation induced risk estimation as a function of gender and age
30–60 mAs, slice thickness of 5 mm, pitch 2 and tube voltage of 110 kV. Whole body scans were assessed by Discovery 710 Elite (GE) PET/CT equipment. The CT acquisitions parameters were as follows: 120 kV tube voltage, 18–60 mAs tube current, 3.75 mm slice width, 0.6 s rotation time. The activities administered to the pts during 4494 18F-FDG PET/CT and 54 123I-MIBG SPECT/CT performed at the Nuclear Medicine Department of the Bufalini Hospital (Cesena) were analyzed by acquiring the data relative to the exams done in 2015– 2016 directly from the digitalized registration system (ASTRIM). The data processing was realized by using a home-made and web-based software implemented in asp language. The values were divided based on patient’s gender, age and weight. Moreover, it was verified how many times and how often the same pt repeated the exam. Eventually, the total mean EDTOT in male and female was calculated with administered activity by using ICRP128 coefficients (mSv/MBq) and from the CT parameters for PET/CT and SPECT/CT with IMPACT software. Table1 shows the results. The 37% of the pts repeated the 123I-MIBG SPECT/CT more than three times in two years, while 27,5% of pts performed two times 18F-FDG PET/CT. Conclusions. The diagnostic procedures involving radiations expose pts to a risk of stochastic cancer related to age and gender (figure1). The fulfil of diagnostic reference values for all scans is mandatory, furthermore the administered activity and CT parameters personalisation for adult and paediatric pts, particularly in repeated acquisitions, is of primary importance – always preserving the image quality. References 1. Quinn B. Radiation dosimetry of 18F-FDG PET-CT: incorporating exam-specific parameters in dose estimates. BMC Med Imag 2016;16:41.
2. Mhiri A. Dosimetry estimation of SPECT/CT for iodine 123-labele dmetaiodobenzylguanidine in children. IJCTO 2015;3(3):323. https://doi.org/10.1016/j.ejmp.2018.04.326
318. PET/CT image alignment: Methodology for assessment using a dedicated phantom C. Spadavecchia, E. De Ponti, S. Morzenti, A. Crespi ASST Monza San Gerardo Hospital, Medical Physics Department, Monza, Italy Purpose. the alignment of transmission and emission images is a crucial requirement in nuclear medicine hybrid scanners (PET/CT and SPECT/CT). EANM and Italian (AIFM-AIMN) guidelines prescribe to perform the alignment test by using specific manufacturer phantoms combined with closed source analysis software packages supplied by the vendor. The purpose of this work was to propose a full independent tool for evaluating CT and PET images alignment by scanning a commercially available phantom. Methods. PET/CT data were acquired on a Discovery-IQ PET/CT system (GE Healthcare, Milwaukee, USA) using a dedicated phantom (PET/CT Phantom, Data Spectrum Corporation). A Matlab code was written to perform image analysis. To evaluate translations, 5 coplanar spheres filled with 18F-FDG radioactive solution were considered through these steps: segmentation of the spheres using a region growing algorithm, calculation of the centre of mass for each sphere and comparison of its coordinates in PET and CT set of images. Rotations were assessed by considering the positioning of 3 aluminium rods filled with radioactive solution in PET and CT: the angles shown in figure were calculated in sagittal, coronal and
Abstracts / Physica Medica 56 (2018) 133–278
axial views. A series of nominal translations (3–5–8–10 mm in the three spatial directions) and rotations (swivel, tilt and roll, 3.2 ° up to 6.8 °) were simulated to validate the method. Results. the sensibility of the method turned out to be less than 1 mm for translations and between 1.0° and 1.7° for rotations. The reproducibility (coefficient of variation over 5 identical acquisitions) was less than 1% both for translations and for rotations. Linearity considered the detected translation/rotation as a function of the nominal one: the angular coefficient for the linear regression ranged from 0.87 (Y-axis translation) to 1.35 (tilt rotation). Conclusions. the method proposed represents an alternative to the use of vendor specific phantoms and software analysis, providing a general validity across each type of scanner. https://doi.org/10.1016/j.ejmp.2018.04.327
319. Effective Dose Assessment on an Hybrid Equipment: Results and challenges to integrate with MDCT G. Tosi a, K. Marzo a, A. Chiti b, F. Zanca c a
Humanitas Research Hospital, Rozzano, Italy Humanitas University, Rozzano, Italy c GE Healthcare, Buc, France b
Purpose. The aim of this study was to measure, monitor and report effective dose in nuclear medicine and to assess current challenges in integrating these measures with CT. Methods. In 2014 we connected a CT-PET to a dose tracking software and started to collect dose data from CT modality; in late 2015 the software was upgraded to a version which includes a nuclear medicine module for dose tracking. Data from the PET part of the scanner, in terms of administered activity and effective dose, were also collected. Results. Data from 12000 CT doses and 3700 PET doses were collected, mostly from: Whole Body (WB) 18F-FDG (63.2%), WB 11CCholine (12.8%), WB 68Ga-DOTATOC (5.5%), Head 11C-Methionine for a total of 18.4% of the whole activity of the scanner. CT mean DLP (mGy⁄cm) data values were (range between brackets): WB 18 F-FDG 1486.3 (76.1-7700.9), WB 11C-Choline 2451.9 (290.95023.1), WB 68Ga-DOTATOC 1183.8 (41.0-3728.4) and Head 11CMethionine 766.7 (52.3-2326.9). Mean effective doses (mSv) were: WB 18F-FDG 15.3 ± 4.7, WB 11C-Choline 26.5 ± 5.6, WB 68Ga 13.4 ± 3.7 and Head 11C-Methionine 1.2 ± 0.7. Mean administered activities (MBq) and effective doses (mSv) for radiopharmaceuticals used in PET were: WB 18F-FDG 335.9-6.4, Head 11C-Methionine 294.6-2.5, WB 68Ga-DOTATOC 168.3-3.5 and WB 11C-Choline 322.2–1.5. The mean total effective doses (mSv) due to both modality were: WB 18 F-FDG 21.7 ± 4.9, Head 11C-Methionine 3.7 ± 0.8, WB 11 C-Choline 27.9 ± 5.6 and WB 68Ga-DOTATOC 16.9 ± 2.8. Conclusions. The implementation of a dose tracking system to nuclear medicine is of great value for accurate and regular recording, reporting and analysis of patient’s effective doses. It can help to improve the evaluation of radiation exposures in the clinical practice. https://doi.org/10.1016/j.ejmp.2018.04.328
257
320. Radioiodine kinetic in small pool hyperthyroid patients C. Canzi a,b, A. D’Alessio c, V. Longari b, F. Buffoni b, I. Martina b, D. Roveretti b, R. Benti b a
Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Medical Physics Dept, Milano, Italy b Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Nuclear Medicine Dept, Milano, Italy c University of Milan, Medical Physics School, Milano, Italy Purpose. Small pool (SP) hyperthyroid patients have a high intrathyroidal radioiodine turnover with a rapid excretion of iodine bound to proteins that circulate into blood and accumulate into liver. The aim of this work was to study the radioiodine kinetic in thyroid, blood, WB and liver in SP patients in comparison to non small pool (NSP) patients and to evaluate contributions of blood selfirradiation and penetrating radiation from WB to mean absorbed dose to blood (Dblood =A0 ) and the dose to the liver. Methods. After pre-therapy dosimetry 10 hyperthyroid patients were classified as SP. After therapeutic administration, blood samples were taken since 0.1 h to 168 h and thyroid and WB images were acquired at 2, 5, 24, 48, 96, 168 h to study iodine kinetic in blood, thyroid, WB and liver. The same study was performed on 4 NSP patients. Results. Thyroid: in SP patients mean uptake at 5 h was higher than at 24 h: 73 ± 6% vs 60 ± 12%; in NSP it was the contrary: 31 ± 12% vs 46 ± 10%. Blood: up to 5 h there was no difference between SP and NSP patients. After 24 h NSP patients presented a continuous decrease of 131I concentration, while in SP ones there was a high increase, in correspondence of thyroid dismission, with slow clearance. Contribution of blood self-irradiation to Dblood =A0 was 0.46 ± 0.20 Gy/ GBq and 0.09 ± 0.06 Gy/GBq for SP and NSP patients (p = 0.004) respectively. WB: there was no difference between SP and NSP patients. Contribution of penetrating radiation from WB to Dblood =A0 was 0.19 ± 0.05 Gy/GBq and 0.16 ± 0.03 Gy/GBq for SP and NSP patients (p = 0.23) respectively. Liver: in NSP patients liver was never visible, in SP patients it was since 24 h. Liver mean dose was 953 ± 721 mGy/GBq. Conclusions. Radioiodine kinetic in SP hyperthyroid patients is different from NSP ones: in thyroid, uptake is higher at 5 h than at 24 h; in blood, after an initial fast clearance, there is an increment of concentration at 24 h; in WB scans liver is visible since 24 h and so it is self-irradiated by radioiodine; contribution of blood self-irradiation to Dblood =A0 is higher than that from penetrating radiation from WB. https://doi.org/10.1016/j.ejmp.2018.04.329
321. Role of Diagnostic Reference Levels (DRLs) in Nuclear Medicine: The experience of INT Pascale in Naples L. D’Ambrosio, P. Gaballo, A. Prisco, F. Di Gennaro, S. Lastoria Istituto Nazionale Tumori IRCCS Pascale, Medicina Nucleare, Napoli, Italy Purpose. DRLs provide guidance regarding appropriate or conventional levels of radiation dose to be delivered to patients. DRLs
Abstracts / Physica Medica 56 (2018) 133–278
Table1: Result of analysis Exams (2015-2016)
Mean EDPET Female Male (mSv)
Mean EDCT Female Male (mSv)
Mean EDTOT Female Male (mSv)
Age (years)
Female (n°)
Male (n°)
18
64,6±14,2 (16-95)
2270
2194
4.2 (1,9-8,0)
3.6 (2,1-7,4)
3,6
5,2
7,8
8,8
123
5,9±2,9 (2m-13)
25
29
4,1 (2,6-5,7)
3,7 (0,6-5,8)
3,4
3,6
7,5
7,3
F-FDG PET/CT
I-MIBG SPECT/CT
Figure1: BeirVII cancer- radiation induced risk estimation as a function of gender and age
30–60 mAs, slice thickness of 5 mm, pitch 2 and tube voltage of 110 kV. Whole body scans were assessed by Discovery 710 Elite (GE) PET/CT equipment. The CT acquisitions parameters were as follows: 120 kV tube voltage, 18–60 mAs tube current, 3.75 mm slice width, 0.6 s rotation time. The activities administered to the pts during 4494 18F-FDG PET/CT and 54 123I-MIBG SPECT/CT performed at the Nuclear Medicine Department of the Bufalini Hospital (Cesena) were analyzed by acquiring the data relative to the exams done in 2015– 2016 directly from the digitalized registration system (ASTRIM). The data processing was realized by using a home-made and web-based software implemented in asp language. The values were divided based on patient’s gender, age and weight. Moreover, it was verified how many times and how often the same pt repeated the exam. Eventually, the total mean EDTOT in male and female was calculated with administered activity by using ICRP128 coefficients (mSv/MBq) and from the CT parameters for PET/CT and SPECT/CT with IMPACT software. Table1 shows the results. The 37% of the pts repeated the 123I-MIBG SPECT/CT more than three times in two years, while 27,5% of pts performed two times 18F-FDG PET/CT. Conclusions. The diagnostic procedures involving radiations expose pts to a risk of stochastic cancer related to age and gender (figure1). The fulfil of diagnostic reference values for all scans is mandatory, furthermore the administered activity and CT parameters personalisation for adult and paediatric pts, particularly in repeated acquisitions, is of primary importance – always preserving the image quality. References 1. Quinn B. Radiation dosimetry of 18F-FDG PET-CT: incorporating exam-specific parameters in dose estimates. BMC Med Imag 2016;16:41.
2. Mhiri A. Dosimetry estimation of SPECT/CT for iodine 123-labele dmetaiodobenzylguanidine in children. IJCTO 2015;3(3):323. https://doi.org/10.1016/j.ejmp.2018.04.326
318. PET/CT image alignment: Methodology for assessment using a dedicated phantom C. Spadavecchia, E. De Ponti, S. Morzenti, A. Crespi ASST Monza San Gerardo Hospital, Medical Physics Department, Monza, Italy Purpose. the alignment of transmission and emission images is a crucial requirement in nuclear medicine hybrid scanners (PET/CT and SPECT/CT). EANM and Italian (AIFM-AIMN) guidelines prescribe to perform the alignment test by using specific manufacturer phantoms combined with closed source analysis software packages supplied by the vendor. The purpose of this work was to propose a full independent tool for evaluating CT and PET images alignment by scanning a commercially available phantom. Methods. PET/CT data were acquired on a Discovery-IQ PET/CT system (GE Healthcare, Milwaukee, USA) using a dedicated phantom (PET/CT Phantom, Data Spectrum Corporation). A Matlab code was written to perform image analysis. To evaluate translations, 5 coplanar spheres filled with 18F-FDG radioactive solution were considered through these steps: segmentation of the spheres using a region growing algorithm, calculation of the centre of mass for each sphere and comparison of its coordinates in PET and CT set of images. Rotations were assessed by considering the positioning of 3 aluminium rods filled with radioactive solution in PET and CT: the angles shown in figure were calculated in sagittal, coronal and
Abstracts / Physica Medica 56 (2018) 133–278
axial views. A series of nominal translations (3–5–8–10 mm in the three spatial directions) and rotations (swivel, tilt and roll, 3.2 ° up to 6.8 °) were simulated to validate the method. Results. the sensibility of the method turned out to be less than 1 mm for translations and between 1.0° and 1.7° for rotations. The reproducibility (coefficient of variation over 5 identical acquisitions) was less than 1% both for translations and for rotations. Linearity considered the detected translation/rotation as a function of the nominal one: the angular coefficient for the linear regression ranged from 0.87 (Y-axis translation) to 1.35 (tilt rotation). Conclusions. the method proposed represents an alternative to the use of vendor specific phantoms and software analysis, providing a general validity across each type of scanner. https://doi.org/10.1016/j.ejmp.2018.04.327
319. Effective Dose Assessment on an Hybrid Equipment: Results and challenges to integrate with MDCT G. Tosi a, K. Marzo a, A. Chiti b, F. Zanca c a
Humanitas Research Hospital, Rozzano, Italy Humanitas University, Rozzano, Italy c GE Healthcare, Buc, France b
Purpose. The aim of this study was to measure, monitor and report effective dose in nuclear medicine and to assess current challenges in integrating these measures with CT. Methods. In 2014 we connected a CT-PET to a dose tracking software and started to collect dose data from CT modality; in late 2015 the software was upgraded to a version which includes a nuclear medicine module for dose tracking. Data from the PET part of the scanner, in terms of administered activity and effective dose, were also collected. Results. Data from 12000 CT doses and 3700 PET doses were collected, mostly from: Whole Body (WB) 18F-FDG (63.2%), WB 11CCholine (12.8%), WB 68Ga-DOTATOC (5.5%), Head 11C-Methionine for a total of 18.4% of the whole activity of the scanner. CT mean DLP (mGy⁄cm) data values were (range between brackets): WB 18 F-FDG 1486.3 (76.1-7700.9), WB 11C-Choline 2451.9 (290.95023.1), WB 68Ga-DOTATOC 1183.8 (41.0-3728.4) and Head 11CMethionine 766.7 (52.3-2326.9). Mean effective doses (mSv) were: WB 18F-FDG 15.3 ± 4.7, WB 11C-Choline 26.5 ± 5.6, WB 68Ga 13.4 ± 3.7 and Head 11C-Methionine 1.2 ± 0.7. Mean administered activities (MBq) and effective doses (mSv) for radiopharmaceuticals used in PET were: WB 18F-FDG 335.9-6.4, Head 11C-Methionine 294.6-2.5, WB 68Ga-DOTATOC 168.3-3.5 and WB 11C-Choline 322.2–1.5. The mean total effective doses (mSv) due to both modality were: WB 18 F-FDG 21.7 ± 4.9, Head 11C-Methionine 3.7 ± 0.8, WB 11 C-Choline 27.9 ± 5.6 and WB 68Ga-DOTATOC 16.9 ± 2.8. Conclusions. The implementation of a dose tracking system to nuclear medicine is of great value for accurate and regular recording, reporting and analysis of patient’s effective doses. It can help to improve the evaluation of radiation exposures in the clinical practice. https://doi.org/10.1016/j.ejmp.2018.04.328
257
320. Radioiodine kinetic in small pool hyperthyroid patients C. Canzi a,b, A. D’Alessio c, V. Longari b, F. Buffoni b, I. Martina b, D. Roveretti b, R. Benti b a
Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Medical Physics Dept, Milano, Italy b Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Nuclear Medicine Dept, Milano, Italy c University of Milan, Medical Physics School, Milano, Italy Purpose. Small pool (SP) hyperthyroid patients have a high intrathyroidal radioiodine turnover with a rapid excretion of iodine bound to proteins that circulate into blood and accumulate into liver. The aim of this work was to study the radioiodine kinetic in thyroid, blood, WB and liver in SP patients in comparison to non small pool (NSP) patients and to evaluate contributions of blood selfirradiation and penetrating radiation from WB to mean absorbed dose to blood (Dblood =A0 ) and the dose to the liver. Methods. After pre-therapy dosimetry 10 hyperthyroid patients were classified as SP. After therapeutic administration, blood samples were taken since 0.1 h to 168 h and thyroid and WB images were acquired at 2, 5, 24, 48, 96, 168 h to study iodine kinetic in blood, thyroid, WB and liver. The same study was performed on 4 NSP patients. Results. Thyroid: in SP patients mean uptake at 5 h was higher than at 24 h: 73 ± 6% vs 60 ± 12%; in NSP it was the contrary: 31 ± 12% vs 46 ± 10%. Blood: up to 5 h there was no difference between SP and NSP patients. After 24 h NSP patients presented a continuous decrease of 131I concentration, while in SP ones there was a high increase, in correspondence of thyroid dismission, with slow clearance. Contribution of blood self-irradiation to Dblood =A0 was 0.46 ± 0.20 Gy/ GBq and 0.09 ± 0.06 Gy/GBq for SP and NSP patients (p = 0.004) respectively. WB: there was no difference between SP and NSP patients. Contribution of penetrating radiation from WB to Dblood =A0 was 0.19 ± 0.05 Gy/GBq and 0.16 ± 0.03 Gy/GBq for SP and NSP patients (p = 0.23) respectively. Liver: in NSP patients liver was never visible, in SP patients it was since 24 h. Liver mean dose was 953 ± 721 mGy/GBq. Conclusions. Radioiodine kinetic in SP hyperthyroid patients is different from NSP ones: in thyroid, uptake is higher at 5 h than at 24 h; in blood, after an initial fast clearance, there is an increment of concentration at 24 h; in WB scans liver is visible since 24 h and so it is self-irradiated by radioiodine; contribution of blood self-irradiation to Dblood =A0 is higher than that from penetrating radiation from WB. https://doi.org/10.1016/j.ejmp.2018.04.329
321. Role of Diagnostic Reference Levels (DRLs) in Nuclear Medicine: The experience of INT Pascale in Naples L. D’Ambrosio, P. Gaballo, A. Prisco, F. Di Gennaro, S. Lastoria Istituto Nazionale Tumori IRCCS Pascale, Medicina Nucleare, Napoli, Italy Purpose. DRLs provide guidance regarding appropriate or conventional levels of radiation dose to be delivered to patients. DRLs