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331. Performance of point spread function reconstruction algorithm on a new PET-CT TOF scanner
Abstracts / Physica Medica 56 (2018) 133–278
dose values in BED (p = 0.0049): the Area-under-curve (AUC) was 0.758 and 0.770, respectively. No significant differences were observed for the healing probability between the BED- or absorbed dose-based treatments (p = 0.423). Considering the total 187 dosimetry-based treatments, the absorbed dose/BED-response curves showed regular trends with r-value of 0.979 and 0.977, respectively. The absorbed dose associated to a healing probability of 50% and 95%, was 42.6 Gy and 242.3 Gy, respectively. The probability of recurrence was 9.6%, exactly half of that associated to the empiric treatment group (19.3%, p = 0.0081). Conclusions. Patient-specific dosimetry has proven to increase therapeutic effectiveness, reducing the recurrence frequency and the need of repeated treatments. https://doi.org/10.1016/j.ejmp.2018.04.339
263
Results. PSF images showed resolution higher (e.g. 3 mm for 30 iterations) than the standard OSEM (6 mm). As shown in figure 1a the more iteration number the higher artifacts presence, especially in the background region. MV and SD values relative to the ‘‘hot spheres” strongly depend on iteration number and regularization level; variations up to +1000% were found (500 iterations and 20 regularization) both on MV and SD values. No variations were noticed on background MV, but SD values increase up to +600%. As consequence SNR and CNR are affected by reconstruction parameters (Fig. 1b). Conclusions. PSF images showed resolution higher than standard OSEM, but also huge artifacts and unacceptable variations in measured activity (and SUV). The use of PSF reconstruction for quantitative purposes is not recommended and its use should be designed for specific uses. https://doi.org/10.1016/j.ejmp.2018.04.340
331. Performance of point spread function reconstruction algorithm on a new PET-CT TOF scanner M. Poli a, E. Richetta a, C. Cutaia a, M. Pasquino a, E. Garnero b, R.E. Pellerito b, M. Stasi a a b
A.O. Ordine Mauriziano, Medical Physics Department, Turin, Italy A.O. Ordine Mauriziano, Nuclear Medicine Department, Turin, Italy
Purpose. Aim of this study was to evaluate the performance of PSF reconstruction algorithm of a PET-TC TOF scanner. Comparison in term of image quality was performed in order to investigate potentialities and differences between PSF algorithm and the standard OSEM algorithm routinely applied in the clinical use. Methods. The phantom NEMA 2012 Body Image Quality (18F, 213 kBq/ml, h 10 mm 13 mm 17 mm 22 mm hot spheres (background ratio 4 1), h 28 mm 37 mm cold spheres) was acquired with Philips IngenuityTF PET-TC scanner (TOF, AC-SC). Raw data were reconstructed both with standard OSEM 3D and with PSF, using 20 different paired iteration values (1–500) and regularization levels (1–20). Seven regions of interest (ROIs) were contoured: 4 centred on ‘‘hot” spheres, 2 on ‘‘cold” spheres and 1 on background. Mean value (MV) and standard deviation (SD) of every ROI were calculated: signal to noise ratio (SNR) and contrast to noise ratio (CNR) were compared. Spatial resolution was evaluated as steepness of the 10 mm-sphere profile.
332. Metastatic bone volume dose estimation procedure in 223Ra-Xofigo treatments A. Ostinelli, M. Duchini, M. Cacciatori, M. Frigerio, G. Frigerio ASST Lariana, UOC Fisica Sanitaria, Como, Italy Purpose. 223Ra-dichloride (BAYER Xofigo) radiometabolic therapy of bone metastatic lesions of castration-resistant prostate cancer seems to offer a valid alternative to conventional approaches, due to the alpha particles emitted in the tumor site. While a specific approach was developed to identify proper criteria for the
t½ eff
4.73
d
Volume loc.
118
cm3
Radius loc.
3.04
cm
A0
0.35
MBq
Ã
209
GBq s
dose values in BED (p = 0.0049): the Area-under-curve (AUC) was 0.758 and 0.770, respectively. No significant differences were observed for the healing probability between the BED- or absorbed dose-based treatments (p = 0.423). Considering the total 187 dosimetry-based treatments, the absorbed dose/BED-response curves showed regular trends with r-value of 0.979 and 0.977, respectively. The absorbed dose associated to a healing probability of 50% and 95%, was 42.6 Gy and 242.3 Gy, respectively. The probability of recurrence was 9.6%, exactly half of that associated to the empiric treatment group (19.3%, p = 0.0081). Conclusions. Patient-specific dosimetry has proven to increase therapeutic effectiveness, reducing the recurrence frequency and the need of repeated treatments. https://doi.org/10.1016/j.ejmp.2018.04.339
263
Results. PSF images showed resolution higher (e.g. 3 mm for 30 iterations) than the standard OSEM (6 mm). As shown in figure 1a the more iteration number the higher artifacts presence, especially in the background region. MV and SD values relative to the ‘‘hot spheres” strongly depend on iteration number and regularization level; variations up to +1000% were found (500 iterations and 20 regularization) both on MV and SD values. No variations were noticed on background MV, but SD values increase up to +600%. As consequence SNR and CNR are affected by reconstruction parameters (Fig. 1b). Conclusions. PSF images showed resolution higher than standard OSEM, but also huge artifacts and unacceptable variations in measured activity (and SUV). The use of PSF reconstruction for quantitative purposes is not recommended and its use should be designed for specific uses. https://doi.org/10.1016/j.ejmp.2018.04.340
331. Performance of point spread function reconstruction algorithm on a new PET-CT TOF scanner M. Poli a, E. Richetta a, C. Cutaia a, M. Pasquino a, E. Garnero b, R.E. Pellerito b, M. Stasi a a b
A.O. Ordine Mauriziano, Medical Physics Department, Turin, Italy A.O. Ordine Mauriziano, Nuclear Medicine Department, Turin, Italy
Purpose. Aim of this study was to evaluate the performance of PSF reconstruction algorithm of a PET-TC TOF scanner. Comparison in term of image quality was performed in order to investigate potentialities and differences between PSF algorithm and the standard OSEM algorithm routinely applied in the clinical use. Methods. The phantom NEMA 2012 Body Image Quality (18F, 213 kBq/ml, h 10 mm 13 mm 17 mm 22 mm hot spheres (background ratio 4 1), h 28 mm 37 mm cold spheres) was acquired with Philips IngenuityTF PET-TC scanner (TOF, AC-SC). Raw data were reconstructed both with standard OSEM 3D and with PSF, using 20 different paired iteration values (1–500) and regularization levels (1–20). Seven regions of interest (ROIs) were contoured: 4 centred on ‘‘hot” spheres, 2 on ‘‘cold” spheres and 1 on background. Mean value (MV) and standard deviation (SD) of every ROI were calculated: signal to noise ratio (SNR) and contrast to noise ratio (CNR) were compared. Spatial resolution was evaluated as steepness of the 10 mm-sphere profile.
332. Metastatic bone volume dose estimation procedure in 223Ra-Xofigo treatments A. Ostinelli, M. Duchini, M. Cacciatori, M. Frigerio, G. Frigerio ASST Lariana, UOC Fisica Sanitaria, Como, Italy Purpose. 223Ra-dichloride (BAYER Xofigo) radiometabolic therapy of bone metastatic lesions of castration-resistant prostate cancer seems to offer a valid alternative to conventional approaches, due to the alpha particles emitted in the tumor site. While a specific approach was developed to identify proper criteria for the
t½ eff
4.73
d
Volume loc.
118
cm3
Radius loc.
3.04
cm
A0
0.35
MBq
Ã
209
GBq s