Temat: NEMA phantom - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: The influence of Q.Clear reconstruction on the contrast recovery coefficient and semi-quantitative parameters of NEMA phantom imaging
Autorzy:: Sowa-Staszczak, Anna
Skórkiewicz, Konrad
Łątka, Kazimierz
Hubalewska-Dydejczyk, Alicja
Opis:: Background: The aim of the study is to optimize value of B parameter (β) which is used in the Q.Clear reconstruction in the imaging of neuroendocrine tumours. The study is divided into two parts: analysis of phantom data aiming selection of the appropriate β for small changes, and then assessment of its impact on the quality of patients' image. The literature data on the optimal β value are inconclusive. What is more the suggested values are not the result of the semi-quantitative assessment of Standard Uptake Volume (SUV) and the proper verification based e.g. on phantom studies using the known activity. Results: The obtained results show that β increase increases the image uniformity in the Q.Clear reconstruction algorithm. Also referring to the scientific reports, one can see that the signal to noise ratio in the image increases. The effect of the β change on the SUV mean and Contrast Recovery Coefficient (CRC) value is the largest for the smallest objects. The decrease of this parameter is much higher also with the lower values of the activity (lower counts statistic in PET system). Conclusions: An increase of β has an adverse effect on the quality of semi-quantitative assessment of SUV - as the parameter increases, the SUV and CRC values decrease. In the visual assessment, a satisfactory image quality is present with β=450. Based on the analysis of SUV and CRC, an appropriate range of β values was selected as 350-450. At the selected range, a retrospective analysis of the clinical images of neuroendocrine tumours will be performed in the future and the impact of the change on the semi-quantitative analysis of pathological changes will be verified.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Tytuł:: Wyznaczanie czynnika kalibracyjnego SF na potrzeby dozymetrii indywidualnej pacjentów poddanych terapii guzów neuroendokrynnych (NET) z zastosowaniem [177Lu]Lu- DOTA-TATE lub mieszanek [90Y+177Lu]Y+Lu-DOTA-TATE
Determination of the SF calibration factor for individual dosimetry of patients undergoing neuroendocrine tumor therapy (NET) using [177Lu]Lu- DOTA-TATE or [90Y+177Lu]Y+Lu-DOTA-TATE
Autorzy:: Chalewska, Wioletta
Cegła, Paulina
Sackiewicz, Agata
Dedecjus, Marek
Tematy:: czynnik kalibracyjny
terapia izotopowa
NEMA fantom
calibration factor
theragnostics
NEMA phantom; Pokaż więcej
Wydawca:: Indygo Zahir Media
Powiązania:: https://bibliotekanauki.pl/articles/58906545.pdf Link otwiera się w nowym oknie
Opis:: Cel. Celem pracy było wyznaczenie czynnika kalibracyjnego SF u pacjentów poddanych terapii guzów neuroendokrynnych (NET) z zastosowaniem [177Lu]Lu-DOTA-TATE lub mieszanek [90Y+177Lu]Y+Lu-DOTA-TATE. Materiał i metody. Analizę przeprowadzono przy użyciu fantomu NEMA wypełnionego aktywnością 3800 MBq izotopu 177Lu oraz mieszankę izotopów [90Y+177Lu]Y+Lu-DOTA-TATE. Wszystkie badania zostały zrealizowane na aparacie Discovery NM/CT 670 firmy GE, natomiast rekonstrukcje przeprowadzono przy użyciu oprogramowania Volumetrix MI. Wyniki. Uzyskane wartości czynnika kalibracyjnego SF (Bq/cps) pierwszego dnia analizy dla izotopu 177Lu o aktywności 3800 MBq wyniosły 185 592 Bq/cps, a ostatniego dnia przy aktywności 177Lu 1848,68 MBq – 181 465 Bq/cps. Dla mieszanki izotopów uwzględniono zmieniający się stosunek aktywności izotopu 177Lu do 90Y (A = 177Lu/90Y), który pierwszego dnia wynosił 0,94, a ostatniego 54,84. Wartości SF ulegały zmianie wraz z czasem rozpadu izotopów oraz zmianą stosunków ich aktywności. Wnioski. Uzyskane wartości czynnika kalibracyjnego są charakterystyczne dla danej gamma kamery, na której przeprowadzane są badania, stąd, by uzyskać wiarygodne pomiary dozymetryczne, niezbędne jest wcześniejsze wykonanie badań fantomowych.
Objective. The aim of this study was to assess the calibration factor (SF) for the [177 Lu]Lu- DOTA-TATE or [90 Y+177 Lu] Y+Lu-DOTA-TATE in patients with neuroendocrine tumors (NET). Material and methods. For the analysis the NEMA Phantom filled with 177 Lu with activity of 3800 MBq and the [90 Y+177 Lu] Y+Lu-DOTA-TATE was used. Studies were performed on a Discovery NM/CT 670, while for the reconstruction Volumetric MI Software was used. Results. SF for 177 Lu in the first day was 185 592 Bq/cps, while on the last day (with activity of 1848,68 MBq) was 181 465 Bq/cps. For the [90 Y+177 Lu]Y+Lu-DOTA-TATE, changing in the activity 177 Lu to 90Y (A=177 Lu/90 Y) was applied. On the first day was A=0,94, while on the last day A = 54,84. The SF values changed depends on the half time of the isotopes and the ratio of their activity. Conclusions. Obtained results for the SF are characteristic for the gammacamera on which studies were performed, therefore, to obtain the reliable dosimetric results, first the Phantom studies should be performed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: First positronium lifetime imaging with scandium-44 on a long axial field-of-view PET/CT
Autorzy:: Mercolli, Lorenzo
van der Meulen, Nicholas P.
Schibli, Roger
Seifert, Robert
Moiseeva, Anzhelika
Stępień, Ewa
Steinberger, William M.
Moskal, Paweł
Rathod, Narendra
Sari, Hasan
Conti, Maurizio
Grundler, Pascal V.
Shi, Kuangyu
Braccini, Saverio
Rominger, Axel
Opis:: 4Purpose: The physical properties of $^{44}$Sc, combined with its imminent clinical application, position it as a prime candidate for in vivo positronium lifetime imaging. In this study, we investigate the count statistics for ortho-positronium (oPs) measurements with $^{44}$Sc on a commercial long-axial field-of-view (LAFOV) PET/CT. Method: A NEMA image quality phantom was filled with 41.7 MBq of $^{44}$Sc dissolved in water and scanned on a LAFOV PET/CT. Three-photon events were identified using a prototype feature of the scanner and dedicated software. The lifetime of oPs was determined in the phantom spheres and in 4 $\times$ 4 $\times$ 4 mm$^{3}$ voxels. Results: All measured oPs lifetimes are compatible, within the uncertainties, with the literature values for water. The oPs lifetime is 2.65 ± 0.50, 1.39 ± 0.20 and 1.76 ± 0.18 ns in the three smallest spheres of the phantom and 1.79 ± 0.57 ns for a single voxel in the central region of the largest sphere. The relative standard deviation in the background regions of the time difference distributions, i.e., for time differences smaller than -2.7 ns, is above 20%—even for voxels inside the phantom spheres. Conclusions: Despite the favorable physical properties of $^{44}$Sc, the count statistics of three-photon events remains a challenge. The high prompt-photon energy causes a significant amount of random three-photon coincidences with the given methodology and, therefore, increases the statistical uncertainties on the measured oPs lifetime.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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