This study aims to evaluate the dependence of 4D-PET data sorting on the number of phases in which the respiratory cycle can be divided. The issue is to find the best compromise to reduce the conflicting effects induced by increasing the number of phases: lesion motion on each set of images decreases, but on the other hand image noise increases. The IQ NEMA 2001 IEC body phantom was used to simulate the movement of neoplastic lesions in the thorax and abdomen, investigating the effect of: target size (10 37 mm), lesion-to-background activity concentration ratio (4:1 and 8:1), total acquisition time (3, 6, 12, 20 min), and number of phase partitions (1, 2, 4, 6, 8, 10, 13). The phantom was moved in a cranial-caudal direction with an excursion of 25 mm and a period of 4.0 sec. Five parameters associated to lesion volume and activity concentration were considered to assess the capability of the 4D-PET technique to “freeze” the phantom motion. The results for all the parameters showed the capability of the 4D-PET acquisition technique to “freeze” the lesion motion. The division into six phases was found to be the best compromise between temporal resolution and image noise for the phase where the “lesions” move faster; whereas the partition into four phases could be used if a stable breathing phase is considered.
4D-PET data sorting into different number of phases: a NEMA IQ phantom study
Mancosu P;
2009-01-01
Abstract
This study aims to evaluate the dependence of 4D-PET data sorting on the number of phases in which the respiratory cycle can be divided. The issue is to find the best compromise to reduce the conflicting effects induced by increasing the number of phases: lesion motion on each set of images decreases, but on the other hand image noise increases. The IQ NEMA 2001 IEC body phantom was used to simulate the movement of neoplastic lesions in the thorax and abdomen, investigating the effect of: target size (10 37 mm), lesion-to-background activity concentration ratio (4:1 and 8:1), total acquisition time (3, 6, 12, 20 min), and number of phase partitions (1, 2, 4, 6, 8, 10, 13). The phantom was moved in a cranial-caudal direction with an excursion of 25 mm and a period of 4.0 sec. Five parameters associated to lesion volume and activity concentration were considered to assess the capability of the 4D-PET technique to “freeze” the phantom motion. The results for all the parameters showed the capability of the 4D-PET acquisition technique to “freeze” the lesion motion. The division into six phases was found to be the best compromise between temporal resolution and image noise for the phase where the “lesions” move faster; whereas the partition into four phases could be used if a stable breathing phase is considered.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
