Κατεύθυνση Ιατρική Φυσική-Ακτινοφυσική
Library of the School of Health Sciences

2018-05-14

2018

Katsiva Christina

Αναστάσιος Σιούντας, Αναπληρωτής Καθηγητής, Ιατρική, ΑΠΘ
Αργύριος Δούμας, Αναπληρωτής Καθηγητής, Ιατρική, ΑΠΘ
Εμμανουήλ Παπαναστασίου, Επίκουρος Καθηγητής, Ιατρική, ΑΠΘ

Ανάλυση ημιποσοτικών μετρήσεων σε τομογραφικές μελέτες εγκεφάλου με Ι-123: μελέτη σε ομοίωμα

Greek

Analysis of semiquantitative measurements on tomographic brain studies with I-123: a phantom study

DaTSCAN or 123I-FP-CIT imaging is indicated for detecting loss of functional dopaminergic neuron terminals in the striatum of patients with clinically uncertain parkinsonian syndromes. Visual assessment allows the normality of DAT binding to be evaluated, and, if it is abnormal, to evaluate the magnitude of compromised DAT binding. Except from the visual assessment, values from semiquantitative analysis are used. These values are the Specific Binding Ratio – SBR.
The purpose of this study was the assessment of the variation of the SBR, when the following factors changed: Region Of Interest (ROI), Algorithm and its parameters, Scatter Correction or No Scatter Correction, Collimator, Radius of rotation. The radius of rotation is especially important because in clinical practice it is highly possible that the recommended values cannot be applied, due to the body type of the patient or due to the feeling of claustrophobia.
For the experimental part of this study two simple brain phantoms were reconstructed. The first one was a simulation of a normal patient and the second one a simulation of a pathological patient. The γ-camera of use was the dual head General Electric Discovery NM 630, four different radius of rotation were applied (12, 16, 20 and 24 cm) and two different collimators were used (LEHR και MEGP). There were images without scatter correction, with Dual Energy Window (DEW) and with Triple Energy Window scatter correction (TEW). The algorithms that were applied were the FBP and OSEM. The Chang attenuation correction method was applied to every reconstruction.
It was observed that values from the semiquantitative analysis were strongly dependent on the data acquisition procedure and the corrections performed. When scatter correction was applied the SBR value increased from 10% to 70%, depending on the radius of rotation and the collimator of use. Moreover when scatter correction was applied the recovery of the true value was higher and the highest percentage that was achieved was 60%. Due to the importance of radius dependence on the SBR values, correction factors were calculated. It is advised that correction factors are to be used when the radius of rotation is greater than the recommended values.

Health Sciences

Semiquantitative measurements, Brain, I-123, Phantom

No

0

Yes

17

124

File access is restricted only to the intranet of UoA.

https://pergamos.lib.uoa.gr/uoa/dl/object/2758649