NaI(TI) SİNTİLASYON VE CdZnTe YARI İLETKEN DEDEKTÖRLÜ GAMA KAMERALARIN PERFORMANS ÖZELLİKLERİNİN KARŞILAŞTIRILMASI

Abstract

Amaç: Son yıllarda yarı iletken dedektörlere (CdZnTe) sahip gama kameralar, nükleer tıpta tanısal sintigrafik görüntülemede rutin uygulamaya girmiştir. Bu çalışmasında, yarı iletken dedektörlü (CdZnTe) bir gama kamera ile NaI(Tl) dedektörlü konvansiyonel bir gama kameranın performans özelliklerinin karşılaştırılması amaçlanmıştır. Gereç ve Yöntemler: Deneysel çalışmalarımızda, farklı aktivitelerde Tc-99m radyoizotopu yerleştirilen aynı uzunluk ve kalınlığa sahip 3 kapiller tüp kullanılarak uzaysal çözünürlük, enerji çözünürlüğü ve doğrusal testler yapılmıştır. Duyarlılık testleri ise 3 cm çapında plastik petri kabına yerleştirilen Tc-99m ile gerçekleştirilmiştir. Kapiler tüplerin ve petri kabının sintigrafik görüntüleri her iki gama kamera ile eşit geometrik koşullar altında alınmıştır. Görüntüler üzerinde ilgi bölgeleri (ROI) çizilmiştir. ROI’deki sayımlara karşılık gelen aktivite miktarı belirlenmiştir. Bulgular: CdZnTe dedektörlü gama kamera ile NaI(Tl) dedektörlü gama kameranın uzaysal çözünürlük, enerji çözünürlüğü ve duyarlılık değerleri sırasıyla; CdZnTe için 7,16 mm, %5,1 ve 17,5 cps/µCi, NaI(Tl) için ise 13,2 mm, %9,4 ve 3,9 cps/µCi olarak bulunmuştur. Sonuç: Çalışmamızın sonuçlarına göre, yarı iletken CdZnTe dedektörlü gama kameranın enerji çözünürlüğü, uzaysal çözünürlüğü, duyarlılığı ve doğrusal özelliklerinin NaI(Tl) dedektörlü gama kameraya göre üstün olduğu sonucuna varılmıştır.

Keywords

• Gama kamera
• yarı iletken dedektör
• CdZnTe
• enerji çözünürlüğü
• uzaysal çözünürlük

COMPARISON OF PERFORMANCE CHARACTERISTICS OF GAMMA CAMERAS WITH SCINTILLATION NaI(TI) AND SEMICONDUCTOR CdZnTe DETECTORS

Abstract

Objective: In recent years, gamma cameras with semiconductor detectors (CdZnTe) have entered routine practise diagnostic scintigraphic imaging in nuclear medicine. In this study, we aimed to compare the performance characteristics of a gamma camera with a semiconductor detector (CdZnTe) and a conventional gamma camera with a NaI(Tl) detector. Material and Methods: In our experimental studies, spatial resolution, energy resolution, and linearity tests were performed using 3 capillary tubes of the same length and thickness, into which the Tc-99m radioisotope with different activities was placed. Sensitivity tests were performed by placing Tc-99m in a plastic Petri dish with a diameter of 3 cm. Scintigraphic images of the capillary tubes and the Petri dish were taken with both gamma cameras under equal geometric conditions. Regions of interest (ROI) were drawn on the images. The activity amount corresponding to the counts in the ROI was determined. Results: The spatial resolution, energy resolution, and sensitivity values of the gamma camera with the CdZnTe detector and the gamma camera with NaI(Tl) detector are respectively: 7.16 mm, 5.1% and 17.5 cps/µCi for CdZnTe, and 13.2 mm, 9.4% and 3.9 cps/µCi for NaI(Tl) µCi respectively. Conclusion: According to the results of our study, it was concluded that the energy resolution, spatial resolution, sensitivity, and linearity properties of the gamma camera with the semiconductor CdZnTe detector are superior to those of the gamma camera with the NaI(Tl) detector.

Keywords

• Gamma camera
• semiconductor detector
• CdZnTe
• energy resolution
• spatial resolution

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