SPECT Gama Kemera Sistemi için Çekim Parametre Değişikliğinin Görüntü Kalitesine Etkisi

Öz

GİRİŞ: Bu çalışmada amacımız gama kamera çekim parametre değişikliklerinin görüntü kalitesi üzerine etkilerini araştırmaktır.

YÖNTEM: Miyokard perfüzyon sintigrafisi ve tiroid sintigrafisi tetkiki için gönderilen toplam 48 hastanın (K:29, E:19, Yaş ortalaması: 47,4±11,1) çift başlı gama kamerada çekimleri yapıldı. Ardından gama kamera çekim parametreleri değiştirilerek (Miyokard perfüzyon sintigrafisi için 64x64 ve 128x128 matrix değişikliği, tiroid sintigrafisi için 5cm ve 10cm uzaklık değişikliği) hastaların yeniden çekimleri yapıldı. Hastaların görüntüleri analiz edildi.

BULGULAR: 64x64 matrikste sol ventrikül ejeksiyon fraksiyonu (EF) değeri: %62,7±8,8 olarak hesaplandı. Aynı hastaların 128x128 matrikste yapılan görüntülemesinde ise EF değeri: %48,9±10,3 olarak düşük bulundu. 10 cm uzaklıktan yapılan ^99mTc-perteknetat uptake sonucu %3,8±2,3 olarak bulundu. Aynı hastaların 5 cm uzaklıktan yapılan uptake sonucu ise %6,2±3,6 olarak yüksek bulundu.

SONUÇ: SPECT gama kamera sisteminde doğru görüntüleme yapabilmek için intrinsic flood-field uniformite ve relative sensitivite değerleri yanında, doğru çekim parametreleri de göz önünde bulundurulmalıdır.

Anahtar Kelimeler

• SPECT gama kamera,99mTeknesyum,kalite kontrol test,çekim parametreleri

Effect of Acquisition Parameters of SPECT Gamma Camera System on Image Quality

Öz

OBJECTIVE: Quality control testing of a SPECT gamma camera is crucial in assessing the suitability of the camera for use in nuclear medicine department. The aim of the present study was to investigate the effect of gamma camera acquisition parameters on image quality.

METHODS: Camera scanning was carried out using a double-headed gamma cameraon a total of 48 patients (29 female and 19 male, mean age: 47.4±11.1) referred to our department for myocardial perfusion scintigraphy and thyroid scintigraphy. Then, camera acquisition parameters were changed (for myocardial perfusion scintigraphy from 64x64 to 128x128 matrix change and for thyroid scintigraphy from 5 cm to 10 cm distance change), and scanning was repeated and images were analyzed.

RESULTS: Left ventricle ejection fraction (EF) value in 64x64 matrix was calculated to be 62.7±8.8%. Smaller EF value of 48.9±10.3% was obtained in 128x128 matrix for the same patients. ^99mTc-pertechnetate uptake percentage was 3.8±2.3% in measurements carried out at a distance of 10 cm. On the other hand, a higher uptake percentage of 6.2±3.6% was found for the same patients measured at a distance of 5 cm.

CONCLUSION: In order to obtain proper imaging in SPECT gamma camera system, correct acquisition parameters should be used along with quality control tests for intrinsic flood-field uniformity and relative sensitivity.

Anahtar Kelimeler

• SPECT gamma camera,99mTechnetium,quality control test,acquisition parameters

Kaynakça

1. Fontana M, Dauvergne D, Letang JM, Ley JL, Testa E. Compton camera study for high efficiency SPECT and benchmark with Anger system. Phys Med Biol 2017;62(23):8794-8812.
2. Jha AK, Mithun S, Chauhan MH, Purandare N, Shah S, Agrawal A, et al. A Novel 141Ce-Based Flood Field Phantom: Assessment of Suitability for Daily Uniformity Testing in a Clinical Nuclear Medicine Department. J Nucl Med Technol 2017;45(3):225-9.
3. Tindale WB. Specifying dual-detector gamma cameras and associated computer systems. Nucl Med Commun 1995;16(7):534-8.
4. Elkamhawy AA, Rothenbach JR, Damaraju S, Badruddin SM. Intrinsic uniformity and relative sensitivity quality control tests for single-head gamma cameras. J Nucl Med Technol 2000;28(4):252-6.
5. O’Connor MK. Instrument- and computer-related problems and artifacts in nuclear medicine. Semin Nucl Med 1996;26(4):256-77.
6. Blokland JA, Camps JA, Pauwels EK. Aspects of performance assessment of whole body imaging systems. Eur J Nucl Med 1997;24(10):1273-83.
7. Kappadath SC, Erwin WD, Wendt RE. Observed inter-camera variability of clinically relevant performance characteristics for Siemens Symbia gamma cameras. J Appl Clin Med Phys 2006;7(4):74-80.
8. Peterson TE, Furenlid LR. SPECT detectors: the Anger Camera and beyond. Phys Med Biol 2011;56(17):145-82.

9. Bolstad R, Brown J, Grantham V. Extrinsic Versus Intrinsic Uniformity Correction for γ-cameras. J Nucl Med Technol 2011;39(3):208-12.
10. Young KC, Kouris K, Awdeh M, Abdel-Dayem HM. Reproducibility and action levels for gamma camera uniformity. Nucl Med Commun 1990;11(2):95-101.
11. Haliloğlu RÇ, Karadeniz Ö, Durak H. A study on the extrinsic sensitivity and counting efficiency of a gamma camera for a cylindrical source and a rectangular detector. Appl Radiat Isot 2017;130:218-23.
12. Zanzonico P. Routine quality control of clinical nuclear medicine instrumentation: a brief review. J Nucl Med 2008;49:1114-31.
13. Rogers WL, Clinthorne NH, Harkness BA, Koral KF, Keyes JW Jr. Field-flood requirements for emission computed tomography with an Anger camera. J Nucl Med 1982;23:162-8.
14. Makarova OV, Yang G, Tang C-M, Mancini DC, Divan R, Yaeger J. Fabrication of collimators for gamma-ray imaging. Proc SPIE 2004;5539:126-32.
15. Wanet PM, Sand A, Abramovici J. Physical and clinical evaluation of high-resolution thyroid pinhole tomography. J Nucl Med 1996;37:2017-2020.
16. Seret A, Defrise M, Blocklet D. 180 degree pinhole SPET with a tilted detector and OS-EM reconstruction: phantom studies and potential clinical applications. Eur J Nucl Med 2001;28:1836-41.
17. Seret A, Bleeser F. Intrinsic uniformity requirements for pinhole SPECT. J Nucl Med Technol 2006;34(1):43-7.