sinogram整理

105-1器材
Ａ 72.發現sinogram有斷點（如圖示），表示造影時：

   

(A)病人左右移動 
(B)病人上下移動 
(C)偵測頭位移 
(D)旋轉中心偏移 



整理：
(A)病人左右移動


(B)病人上下移動 （motion in y-direction）


(C)偵測頭位移 -(b)偵測頭毀損

(b) Sinogram at the middle of the projection showing intense vertical streaks from detector defects.

環狀假影－sinogram出現直線，重建後影像出現同心圓假影


(D)旋轉中心偏移  


Fig.1: Sinogram of Lena (256x256 8-bit image) calculated with a center of rotation (136, 132) roughly corresponding to her right eye. This sinogram was filtered with a ramp filter.

参考文獻

1. Crazybiocomputing.blogspot.com. (2018). Learning Tomography: Non-centered projections. [online] Available at: https://crazybiocomputing.blogspot.com/2013/04/learning-tomography-non-centered.html [Accessed 8 Jun. 2018].
2. Osapublishing.org. (2018). Captcha. [online] Available at: https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-22-16-19078&id=297315 [Accessed 8 Jun. 2018].
3. People.vcu.edu. (2018). SPECT Imaging Characteristics. [online] Available at: http://www.people.vcu.edu/~mhcrosthwait/clrs322/SPECTimagingparameters.html [Accessed 8 Jun. 2018].
4. Slideplayer.com. (2018). Chapter-4 Single-Photon emission computed tomography (SPECT) - ppt video online download. [online] Available at: http://slideplayer.com/slide/10407679/ [Accessed 8 Jun. 2018].

Chang's Method

Chang's Method

1.對於Tc-99m 的光子於軟組織內的μ=0.15cm^-1。
2.射束衰減假設是不均勻
3.Chang's Method：物質與光子產生康普吞散射時，定義約略μ=0.12cm^-1


出處：
１．Slideplayer.com. (2018). Nuclear Medicine Physics - ppt video online download. [online] Available at: http://slideplayer.com/slide/12246744/ [Accessed 4 Jun. 2018].

鑑別時間

鑑別時間=





(103-2物理)
A 34.進行一計算鑑別時間（resolving time）之實驗，已知蓋革計數器所測得A射源、A射源加B射源以及B射源之計數率分別為1182 cps、2063 cps及1223 cps，請計算鑑別時間為若干秒（背景計數率非常小而可以忽略？ 
(A)1.18×10-4 
(B)5.9×10-5 
(C)2.9×10-5 
(D)1.5×10-5 

(1182+1223-2063)/(2x1182x1223)=1.18x10-4