正电子发射断层扫描装置（PECT）是（）
A.第一类医疗器械
B.第二类医疗器械
C.第三类医疗器械
D.特殊用途医疗器械
参考答案：C
--- I ____ so busily recently that I ____ no time to help you with your maths.
---That’s OK. I can manage it by myself.
A．had been working; had had
B．have been working; had
C．have been working; have
D．am working; will have
移植肾血流灌注影像浓聚程度大于肾实质摄取像，并且膀胱未见显影，提示()
A．淋巴囊肿
B．急性肾小管坏死
C．尿漏
D．尿路梗阻
E．血栓形成
