Hydrogen Lithium Helium 1 e 1 p 0

Hydrogen Lithium Helium 1 e 1 p 0 n 2 e 2 p 2 n + + + A = 1, Z=1 3 e 3 p 4 n 1 1 H A = 4, Z=2 No. of neutrons = A Z 4 He 2 A = 7, Z=3 7 3 Li

Atomic Symbol & Isotopes type Mass number Symbol Atomic number isotope (동위원소) isobar (동중원소) isotone (동중성자체) isomer (핵이성체) Z N A = ≠ ≠ = ≠ = = = ≠ = examples 1 H, 2 H 1 90 Sr, 38 90 Y 39 1 59 Co, 27 60 Ni 28 137 m 56 Ba, 137 Ba 56

방사선가중치(계수) (Radiation weighting factor WR)

SI단위 재래식 단위 조사선량 C/kg R 흡수선량 Gy rad 등가선량 Sv 방사능 Bq 관계 1 R = 2. 58 x 10 -4 C/kg 1 Gy = 100 rad rem 1 Sv = 100 rem Ci 1 Ci = 3. 7 x 1010 Bq

Energy conversion when a fast-moving stream of electrons is suddenly decelerated in the anode of x-ray tube

Basic Interactions between X, γ-rays and Matter 1. 2. 3. 4. Photoelectric effect Compton scattering Coherent Scattering Pair Production

Analog & Digital System

Screen-film cassette fluorescent screen #2 Film fluorescent screen #1

Screen-film cassette screen-film 은 빛이 차단된 cassette 속에 “sandwich” 형태로 결합

Radiographic film x-ray absorber radiograph x-ray exposure

영상판 (Image Plate : IP)

F/S System과 CR dynamic range F/S Low Contrast CR High Contrast Film / Screen CR

Hybrid Technology 간접 변환 방식 + 직접 변환 방식 Large Signal

CR과 DR의 비교 P 169 CR DR - IP cassette 촬영 후 Reader에서 Reading - Film scanner, Optic Fiber, Flat Panel Detector, CCD camera 등 - 여러 장치를 하나의 공유 여부 CR로 공유할 수 있다. - 각 장치마다 1: 1로 On -Line 설치해야 함 Detector

p 169 DSA(Digital subtraction angiography(혈관조영 술) Computer process로 Blood vessel(혈관)만을 Real time으로 선명히 묘출

Temporal subtraction

Energy subtraction

CT (Computed Tomography) 컴퓨터 단층 촬영 1972년 4월 영국 EMI사 G. Hounsfield

CT generations

1 st generation CT • Brain 전용 • 기하학적 왜곡 적다. • 직선운동과 원운동 • Pencil beam single detector 로 구성 - Demerit : Long Scan time

1 st generation CT * Single ray pencil beam 　* Head scan only 　* Single detector 　* Linear scan and rotation (1°) 　* Scan time/slice: about 5 min 　* Reconstruction time/slice: 5 min 　* Image size: 80 x 80 　* Voxel size: 3 mm x 13 mm

* Narrow fan beam 　* Linear translational scan and rotation for 2 D scan 　* Whole body scan 　* 30 detector elements 　* Scan time: 10~90 sec

3 rd generation CT • 현재의 CT의 원형 • Rotation & Rotation

* Most widely used in clinical fields 　* Wide fan beam covers whole body 　* Number of detectors: more than several hundreds 　* Scan time: 2~10 sec 　* 360° rotation of source and detectors

Axial Vs. Spiral scan p 178

4 th generation CT • Fixed full detector • High cost

* Fan beam 　* 360° ring of stationary detectors 　* ~2000 detectors 　* Scan time: 0. 5~10 sec 　* Less ring artifact than 3 rd generation 　* Useful for dynamic study

5 th generation CT • Electron beam CT • 1 slice/ 0. 05~0. 1 sec → heart, coronary artery( 관상동맥- 심장을 둘러싼 동맥) • High cost, poor flexibility • Installed worldwide≪ 150

ØCT system T X-ray tube D X-ray detectors X X-ray beam R Gantry rotation

128 -256 MDCT

Virtual colonoscopy : 가상 대장 내시경

Virtual endoscopy : 가상 위 내시경

In vivo In vitro

외웁시다. 꼭 표 5 -7 방사성의약품 p 186 장기 방사성의약품 뇌 133 Xe, 123 I-IMP, 심혈관 99 m. Tc-HAS, 99 m. Tc-RBC 심근 99 m. Tc-chloride 99 m. Tc-HMPAO, 99 m. Tc-ECD 뇌척수액 111 In-DTPA , 99 m. Tc-DTPA 99 m. Tc-sestamibi 갑상선 123 I, 131 I, 99 m. Tc 폐 99 m. Tc-MAA 간 99 m. Tc-sulfurcollid, 뼈 99 m. Tc-MDP 신장 99 m. Tc-DTPA 99 m. Tc-DISIDA 간담도 99 m. Tc-Br. IDA 99 m. Tc-DMSA 종양 201 Tl, 67 Ga 고환 99 m. Tc. O 4