제 7장 X-선의 이용

Tesla obtained the image in 1896 with x-rays generated by his own vacuum tube, similar to Lenard’s tube, at a distance of 8 feet.

Wilhelm Röntgen(1845 ~ 1923)

His first X-ray photo of the bones in his wife’s hand and her wedding ring (1895).First Nobel Prize for physics in 1901.

X-선 발생장치의 개념도

[예제] 5,000V를 사용하여 X-선을 발생시켰을 경우 연속 X-선의

최소파장은 얼마인가?

고유 X-ray의 발생 매커니즘

연속 X-ray의 발생 매커니즘

Target Ka1

(average)Ka1 Ka2 Kb1

Cr 2.29100 2.28970 2.29361 2.08487

Fe 1.93736 1.93604 1.93998 1.75661

Co 1.79026 1.78897 1.79285 1.62079

Cu 1.54184 1.54056 1.54439 1.39222

Mo 0.71073 0.70930 0.71359 0.63229

W 0.021060 0.020899 0.021381 0.018436

회전양극 X-선관

초창기의 X-선 관

여러 종류의 X-선관

양극(표적금속)의 구조

집속장치

파장선택

Target Filter

Incident

beam

I(Ka)/I(Kb)

Filter thickness for

I(Ka)/I(Kb)=500

[mm]

I(Ka)투과/I(Ka)입사

Mo Zr 5.4 0.12 0.29

Cu Ni 7.5 0.02 0.42

Co Fe 9.4 0.018 0.46

Fe Mn 9.0 0.018 0.48

Cr V 8.5 0.015 0.49

Scintillation Counter

Scintillation probe

Geiger counter

X-선 회절실험

Bragg Father and sonNobel prize 1915

Constructive Interference

Destructive Interference

Rosalind Frankin

(1920-1958)

1920 pioneering biochemist Rosalind Franklin, took 1st XRD photos of DNA

The double-helix model of DNA structure was first published in the journal Nature by James Watson and Francis Crick in 1953 based upon the crucial X-ray diffraction image of DNA labeled as “Photo 51”, from Rosalind Franklin in 1952 .

The X-ray diffraction images produced by Maurice Wilkins, Rosalind Franklin, and Raymond Gosling led to the deduction by James Watson and Francis Crick of the 3-dimensional helical nature of DNA.

Maurice Wilkins(1916-2004)물리학자

James Watson (1928- ) Francis Crick(1916-2004)

인체의 각 부분의 X-선 흡수 계수를 결정하여그 차이를 명암으로 처리하여 영상을 얻음

컴퓨터 단층촬영

X-ray Computerized Tomography

(Tomas=slice)

1973: Hounsfield, Cormack 에 의해 개발

The first commercially viable CT scanner was invented by Sir Godfrey Hounsfield in United Kingdom.

160 parallel readings through 180 angles, each 1° apart, with each scan taking a little over 5 minutes.

Allan Cormack of Tufts University independently invented a similar process.

Hounsfield and Cormack shared the 1979 Nobel Prize in medicine.

Allan Cormack Godfrey Hounsfield

흡수계수

단면의 흡수계수 결정

[예제] 어떤 물질로 만든 두께 1mm인 얇은 판에 X-선을 투과시켰을 때

세기가 1/100으로 감소하는 것이 관찰되었다. 이 물질의 흡수계수는 얼

마인가?

CT scanner

X-ray Inspection System

X-ray image

CT scan

공항의 짐검사용 X-선 투시기

인천공항