kul introduction radiology

8/3/2019 Kul Introduction Radiology

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INTRODUCTION

RADIOLOGY

DEPARTEMENT OF RADIOLOGY

FACULTY OF MEDICINE, UNIV.OF NORTH SUMATERA

MEDAN.


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What is Radiology?

The use of X-rays and radioactivesubstances in the diagnosis and treatment

of disease.


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What is Radiology?

Radiology is the study of images

of the human - body.

Although Radiology began withthe use of X-Rays and

photographic films, the modernRadiologist now has a

variety of tools for "takingpictures" of patients.

Many of these newer tools createan image with a compu-

ter (CTcomputed tomography)and some do not use any

X-Rays, such as MR andUltrasound.


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Discovery of X-RAYS

Wilhelm Conrad Rontgen,Professor of Physics at Universityof Wurzgburg, first made thediscovery of

X ray on 8th November,1895.


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Discovery of X-RAYS

Rontgen discovered that these rays couldpass through all sort of objects

Moreover he could see the shadow ofbones and soft tissues of his own

hand on the fluorescent screen, when hishand was placed between the

glass tube and the screen.

To document these rays, he replaced thefluorescent screen with

photographic plate, to make a

photographic record.

The photograph of his wife hand, waswidely

believed to be first ever radiograph (X-raypicture)

of a human.


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X RAY PRODUCTION

When electrons traveling at very high speeds are madeto penetrate the atom target, transfer of energy fromelectron to the atom target causes internalderangement and release of X rays.


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X-RAYS

1. A Form of radiant

electromagnetic energy.

2. Invisible to human eye. 3. Passes through all of

objects .

4. Causes fluorescence. 5. Exposes film etc..


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FORMATION OF THE X RAYIMAGE

The formation of a X ray image depends on ;

1. Intensity (strength) of the X ray beam

2. Physical properties of the structure through

which it passes.

thickness, density and atomic number of structures.


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FORMATION OF THE X RAY

IMAGEIf two adjacent structures

are of similar densityand

X-rays passing difficultyindistinguishing thesetwo

structures.

Structures with greatlydiffering densities andatomic

number are seen clearly.


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Diagnostic Radiology

The discovery of X rays was

not only an important

scientific event (Nobel Prize),

but more significantly

heralded a new era in

medical practice.

The concept of diagnosticimaging:

To visualize internal body

structures and organs and

hence detect diseases.


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RADIOLOGIC TECHNIQUES

Plain Radiographs

Fluoroscopy

Contrast Radiography Angiography

Computed Tomography

Magnetic ResonanceImaging

Nuclear Medicine

Ultra Sound


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PLAIN RADIOGRAPHS

The images created by X-rays.Often called "plain X-rays"

The image or picture is basicallya shadow of the parts of thepatient that absorb or block theX-rays.

The image can be collected onphotosensitive film, on a digitalimaging plate, or on a

fluoroscopic screen.


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DIAGNOSTIC RADIOLOGY In the early years, the main

indication for the X rayexaminations were todiagnose fractures and

dislocation, locate foreignbodies, to visualizecongenital deformities, andto examines specific diseases

affecting bone.These clinical indicationsstill remain valid in todaypractice.


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What is a Radiologist ?

Use of imaging techniques,such as X ray, US or CT Scan,in the diagnosis and

treatment of disease Role of Radiologist:

1. Identify abnormality (Nl orAbnl)

2. Characterize abnormality

3. Extent of disease (Staging)

4. Differential diagnosis

5. Suggest further work up


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Tabung Sinar-X

Tabung luar

Tabung (gelas) sinar-x berada didalamtabung luar(pembungkus)

Tabung (gelas) sinar-x

Dua diodaKatoda

Anoda


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Katoda

Elektoda bermuatan listrik

negatif

Filamen katoda sumber

elektron untuk produksisinar-x

Emisi termal (panas)

terjadi ketika filamen

dialiri listrik elektronlepas awan space

charge


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Anoda

Elektoda bermuatan

listrik positif

Tipe

Rotasi Radiologi

diagnostik

Permanen

Menerima elektron difokuskan (focal spot)

sinar-x terfokus

diproyeksi ke target

tubuh


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Sinar-X

Hasil benturan

elektron dengan

katoda Produksi radiograf

(gambar)

Kilovoltase

Miliamper

Waktu

Ukuran focal spot


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Miliampere

Mengontrol jumlah aliran

listrik ke filamen katoda

Miliampere second (mAs)

Jumlah total aliran listrik

yang melintas di dalamtabung sinar-x selama

pemaparan (exposure)


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Kilovoltase

Jumlah tegangan

listrik yang

melintas di dalamtabung sinar-x

selama pemaparan


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Faktor Exposure

Kilovoltase

Miliampere

Waktu exposure

Table top atauPotter-Bucky

Anatomi tubuh


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Film

Base/dasar Bahan tipis transparan

Mempertahankan bentuk

Mencegah terlipat

Alas/penahan emulsi

Emulsi

Melapisi base di kedua sisi


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Emulsi Film

Lapisan sensitif

terhadap cahaya dan

sinar-x

Kristal Silver

halide granular

halus sensitivity

specks


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Tipe Film

Blue sensitive

Sensitif terhadap cahaya

biru-violet

Panchromatic fotografi

Orthochromatic radiologi Green sensitive

Seluruh warna kecuali

merah


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Kaset

Tempat film

Pengaman film dari

cahaya Intensifying

screen

Screen baseLapisan reflektor

Lapisan fosfor

Lapisan proteksi


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Proses Radiograf

Gambar laten diproduksi

oleh perubahan yang tidak

terlihat ketika emulsi

terpapar oleh sinar-x ataucahaya

Jumlah deposit metalic

silver dalam emulsi

tergantung jumlah kristalhalida yang terpapar

Metalic silver menghasilkan

penghitaman film


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Proses Radiograf

K

amar gelap harus terisolir dari radiasi Proses terjadinya gambar

Development (pengembangan)

Fixing (pemampatan)

Washing (pembersihan) Drying (pengeringan)


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Proses Radiograf

Developer bekerja pada

emulsi sehingga imej

menjadi terlihat

Fixer

Menetralisir developer

Mengeraskan emulsi


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Exposure


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Developing penghitaman


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Developing akselerasi


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Developing restrainer


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Developing preservative


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Fixing


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Otomatis


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Densitas

Dikontrol mAs

mAs meningkat pemaparan meningkat


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200 400 mAs


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Kilovoltase

Kilovoltase

meningkat foton

sinar-x meningkat energi meningkat

Kilovotase meningkat penetrasi sinar-x

meningkat


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kV


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kV naik


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45 88 kV (ada densitas)


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Jarak

FFD (focus film distance)

Jarak dari fokus ke film

Dua kali FFD area

terpapar meningkat 4 kali intensitas berkurang kali dari

semula


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Kwalitas

Gambar tajam dengan

densitas dan kontras

yang adekuat

Densitas radiografik

penghitaman film

Densitas dikontrol oleh

mAs


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Kontras

Detail gambar terlihat

Variasi tingkat densitas

sehingga detail gambar terlihat

Dikontrol oleh kilovoltase

Hasil pelemahan dan perbedaanabsorbsi di jaringan

Pelemahan dan penetrasi pada

tubuh di kontrol oleh kilovoltase


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Kontras


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Densitas


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Definisi :

Kejelasan dan ketajaman

garis dari struktur anatomi

tubuh

Distorsi :

Misinterpretasi ukuran dan

bentuk anatomi yang dinilai


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Definisi


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Distorsi


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Radiographic Quality

Control Influence

DensityContrast

Definition

Distortion

mAskV

FFD

FFD

Kv & FFD

kV & mAs

T


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