Target Volume Determination 2015

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StefanDelorme Division ofRadiology

Slice selection

k-space

T2-weighted images

21.05.14 |

Bright:

Brain

• Concept • z gradient and HF puls simultaneous • Only spins in one slice will be excited

Long T2:

Fat (moderately) Blood Fluid Many pathologies

Tumor

Fourier

CSF

Edema

Dark:

Short T2:

Trans- formation

After Gd-DTPA (slightly) Bone, calcium Blood (Hämosiderine)

B (z)

Flow: Signal void Lack of protons: Air

Vessels

Bone

Image

k-space

StefanDelorme Division ofRadiology

Contrast medium: Gd-DTPA

T1-weighting

Outline

21.05.14 |

Bright :

• GD3+ is paramagnetic • Reduces relaxation times in tissue • Affects mainly T1 • Toxic if liberated, inert as a DTPA chelate • Other chelates: DOTA, DTPA-BMA, etc. • Excreted in urine • Administration i.v., oral possible

• Computed tomography • How it works • Strengths • Weaknesses • Magnetic resonance imaging • How it works • Strengths • Weaknesses • Ultrasound • How it works • Strengths • Weaknesses

Fat

Short T1: Fat

Gd-DTPA

Blood (age !) After Gd-DTPA: disturbed BBB Fluid with high protein content

CSF

Tumor

Dark :

Long T1:

Free water Bone, calcium

Flow: signal void Lack of protons: air

Bone

Brain

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