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Let's review a case of normal distribution of the

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tracer FDG.

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The highest uptake will always be in the brain

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as it requires large amounts of glucose to function.

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And we can see here that you should expect a difference

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between the gray matter and your white matter.

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Your cortex will be the one taking up the

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glucose in the white matter.

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You only have axons so there's no glucose transporters.

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Moving on salivary glands

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and small lymph nodes, they always have low level

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of FDG uptake.

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The same way that you can see low level

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of FDG uptake in the blood pool.

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We can see in the vessels here

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and we can go to the aortic cards or the heart

0:50

and see that there is low level of FDG uptake here.

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Lungs do not have, uh, tracer uptake

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because the parenchyma is mostly air

1:01

and so that gives us a good basis to identify

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lung lesions in the abdomen.

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The liver would be an organ

1:11

that shows homogeneous moderate degree of three sarepta.

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As you can see here better on the map.

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Liver is commonly used as an organ reference

1:20

to describe things the same way.

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We also use blood pool to compare degree

1:27

of uptake visually.

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The normal uptake of the spleen should be

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mild and should be always equaled or lower than the liver.

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The stomach has diffused low level of uptake,

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but it is also common to see areas

1:47

of more focal uptake.

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And this could be totally physiologic

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or it could be related to gastritis.

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We can also find the same findings on

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the esophagus.

2:00

The kidneys are always showing excretory activity.

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If the patient doesn't have uh, renal insufficiency,

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the highest optic should always be in the collecting system

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in the callis and the pelvis.

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And then, uh, obviously we would see all that concentrated

2:19

excreted tracer in the bladder organs such

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as adrenal glands

2:26

and pancreas can have low level of uptake, again,

2:30

should be diffuse.

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Nothing focal.

2:35

The intestine is an organ that

2:38

also varies in degree of uptake.

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Sometimes you see low uptake like in this case,

2:44

but it can have a higher degree of FDG uptake

2:48

and the specific reasons for

2:50

that are not completely understood

2:52

and they are thought to be multifactorial.

2:55

Being smooth muscle

2:58

That microbiome and peristalsis.

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Many of the reasons that, uh, could give you tracer uptake.

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Bones and bone marrow should have low level

3:13

of uptake in a homogeneous way.

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Like we can see here in the sagittal view.

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The bone marrow has low level of epi G uptake,

3:23

subcutaneous fat, intrabdominal fat.

3:27

They don't have a lot of glucose uptake, so

3:31

you should expect less tracer uptake in those

3:36

areas of the body.