0:00

As with other tracers, there will be pitfalls.

0:03

And also there will be other malignancies that take PSMA,

0:08

even though the name of the tracer is prostate specific.

0:13

It really is a misnomer

0:15

and we'll discuss that later in the course.

0:18

You just have to know that low

0:20

to moderate expression can be observed in any

0:22

of osteoblastic activity as well.

0:24

Not only from metastatic disease, from prostate cancer,

0:28

but from other benign, uh, entities such as osteoarthritis,

0:32

benign lesions such as fibro dysplasia, even fractures if

0:37

you encounter a focal uptake in a single rib

0:42

with a low degree of trace uptake most often than not,

0:47

is going to be a benign lesions such as,

0:51

uh, fibrosis lesion.

0:53

If you have several foci of uptake,

0:56

but they are contiguous, uh, along multiple ribs,

1:00

these might point you towards a trauma.

1:04

These might be fractures.

1:05

So these are things that may help you.

1:08

Budget disease has PSMA uptake as well

1:13

as hemangiomas and other acute

1:15

or chronic inflammatory processes.

1:19

So how to distinguish when things are from

1:23

prostate cancer or, or not.

1:26

I would think that if the uptake is low

1:29

or non-focal, then it is more likely to be unrelated

1:34

to prostate cancer than a metastatic lesion.

1:40

So this is a patient with padgett's disease

1:43

and as you can see there is cortical thickening

1:46

and is bilateral in both iliac bones

1:49

and it's associated with diffuse, mildly patchy,

1:54

but intense PSMA uptake in this case, in spite

1:58

of having intensity that is greater than expected,

2:02

the changes in the bone suggest, uh,

2:04

padgetts disease rather than metastatic origin.

2:09

Also, the uptake is limited to the cortex,

2:12

which is also an additional finding that might help you.

2:17

Malignancies that have PSMA uptake are

2:22

lung, thyroid papillary cancer and follicular rccs

2:27

and oncocytoma and breast cancer.

2:30

However, the mechanism of binding

2:32

of the tracer is different than for prostate cancer

2:36

and it's related to expression

2:38

of PSMA in the vasculature rather than in

2:42

the membrane cell.

2:45

And this is a case of a patient that had a history

2:49

of non-small cell lung cancer that was radiated.

2:52

And uh, you can see here how there is diffuse

2:55

and low PSMA uptake in the area

2:59

Of the treated disease.

3:01

And this had been stable

3:03

and this reflects a uptake from the

3:07

probably chronic inflammation

3:09

of the scar rather than in the lung lesion per se.

3:13

As this was demonstrated with another tracer

3:15

that there was no recurrence

3:18

and this is a separate case, uh, on a patient

3:21

that had a right thyroid lobe hypo nodule

3:25

with focal uptake.

3:28

An ultrasound with FNA was recommended

3:31

and this patient underwent that procedure

3:33

and came back as follicular thyroid cancer.