0:00

So part five is now getting a bit technical.

0:03

We're gonna talk about scan parameters and protocols

0:06

and as we said at the very outset of this section,

0:09

we need you to go and have a look at your local protocol.

0:12

'cause it is going to vary from practice

0:14

to practice in terms of, you know,

0:15

the traces we use the camera, you have, you know,

0:18

what local knowledge and expertise has built.

0:21

Um, so I think about you know, the scanner type, the age,

0:23

um, is it time of flight or digital pet scanner

0:26

or is it a total body pet scanner?

0:27

And then also that radiopharmaceutical as we mentioned

0:30

and we met a few of the

0:32

radiopharmaceuticals in the first section.

0:34

But we are going to be mostly focusing on gallium 68 p smma

0:37

11, or gallium PSA, um,

0:40

and then FL in 18 DCF pile

0:43

or A PSR, which are the two most common ones that, um,

0:46

I encounter in practice.

0:48

The difference in terms of these traces is not just,

0:51

you know, subtle differences in, um, image acquisition,

0:53

which you know, with our comparison imaging we saw they're

0:56

pretty similar and certainly comparable

0:58

for progress imaging is thinking about the dose.

1:01

So the dose is different for the two of these.

1:03

Um, but the acquisition time

1:04

is actually pretty much the same.

1:07

So our gallium 68 PSMA protocol, um,

1:10

and we have a digital total body PET ct.

1:13

So our scanning time is actually only five minutes

1:16

for a standard acquisition.

1:17

Um, and we give a dose of 120 megal or 3.25 milli.

1:22

Um, we're in Australia, we use Megal

1:24

for um, our standard patients.

1:26

We inject in the uptake room

1:27

and they get that static scan approximately 50

1:29

to 60 minutes post injection.

1:31

Um, but for patients who have had a prostatectomy,

1:34

which is why flagging this on clinical history is

1:36

so important, we do have the option

1:38

of doing an additional dynamic phase at the beginning.

1:40

And this is an eight to 10 minute dynamic acquisition.

1:43

And what do I mean by that?

1:44

I mean that we are continually acquiring data, um,

1:47

and being a total body pet, we get, um, data for the top

1:50

of the head down to the mid thighs all in one scanning bed

1:53

before we had the total body camera.

1:55

Our dynamics would be just of the pelvis only

1:57

with a 30 centimeter, um, scanning range,

2:00

but same principle looking for early uptake in the region

2:02

of the prostate bed to distinguish it from physiological

2:05

activity, and we'll come back to this in a few sections.

2:07

Time flu in 18 PSR, which we don't tend

2:10

to use routinely in my practice, but local practices do.

2:14

Our protocol is looking at a standard dose

2:15

of approximately 250 megal or 6.75 millicuries.

2:19

And then the acquisition time is the same of five minutes.

2:22

And then with that stand for our uptake period,

2:25

actually we tend to go a little bit against the guidelines

2:28

that we saw a few scans

2:29

before, which is why it's so important

2:30

to check your local practice.

2:31

And we scan it 110 minutes at

2:33

our protocol at Royal North Shore.

2:35

And then, um, for the dynamic,

2:37

the protocol I read was talking about 15 minute dynamic

2:40

acquisition, but that's kind of let

2:42

to be validated on our camera.

2:43

So take that one with a grain of salt.

2:46

So until we spoke, we're also briefly about, um,

2:48

water contrast and dehydration.

2:50

So we try to get our patients to have, um, 900 mls

2:53

to a liter of water in the uptake period.

2:56

And then, you know, so we can break it

2:58

Up. So 25 minutes

2:59

and 40 minutes and just

3:01

before scanning 300 mils each to try

3:03

and flush out the renally excreted radio urine,

3:06

but also kind of to dilute what's there as well.

3:09

Um, and this will help with our scan parameters

3:12

and this is what we get.

3:14

This is our scan, which is acquired.

3:17

Um, this is gallium 68 PSMA acquired at that 50 minutes.

3:22

And then we check it and then hopefully we

3:24

can send the patients home.

3:25

So in that post imaging period, the advice that we give

3:28

to the patients is to avoid close contact.

3:30

Um, and that's kind of less than two meters.

3:32

So, um, radiation is time and distance.

3:35

So avoid prolonged close contact with small children

3:38

and pregnant women for approximately six hours post scan.

3:40

We also kinda encourage them to keep well hydrated as well,

3:43

but otherwise they can essentially go about their day.

3:45

Also in terms of advice, no urine collection, for example,

3:48

for pathology samples for six hours

3:49

because there is still going to be excretion

3:51

of radio urine occurring.