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In this short video, we're gonna discuss the role

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of F-D-G-P-T-T in solitary pulmonary noles and lung cancer.

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Pett can help predict the likelihood of malignancy

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based upon the degree of tracer uptake,

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but also the morphology.

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With both factors combined,

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we can establish a more accurate interpretation.

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In those cases where we know the patient has a lung cancer,

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we can help stage both

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for novel disease and also for metastatic disease.

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And FDG can provide a more accurate staging

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to avoid unnecessary surgeries

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or to avoid unexpected findings at surgery.

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We can also help in restaging in those patients that have

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received treatment and that show, for instance,

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interval changes on the CT or clinical symptoms.

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So it is important to know what the limitations

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of PET CT are and we have briefly touched on these

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on, on prior videos.

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But the spatial resolution of your system is important.

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This is something you have to be familiar with

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and you can ask your physicist

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or the technologist to provide you with this information.

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Why is this important? Is

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because lesions that are smaller than the spatial resolution

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of your system might be missed on pets

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and you might not get counts from it.

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And so they would potentially look falsely negative.

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Also, respiratory motion plays a role here

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since you have a target that is constantly moving

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because patients don't stop breathing during the pit.

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They have to continue breathing. We call tidal breathing.

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The lung nodules may move up and down

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and that may decrease the amount of

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events that the system can detect.

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Also, it's important to know that FDG,

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even though it's a great tracer, is a sensitive one,

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but it's not a specific.

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And so there are cases in which we have both false positives

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and false negatives.

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And so this is important to always keep in mind

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and think about these.

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Uh, as you review the cases, I'm listing some examples

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of both the scenarios being infection,

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inflammation and sarcoidosis.

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Big common false positive studies in the evaluation of uh,

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lung disease malignancy,

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and then also false negatives that are important

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to know. For instance,

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A tumor that is mucinous won't have

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high FG uptake.

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Those minimally invasive adenocarcinomas

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or low grade malignancies may also show low level

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of tracer uptake depending on the tissue of the density

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of the nodule.

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You can also have low level of FVG uptake

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and it's not necessarily excluding a malignancy.

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And of course cystic lesions

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as the FVG would not be found in the cystic part,

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but only along the walls.

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And then the sub tissue component, if there is any.

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I'm listing here why differential diagnosis

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for solitary pulmonary nodules.

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I'm not go, I'm not gonna go through all of them.

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This can be easily found in many resources,

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but this is important to know that not every

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lung nodule is malignant and

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therefore the differential

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diagnosis will depend upon morphology as well as metabolism.

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How to approach the evaluation

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of a solitary pulmonary nodule on the CT portion

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of the study, I would always look at the presence

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of these elements

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and I would describe the size if I know

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that there has been growth

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and how this growth has been, has it been slow

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or is it rapidly growing?

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How are the margins of this nodule? Where is the nodule?

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Is there calcification or fat? Fat density?

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If there is a broncho gram

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or cavitation, we know that for instance,

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squamous carcinoma has high degree of FDG uptake,

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whereas an insight two

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or a less invasive

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lung tumors can have less degree of FDG uptake.

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Carcinoids are commonly known

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to not have FDG AVID if they are typical.

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And so you also have to acknowledge that

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and if that is your main concern,

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recommend something else like, uh, dotatate to confirm.

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The majority of the tumors that we

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evaluate are going to be adenocarcinomas,

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but uh, there's a variety of lung lesions

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and uh, I am sure that through your

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practice you're gonna encounter them all.

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As far as the mediastinum, it's important to be familiar

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with the different ations.

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Provide an accurate read that is anatomical

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so the surgeon can understand what's the spread of disease.

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Um, you can find this classification easily,

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and I am just showing an example here.

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So now we're gonna go through some cases.