Interventional Radiology

Tumor Ablation

General

  • Comes in 3 Flavors

    • Cryoablation

    • Microwave Ablation (MWA)

    • Radiofrequency ablation (RFA)

Cryoablation

  • Freezes tumor via Joules-Thompson Effect

  • Temperature change of a liquid or gas when it goes from high pressure environment to low pressure environment without heat exchanged with environment

  • Reason why Axe deodorant spray, or WD-40 gets cold when you use a lot at once

  • Goal temp of -80 to -150 deg C

  • Give Argon gas to freeze and kill

    • Then give Helium to thaw and warm back up

  • Multiple freeze and thaw cycles performed

    • 3 for lung

    • 2 for other tissues

  • Look for ice ball formation = oval hypodense area in treatment bed (honestly i dont really see it because like in renal mass tx it already looks part cystic so idk)

  • Advantages

    • Decreased pain vs others

    • Better for renal masses vs others

  • Disadvantages

    • Cost

    • Takes longer vs RF & MWA

    • Need gasses to be available to use

Microwave Ablation

  • Add MWs which agitate water and kills tumor by causing frictional heat

    • Therefore more water content = stronger treatment

    • Goal >60 deg C

    • Faster than RF

    • Less affected by heat sink vs RF

Radiofrequency Ablation

  • Alternating electro-current kills tumor by causing frictional heat

  • Goal heat of 60-100 deg C for 8-15 min

  • Want treated area to be 5-10 mm beyond target border

  • Less risk of bleeding since you’re basically cauterizing everything

  • Associated with more pain vs MWA or cryo

  • Heat Sink effect

    • Basically if blood vessels or bronchi are near target it can take some of the heat from the RF probe making it less effective or needing more time

Avulsion Fractures

  • Avulsion fracture with no (major) trauma of the lesser trochanter - iliopsoas is considered pathologic and indicative of metastatic disease unless proven otherwise

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