Although　targeted　magnetic　hyperthermia　has　been　proven　to　be　an　effective　tumor　abla-tion　technique,　its　use　in　clinical　applications　is　still　scarce　particularly　due　to　the　difficulty　in　imposing　a　desired　nanofluid　distribution　in　the　therapeutic　area.　In　addition　to　the　in-herent　difficulty　of　imposing　a　distribution　with　few　injection　shots,　during　the　nanofluid　infusion,　the　tissue　deformation　can　cause　the　nanofluid　deviation　from　the　targeted　injec-tion　area　and　the　backflow　along　the　needle　can　deliver　the　injected　nanofluid　to　the　outer　surface　of　the　tissue.　Both　phenomena　can　result　in　an　irregular　distribution　for　nanofluid　inside　bio-tissue.　This　study　develops　a　poroelastic　model　considering　geometrically　non-linear　behavior　in　order　to　evaluate　the　effect　of　syringe　needle　size　and　infusion　rate　on　the　backflow.　A　26　gauge　needle　for　syringe　is　used　as　a　typical　example　to　further　in-vestigate　the　nanofluid　transport　and　the　change　of　solid　matrix　material　properties　under　different　infusion　rates　after　comparing　the　infusion　results　for　several　sizes　of　needle.　Fi-nally,　the　resulting　nanofluid　concentration　distribution　obtained　with　the　proposed　model　is　used　to　simulate　the　temperature　distribution　and　the　cancerous　cell　damage.　The　results　demonstrate　that　the　infusion　pressure　and　its　resulting　tissue　deformation　are　the　funda-mental　reasons　for　obtaining　an　irregular　solution　distribution.　Tissue　deformation　induces　the　increase　of　porosity　and　permeability　for　biomaterials　around　the　tip,　and　enhances　the　fluidity　of　nanofluids　inside　the　tissue.　The　results　also　indicate　that　the　increase　in　backflow　length　can　improve　the　uniformity　of　the　nanofluid　distribution　after　diffusion　and,　consequently,　the　treatment　effect.　However,　it　also　increases　the　risk　of　MNP　leakage　from　the　targeted　area　to　the　tumor　surface,　so　it　is　important　to　keep　the　backflow　rate　limited　during　the　injection　process.(c)　2022　Elsevier　Inc.　All　rights　reserved.