['To compare the impact of single fractional with bi-fractional irradiation on the depth of doxorubicin penetration into the normal tissue after pressurized intra-peritoneal aerosol chemotherapy (PIPAC) in our ex vivo model.', 'Fresh post mortem swine peritoneum was cut into 12 proportional sections. Two control samples were treated with PIPAC only (no irradiation), one sample on day 1, the other on day 2. Five samples were irradiated with 1, 2, 4, 7 or 14 Gy followed by PIPAC. Four samples were treated on day one with 0.5, 1, 2, 3.5 or 7 Gy and with the same radiation dose 24 h later followed by PIPAC. Doxorubicin was aerosolized in an ex vivo PIPAC model at 12 mmHg/36°C. In-tissue doxorubicin penetration was measured using fluorescence microscopy on frozen thin sections.', 'Doxorubicin penetration (DP) after PIPAC for the control samples was 407 μm and 373 μm, respectively. DP for samples with single fraction irradiation was 396 μm after 1 Gy, 384 μm after 2 Gy, 327 μm after 4 Gy, 280 μm after 7 Gy and 243 μm after 14 Gy. DP for samples with 2 fractions of irradiation was 376 μm after 0.5+0.5 Gy, 363 μm after 1+1 Gy, 372 μm after 2+2 Gy, 341 μm after 3.5+3.5 and 301 μm after 7+7 Gy irradiation. Fractionating of the irradiation did not significantly change DP into normal tissue.'] Does irradiation Increase the Penetration Depth of Doxorubicin in Normal Tissue After Pressurized Intra-peritoneal Aerosol Chemotherapy ( PIPAC ) in an Ex Vivo Model?