Abstract Body: CartiGeneaTM by Biopharmaceuticals Ltd is an advanced therapy medicinal autologous service for use in ACI treatment. CartiGeneaTM is an autologous suspension of approximately 15,000 ex vivo expanded cartilage cells per microliter of combined medium for autologous use. The cells have been obtained by ex vivo expansion of chondrocytes isolated from a biopsy of the articular cartilage from the patient’s knee. Treatment with CartiGeneaTM comprises a two-step surgical procedure. In the first step a cartilage biopsy is obtained arthroscopically from healthy articular cartilage from a lesser weight bearing area of the patient’s knee, approximately 4 weeks prior to implantation. Chondrocytes are isolated from the biopsy by enzymatic digestion, expanded in vitro, characterised and delivered as a suspension of 1 x 104 cells/μl for implantation in the same patient. During the second step of the procedure the expanded chondrocyte suspension is implanted in an open-knee surgery. The dosage of the cell suspension is defined as 0.8 to 1.5 million cells per cm2 defect size. Hence, depending on the defect size measured at biopsy procurement, 4 or 8 or 12 million cells are formulated into 1 or 2 or 3 vial(s) of 4 million cells/ 0.4 ml excipient. The claimed indication for CartiGeneaTM is repair of single symptomatic cartilaginous defects of the femoral condyle of the knee (ICRS grade III or IV) in adults. By use of the proposed phantom method, dose reduction up to 75% was achievable, whereas for an intermediate level of iteration (level 4), the dose reduction ranged between 50% and 60%, depending on the tube voltage. For comparison, with the gradual adjustment of exposure settings, the corresponding dose reduction for the same level of iteration was about 35%. The proposed method provides rapid and efficient optimization of CT protocols and could be used as the first step in the optimization proces