ESTRO 2021 Abstract Book

S1425

ESTRO 2021

Conclusion gNEAT can replace the expensive, time-consuming, and exhaustive trial-and-error process of manual architectural search. Unlike similar automated NAS algorithms, gNEAT can return domain-specific compact solutions in a matter of hours on a low compute system accessible to the majority of research institutions. PO-1698 Changing the paradigm from a « cold » to a radioactive localisation technique in breast surgery C. Dejean 1 , M. Koulibaly 2 , L. Elkind 2 , J. Haudebourg 3 , E. Barranger 4 , C. Hoog 5 1 Centre Antoine-Lacassagne, Medical Physics Unit, Nice, France; 2 Centre Antoine-Lacassagne, Imaging Department, Nice, France; 3 Centre Antoine Lacassagne, Anatomopathological department, NICE, France; 4 Centre Antoine Lacassagne, Department of oncological gynaecological and breast surgery, Nice, France; 5 Centre Antoine Lacassagne, Imaging Department , NICE, France Purpose or Objective To design and implement a randomised multicentre clinical trial concerning feasibility and safety of iodine seed detection compared to standard metal guide detection in patients with invasive / ductal breast carcinoma in situ proven by biopsy in a country where the use of radioactive technique when a non-radioactive one exists must be argued and authorised. Materials and Methods Safety management procedures were implemented and tested on a multidisciplinary basis. Location seeds implanted are retrieved and sent back to the provider, thus French regulation considers them as temporary implants. An in vitro study based on NEMA standards was realised to validate the efficiency of our γ-probes for simultaneous I 125 seed (IsoSeed, Eckert und Ziegler) and Tc 99m sentinel node detection (overlap of Tc 99m scatter on the iodine peak). Patient maximum skin dose exposure was computed using the simplistic TG-43 formalism (infinite and homogeneous water medium, no consideration of density heterogeneities and patient bounds). Whole body, eye lens and extremities dose of involved workers were assessed using quarterly passive dosimeters. Results In vivo study showed the efficiency of the 3 probes and the complete clinical process was safely tested and validated on a roast beef from imaging to detection and surgery. Between 2016 and 2020, 110 patients included in the clinical trial received a 6.9 +/- 1.9 MBq seed implant (maximum 10 MBq) with a mean duration of 3 . 2 +/- 2 . 3 days (maximum 10 days). At respectively 1 & 2 cm depth, the maximum skin absorbed dose computed was 50 & 10 cGy while 11 & 2.5 cGy considering mean activity and duration. These dose rates were not significant to dispense radioprotection recommendations to the patients. Only long cuddle time with children were told to be avoided. Concerning worker radioprotection, seeds were always manipulated with pliers. No individual protection supplies were worn.