ESTRO 2024 - Abstract Book

S215

Brachytherapy - Gynaecology

ESTRO 2024

to reduce training costs. Sustaining and expanding these educational initiatives is necessary for improving cancer care across the continent.

Keywords: Africa, Botswana, Interstitial

331

Proffered Paper

Clinician preferred, fast autoplanning in cervical cancer brachytherapy using BiCycle

Linda Rossi, Rik Bijman, Henrike Westerveld, Miranda Christianen, Lorne Luthart, Michèle Huge, Inger-Karine Kolkman - Deurloo, Jan Willem Mens, Huda Abusaris, Raymond de Boer, Sebastiaan Breedveld, Ben Heijmen, Remi Nout

Erasmus MC, Radiotherapy, Rotterdam, Netherlands

Purpose/Objective:

A new system for fully automated adaptive treatment planning for image-guided cervical cancer brachytherapy following EMBRACE II, named ‘BiCycle’, has recently been developed and retrospectively (internally and externally) dosimetrically validated, showing overall favourable dosimetric quality compared to manual planning [1]. The system has been developed for replacing manual planning in clinical routine, fulfilling EU Medical Device Regulation (MDR) requirements. An important hypothesis was that, apart from increasing plan quality, autoplanning would also significantly reduce daily planning times. In this study, BiCycle was prospectively evaluated with a focus on planning times and subjective plan scoring by treating physician. All five physicians performing cervical cancer brachytherapy in our center participated.

Material/Methods:

Patients were included from June 2022 till January 2023, aiming at 2 evaluable fractions per week, when compatible with clinical workload. Without interfering with current clinical practice, the patient was treated with a manually generated plan: after patient implantation and imaging, a RTT/planner generated a plan in Oncentra (OCB) ( Manual plan generation ), which was optionally adjusted by the treating physician, if desired ( Manual plan adjustment, Man_Adj ) and then delivered. The day after treatment, patient images were used to fully automatically generate a plan using BiCycle ( Auto plan generation ), automatically aiming at equal CTVHR D90% as in the Man_Adj plan. The Auto plan was then imported into OCB, evaluated by the treating physician who worked on the manual plan, and adjusted if desired, resulting in an Auto_Adj plan. Next, the treating physician compared Auto_Adj and Man_Adj plans using Visual Analogue Scales (VAS) for i) overall plan quality, ii) target structures doses only, iii) OARs doses only and iv) loading pattern only. For each VAS, the physician first selected the favourable plan and then expressed the importance of superiority using a 0-100 scale. Both for manual planning and autoplanning, times needed to generate and adjust the plan were recorded.

Results:

The study was approved by the Institutional Review Board. Of the 41 included fractions, 3 were not evaluated in time, and for 1 informed consent was missing, resulting in 37 evaluable fractions. Planning+adjustment time