Dosimetric Validation of Scans Generated by GAN From Pre-therapeutic MRI in Stereotactic Cerebral Radiotherapy

Study Overview
=================
Brief Summary
-----------------
Stereotactic radiotherapy (SRT) is being widely accepted as a treatment of choice for patients with a small number of brain metastases and an acceptable size, allowing a better target dose conformity resulting in high local control rates and better sparing of organs at risk. Currently, imaging for such a delivery technique requires both a recent magnetic resonance imaging (MRI) brain study for volume definition and a computed tomography (CT) scan for SRT planning. An MRI-only workflow could reduce the risk of misalignment between the two imaging modalities and shorten the delay of planning. Given the absence of a calibrated electronic density on MRI, the investigators aim to assess the equivalence of synthetic CTs generated by a generative adversarial network (GAN) for planning in the brain SRT setting.

Official Title
-----------------
Dosimetric Validation of Scans Generated by GAN From Pre-therapeutic MRI in Stereotactic Cerebral Radiotherapy (SBRT-IRM)

Conditions
-----------------
Brain Metastases

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: age ≥ 18 years old SRT treatment for one or more brain metastasis(ses) brain MRI and planning CT scans realized less than 14 days prior to the treatment delivery Exclusion Criteria: MRI's field of view (FOV) judged insufficient for tumour(s) and OAR visualization

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Local Gamma Analysis Passing Rate | To be considered as comparable, 2 dose maps must have a Local Gamma Analysis Passing Rate higher than 98%. The primary outcome measure will be to compare the Local Gamma Analysis Passing Rate between the 2 dose maps (one initial dosimetric planification and one dosimetric planification extracted from the synthetic ct scan). | Once, at the time of treatment delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Global Gamma Analysis Passing Rate | To be considered as comparable, 2 dose maps must have a Global Gamma Analysis Passing Rate higher than 95%. The primary outcome measure will be to compare the Global Gamma Analysis Passing Rate between the 2 dose maps (one initial dosimetric planification and one dosimetric planification extracted from the synthetic ct scan). | Once, at the time of treatment delivery | 
| Planning Target Volume's coverage values | Planning Target Volume's (PTV) coverage values will be compared between the initial dosimetric planification and the dosimetric planification extracted from the synthetic ct scan. | Once, at the time of treatment delivery | 
| Organs at risk Dose Constraints | Dose constraints to the Organs at Risks (OAR) will be compared between the initial dosimetric planification and the dosimetric planification extracted from the synthetic ct scan. | Once, at the time of treatment delivery |