eContour

58 y/o M with metastatic NSCLC and widespread small foci of metastatic intracranial disease referred for consideration of whole brain radiotherapy

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Technique

  • Treated with palliative whole brain radiotherapy with hippocampal avoidance using VMAT

Dose

  • 30 Gy in 10 fractions to the PTV (whole brain minus hippocampal avoidance zone).

Simulation

  • Patient should be simulated supine and immobilized with a three-point frameless mask
  • Fuse the diagnostic MRI brain scan with and without contrast, preferably the thin-cut T1 sequence for delineation of bilateral hippocampi

Contours Per

  1. Bilateral hippocampal contours: Manually generated on the fused thin slice MRI/CT Fusion image set. Delineation should be based on direct anatomic visualization of the hippocampus, typically including the region medial to the temporal horn of the lateral ventricles. Resulting contour is typically bilateral curvilinear structure with overall shape resembling horns. Refer to above atlas and trial.
  2. Hippocampal Avoidance Region: Bilateral hippocampi expanded by 5 mm symmetrically.
  3. PTV: Whole-brain parenchyma, excluding the HA region. No setup margin added to PTV

Plan Evaluation based on NRG CC001

 

PTV_3000

D2%

≤ 37.5 Gy

D98%

≥ 25 Gy

V30Gy

≥ 95 %

Bilateral Hippocampi

D100%

≤ 9 Gy

DMax

≤ 16 Gy

Optic Nerve

DMax

≤ 30 Gy

Optic Chiasm

DMax

≤ 30 Gy

 

Prescribing memantine for patients with high KPS/ECOG scores planned for HA-WBRT (or even WBRT) is considered standard of care. Memantine slows cognitive decline with no difference in OS or PFS (Brown et al., 2013 and Brown et al., 2020)

  • Memantine Prescription:

    Week 1: 5-mg morning dose

    Week 2: 5 mg twice a day week 2

    Week 3: morning dose 10 mg and evening dose 5 mg 

    Weeks 4 through 24: 10 mg twice a day 

  • Extended-release Memantine formulation:

    Week 1: 7-mg daily dose

    Week 2: 14-mg daily 

    Week 3: 21-mg daily dose 

    Weeks 4-24: 28-mg daily dose 

Looking for additional resources? Watch the hippocampus video featuring Dr. Vinai Gondi, as he discusses hippocampal radiology and contouring on the Anatomy & Radiology Contouring (ARC) Bootcamp.