Hippocampal-Sparing Whole-Brain Radiotherapy: A 'How-To' Technique Using Helical Tomotherapy and Linear Accelerator-Based Intensity-Modulated Radiotherapy

Journal Article · Sun Nov 14 23:00:00 EST 2010 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.01.039· OSTI ID:21438062

Gondi, Vinai ^[1]; Tolakanahalli, Ranjini ^[2]; Mehta, Minesh P ^[1]; Tewatia, Dinesh ^[1]; Rowley, Howard ^[3]; Kuo, John S ^[1]; Khuntia, Deepak ^[1]

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1. Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States)
2. Department of Medical Physics, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States)
3. Department of Neuroradiology, University of Wisconsin Comprehensive Cancer Center, Madison, WI (United States)

Purpose: Sparing the hippocampus during cranial irradiation poses important technical challenges with respect to contouring and treatment planning. Herein we report our preliminary experience with whole-brain radiotherapy using hippocampal sparing for patients with brain metastases. Methods and Materials: Five anonymous patients previously treated with whole-brain radiotherapy with hippocampal sparing were reviewed. The hippocampus was contoured, and hippocampal avoidance regions were created using a 5-mm volumetric expansion around the hippocampus. Helical tomotherapy and linear accelerator (LINAC)-based intensity-modulated radiotherapy (IMRT) treatment plans were generated for a prescription dose of 30 Gy in 10 fractions. Results: On average, the hippocampal avoidance volume was 3.3 cm{sup 3}, occupying 2.1% of the whole-brain planned target volume. Helical tomotherapy spared the hippocampus, with a median dose of 5.5 Gy and maximum dose of 12.8 Gy. LINAC-based IMRT spared the hippocampus, with a median dose of 7.8 Gy and maximum dose of 15.3 Gy. On a per-fraction basis, mean dose to the hippocampus (normalized to 2-Gy fractions) was reduced by 87% to 0.49 Gy{sub 2} using helical tomotherapy and by 81% to 0.73 Gy{sub 2} using LINAC-based IMRT. Target coverage and homogeneity was acceptable with both IMRT modalities, with differences largely attributed to more rapid dose fall-off with helical tomotherapy. Conclusion: Modern IMRT techniques allow for sparing of the hippocampus with acceptable target coverage and homogeneity. Based on compelling preclinical evidence, a Phase II cooperative group trial has been developed to test the postulated neurocognitive benefit.

• OSTI ID: 21438062
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 4 Vol. 78; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ACCELERATORS
AVOIDANCE
BEHAVIOR
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
COMPUTERIZED TOMOGRAPHY
CT-GUIDED RADIOTHERAPY
DIAGNOSTIC TECHNIQUES
DOSES
HIPPOCAMPUS
LINEAR ACCELERATORS
MEDICINE
NERVOUS SYSTEM
NUCLEAR MEDICINE
ORGANS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
THERAPY
TOMOGRAPHY