AbstractID: 8265 Title: Cerebrospinal irradiation using proton beams for the treatment of medulloblastoma
Cerebrospinal irradiation using proton beams for the
treatment of medulloblastoma
Kambiz Shahnazi∗, Michael Moyers∗, Grace Yuh‡, Daniel Miller∗
Jerry Slater‡, Lilia Loredo‡
Loma Linda University Medical Center, Department of Radiation Medicine, Loma Linda
CA 92354
Abstract:
Purpose: Irradiation of the entire cerebrospinal axis with x-ray beams has been a
standard for medulloblastoma for many years. This treatment has been associated with
side effects such as hypothyroidism, nausea, sore throat, and reduction of blood counts.
This report describes a technique to reduce these side effects by limiting the dose delivery
only to target tissues using proton beams.
Method: The cerebrum was treated with two, opposed, lateral proton beams. The
cribiform plate was treated with a small anterior field patching to the lateral beams. The
spinal axis was treated with posterior fields that matched the lateral cerebral fields.
Results: Several children have been treated using the proton technique. Range of
modulations varied from 30 to 50 mm. Computed dose distributions and dose volume
histograms indicated 40% of the bowel received 20 Gy with x-rays whereas the bowel
remains untouched by the proton beam technique. A dose gradient across the vertebral
bodies indicated a reduction of dose to the growth plates. Patient examinations found
minimal bone marrow suppression.
Conclusion: This work demonstrated the potential of proton therapy for children with
medullobastoma tumors. This technique appears especially advantageous for those
patients who have experienced myelo-suppresion from chemotherapy and may not
otherwise tolerate radiation to a significant portion of their bone marrow supply.