Inclusion Criteria:

1. Pediatric patients with diffuse intrinsic brainstem gliomas, documented by standard
imaging techniques (MRI). Note: Tumor biopsy and histological confirmation are not
required in this study.

2. Patients eligible for radiotherapy with Cobalt60. The patients should not have
received a previous specific oncological treatment.

3. Aged > 3 years old < 18 years old

4. Patients with measurable lesions, defined as those that can be accurately measured in
at least 2 dimensions (the 2 largest perpendicular diameters), using standard
techniques (MRI).

5. Female patients with childbearing potential should present a negative pregnancy test
and adopt effective birth control methods, in case they are sexually active.

6. Male patients who can father a child should adopt effective birth control methods, in
case they are sexually active.

7. Life expectancy > 12 weeks

8. Health general status, according to Karnofsky Index > 40% (Karnofsky Index for
patients > 16 years old), Lansky > 40% (for patients < 16 years old)

9. Laboratory parameters within the normal limits, defined as: Hematopoietic: Hemoglobin
> 10 g/L, Total Leukocytes > 2 x 109 cells/L, Platelets > 100 x 109/L; Hepatic: Liver
functioning within the normal limits and without hepatic diseases demonstrated by
ALT, AST < 2.5 x above the reference value and Total Bilirubin < 1.5 x above the
reference value; Renal function: Serum Creatinine < 1.5 x above the reference value.

10. The parents or legal guardians should express, voluntarily, in writing, that the
patient will be enrolled in the study upon signature of the informed consent form. At
the investigator's discretion, where applicable, the consent will be obtained from
the minor.

Exclusion Criteria:

1. Low-grade brainstem glioma (e.g., focal, cervicomedullary, tectal brainstem glioma).

2. Patients previously treated with some AcM.

3. Patients previously treated with some antineoplastic therapy, including chemotherapy,
immunotherapy or radiotherapy.

4. Concurrent treatment with some antineoplastic therapy not conceived in the study
protocol.

5. Breastfeeding or pregnant patients.

6. Patients that, at the time of enrollment, have some related chronic disease under
decompensation (e.g., cardiopathy, diabetes, hypertension).

7. Patients who have history of hypersensitivity to this or another similar product.

8. Fever, severe septic processes and/or severe or acute allergy.

9. Patients who are participating in another clinical study with therapeutic purposes
for their disease based on the time of the study enrollment.

10. Presence of a second tumor.