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Initial clinical experience with frameless optically guided stereotactic radiosurgery/radiotherapy in pediatric patients.

Keshavarzi S, Meltzer H, Ben-Haim S, Newman CB, Lawson JD, Levy ML, Murphy K - Childs Nerv Syst (2009)

Bottom Line: Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1).We followed patients for a median of 12 months (range 3-18 months) with no in-field failures and were able to obtain encouraging toxicity profiles.Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Division of Neurosurgery, University of California, San Diego, 200 W. Arbor Drive, Suite 8893, San Diego, CA 92103-8893, USA. skeshavarzi@ucsd.edu

ABSTRACT

Objective: The objective of this study is to report our initial experience treating pediatric patients with central nervous system tumors using a frameless, optically guided linear accelerator.

Materials and methods: Pediatric patients were selected for treatment after evaluation by a multidisciplinary neuro-oncology team including neurosurgery, neurology, pathology, oncology, and radiation oncology. Prior to treatment, all patients underwent treatment planning using magnetic resonance imaging (MRI) and treatment simulation on a standard computed tomography scanner (CT). For CT simulation, patients were fitted with a customized plastic face mask with a bite block attached to an optical array with four reflective markers. After ensuring adequate reproducibility, these markers were tracked during treatment by an infra-red camera. All treatments were delivered on a Varian Trilogy linear accelerator. The follow-up period ranges from 1-18 months, with a median follow-up of 6 months.

Results: Nine patients, ages ranging from 12 to 19 years old (median age 15 years old), with a variety of tumors have been treated. Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1). We followed patients for a median of 12 months (range 3-18 months) with no in-field failures and were able to obtain encouraging toxicity profiles.

Conclusion: Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity.

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Related in: MedlinePlus

Patient undergoing a CT (FOV 35 cm, 1.25 mm slice thickness, no contrast) with mask and bite block in place
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Fig1: Patient undergoing a CT (FOV 35 cm, 1.25 mm slice thickness, no contrast) with mask and bite block in place

Mentions: Selected patients underwent a treatment planning MRI with a radiosurgery protocol (fast 3D volumetric T1 scan 512 × 512, 1.5 mm thickness with a 26 cm FOV and no tilt FOV). A customized immobilization device was fabricated for each patient consisting of a headrest, bite block, and mask. The headrest was molded using Accuform (Med-Tec) with the patient’s head placed in the neutral position. To develop the bite block, a dental mold made of dental cement was placed into the bite tray and an impression of the patient’s upper teeth was obtained. After allowing the mold to set, an array of four reflective markers was attached to the bite block, placed in one plane 10–15° from the horizontal. Using the bite block as an attachment to the patient’s teeth, these markers are used as surrogates for patient positioning. Patients are taken to the treatment room where the optical guidance cameras are vaulted to the ceiling. Each patient wears a helmet with a set of test fiducials attached. The patient inserts and removes the bite block (with the markers attached) ten times and each time the relative positioning error is measured. Variation in positioning of <0.75 mm, as measured by the optical guidance camera, was considered acceptable. Once reproducibility has been assessed, patients were taken to the CT simulator. Here, the thermoplastic mask was placed over the patient’s head and molded to their face. With the mask and bite block in place, the patients underwent simulation CT (FOV 35 cm, 1.25 mm slice thickness, with no contrast), with minimization of metal artifact (Fig. 1).Fig. 1


Initial clinical experience with frameless optically guided stereotactic radiosurgery/radiotherapy in pediatric patients.

Keshavarzi S, Meltzer H, Ben-Haim S, Newman CB, Lawson JD, Levy ML, Murphy K - Childs Nerv Syst (2009)

Patient undergoing a CT (FOV 35 cm, 1.25 mm slice thickness, no contrast) with mask and bite block in place
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2691523&req=5

Fig1: Patient undergoing a CT (FOV 35 cm, 1.25 mm slice thickness, no contrast) with mask and bite block in place
Mentions: Selected patients underwent a treatment planning MRI with a radiosurgery protocol (fast 3D volumetric T1 scan 512 × 512, 1.5 mm thickness with a 26 cm FOV and no tilt FOV). A customized immobilization device was fabricated for each patient consisting of a headrest, bite block, and mask. The headrest was molded using Accuform (Med-Tec) with the patient’s head placed in the neutral position. To develop the bite block, a dental mold made of dental cement was placed into the bite tray and an impression of the patient’s upper teeth was obtained. After allowing the mold to set, an array of four reflective markers was attached to the bite block, placed in one plane 10–15° from the horizontal. Using the bite block as an attachment to the patient’s teeth, these markers are used as surrogates for patient positioning. Patients are taken to the treatment room where the optical guidance cameras are vaulted to the ceiling. Each patient wears a helmet with a set of test fiducials attached. The patient inserts and removes the bite block (with the markers attached) ten times and each time the relative positioning error is measured. Variation in positioning of <0.75 mm, as measured by the optical guidance camera, was considered acceptable. Once reproducibility has been assessed, patients were taken to the CT simulator. Here, the thermoplastic mask was placed over the patient’s head and molded to their face. With the mask and bite block in place, the patients underwent simulation CT (FOV 35 cm, 1.25 mm slice thickness, with no contrast), with minimization of metal artifact (Fig. 1).Fig. 1

Bottom Line: Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1).We followed patients for a median of 12 months (range 3-18 months) with no in-field failures and were able to obtain encouraging toxicity profiles.Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Division of Neurosurgery, University of California, San Diego, 200 W. Arbor Drive, Suite 8893, San Diego, CA 92103-8893, USA. skeshavarzi@ucsd.edu

ABSTRACT

Objective: The objective of this study is to report our initial experience treating pediatric patients with central nervous system tumors using a frameless, optically guided linear accelerator.

Materials and methods: Pediatric patients were selected for treatment after evaluation by a multidisciplinary neuro-oncology team including neurosurgery, neurology, pathology, oncology, and radiation oncology. Prior to treatment, all patients underwent treatment planning using magnetic resonance imaging (MRI) and treatment simulation on a standard computed tomography scanner (CT). For CT simulation, patients were fitted with a customized plastic face mask with a bite block attached to an optical array with four reflective markers. After ensuring adequate reproducibility, these markers were tracked during treatment by an infra-red camera. All treatments were delivered on a Varian Trilogy linear accelerator. The follow-up period ranges from 1-18 months, with a median follow-up of 6 months.

Results: Nine patients, ages ranging from 12 to 19 years old (median age 15 years old), with a variety of tumors have been treated. Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1). We followed patients for a median of 12 months (range 3-18 months) with no in-field failures and were able to obtain encouraging toxicity profiles.

Conclusion: Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity.

Show MeSH
Related in: MedlinePlus