Calculation and Verification of a Planar Pencil Beam Kernel Through the Hankel Transform of Measured OARs for a Radiosurgery System with Cones

Journal Article · Tue Dec 07 00:00:00 EST 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3531594· OSTI ID:21506969

Vargas Verdesoto, Milton X ^[1]; Alvarez Romero, Jose T ^[2]

---

1. Centro Oncologico de Chihuahua, Hacienda de la Esperanza 6304, Chihuahua, Chihuahua (Mexico)
2. SSDL, Departamento de Metrologia de Radiaciones Ionizantes, Instituto Nacional de Investigaciones Nucleares, La Marquesa, Ocoyoacac, Estado de Mexico 52750 (Mexico)

A planar multienergetic pencil beam kernel with rotational symmetry is calculated for a stereotactic radiosurgery system, SRS, BrainLAB with cones, employing the deconvolution method of the off axis ratio profile, OAR, corresponding to the cone of 35 mm in diameter for a 6 MV photon beam produced by a linear accelerator Varian 2100 C/D. Before the deconvolution, the experimental OAR is corrected for beam divergence and variations of the spectral fluence {Phi}, using a boundary function BF. The function BF and the fluence {Phi} are transformed to the conjugate space with the zero order Hankel function, which is the appropriate transform due to the radial symmetry of the circular beams generated by the cones. The kernel in the conjugate space is obtained as the ratio of the transform of BF to the transform of {Phi}, therefore the kernel in the real space is calculated as the inverse transform of the kernel in the conjugate space. To validate the kernel in the real space, it is convolved with the fluence of the cones of 7.5, 12.5, 15, 17.5, 20, 22.5, 25, 30 and 35 mm in diameter. The comparison of the OARs calculated and measured shows a maximum difference of 4.5% in the zones of high gradient of dose, and a difference less than 2% in the regions of low gradient of dose. Finally, the expanded uncertainty of the kernel is estimated and reported.

• OSTI ID: 21506969
• Journal Information: AIP Conference Proceedings, Vol. 1310, Issue 1; Conference: 11. Mexican symposium on medical physics, Mexico City (Mexico), 19-22 Mar 2010; Other Information: DOI: 10.1063/1.3531594; (c) 2010 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BESSEL FUNCTIONS
COMPARATIVE EVALUATIONS
HANKEL TRANSFORM
KERNELS
LINEAR ACCELERATORS
NEOPLASMS
PHOTON BEAMS
RADIATION DOSES
RADIOTHERAPY
SURGERY
SYMMETRY
VERIFICATION
ACCELERATORS
BEAMS
DISEASES
DOSES
EVALUATION
FUNCTIONS
INTEGRAL TRANSFORMATIONS
MEDICINE
NUCLEAR MEDICINE
RADIOLOGY
THERAPY
TRANSFORMATIONS