Presenting and simulating an innovative model of liver phantom and applying two methods for dosimetry of it in neutron radiation therapy.
OBJECTIVE
A new model of liver phantom is defined, then this model is simulated by MCNPX code for dosimetry in neutron radiation therapy. Additionally, an analytical method is applied based on neutrons collisions and mathematical equations to estimate absorbed doses. Finally, the results obtained from two methods are compared to each other to justify the approach.


BACKGROUND
The course of treatment by neutron radiation can be implemented to treat cancerous tissues, although this method has not yet been widespread. The MIRD and the Stylized Family Phantom were the first anthropomorphic phantoms, although the representation of internal organs was quite crude in them. At present, a water phantom is usually used for clinical dosimetry.


METHODS
Each of the materials in an adult liver tissue including water and some organic compounds is decomposed into its constituent elements based on mass percentage and density of every element. Then, the accurate mass of every decomposed material of human liver tissue is correlated to masses of the phantom components.


RESULTS
The absorbed doses are computed by MCNPX simulation and analytical method in all components and different layers of this phantom.


CONCLUSIONS
Within neutron energy range of 0.001 eV-15 MeV, the calculated doses by MCNPX code are approximately similar to results obtained by analytical method, and the derived graphs of both methods approve one another. It is also concluded that through increasing the incident neutron energy, water receives the largest amounts of absorbed doses, and carbon, nitrogen and sulfur receive correspondingly less amounts, respectively.
Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Seyed Alireza
SA
Mousavi Shirazi
Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Ali
A
Pazirandeh
Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Gholamreza
G
Jahanfarnia
Department of Nuclear Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Mitra
M
Athari Allaf
Analytical approximation; Dose; Liver phantom; MCNPX code; Neutron; Radiation