Presenting and simulating an innovative model of liver phantom and applying two methods for dosimetry of it in neutron radiation therapy

Abstract

Aim

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.

Materials and 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[[ce:hsp sp="0.25"/]]eV–15[[ce:hsp sp="0.25"/]]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.