Design and construction of a thermal neutron beam for BNCT at Tehran Research Reactor.

An irradiation facility has been designed and constructed at Tehran Research Reactor (TRR) for the treatment of shallow tumors using Boron Neutron Capture Therapy (BNCT). TRR has a thermal column which is about 3m in length with a wide square cross section of 1.2×1.2m(2). This facility is filled with removable graphite blocks. The aim of this work is to perform the necessary modifications in the thermal column structure to meet thermal BNCT beam criteria recommended by International Atomic Energy Agency. The main modifications consist of rearranging graphite blocks and reducing the gamma dose rate at the beam exit. Activation foils and TLD700 dosimeter have been used to measure in-air characteristics of the neutron beam. According to the measurements, a thermal flux is 5.6×10(8) (ncm(-2)s(-1)), a cadmium ratio is 186 for gold foils and a gamma dose rate is 0.57Gy h(-1).

A feasibility study of the Tehran research reactor as a neutron source for BNCT.

Investigation on the use of the Tehran Research Reactor (TRR) as a neutron source for Boron Neutron Capture Therapy (BNCT) has been performed by calculating and measuring energy spectrum and the spatial distribution of neutrons in all external irradiation facilities, including six beam tubes, thermal column, and the medical room. Activation methods with multiple foils and a copper wire have been used for the mentioned measurements. The results show that (1) the small diameter and long length beam tubes cannot provide sufficient neutron flux for BNCT; (2) in order to use the medical room, the TRR core should be placed in the open pool position, in this situation the distance between the core and patient position is about 400 cm, so neutron flux cannot be sufficient for BNCT; and (3) the best facility which can be adapted for BNCT application is the thermal column, if all graphite blocks can be removed. The epithermal and fast neutron flux at the beginning of this empty column are 4.12×10(9) and 1.21×10(9) n/cm(2)/s, respectively, which can provide an appropriate neutron beam for BNCT by designing and constructing a proper Beam Shaping Assembly (BSA) structure.

Evaluate of heavy metal concentration in shrimp (Penaeus semisulcatus) and crab (Portunus pelagicus) with INAA method.

The level of the heavy metal in green tiger shrimp (Penaeus semisulcatus) and crab (Portunus pelagicus) caught off the Persian Gulf near Bushehr province were investigated. This study was performed to evaluate instrumental neutron activation analysis (INAA) to analyze heavy metal concentration in crab and shrimp whole body tissue. The order of the swimmer crab and shrimp heavy metal concentrations were Zn>Fe>As>Mn>Co and Fe>Zn>Mn>As>Co, respectively. The results showed swimmer crab (Portunus pelagicus) and shrimp (Penaeus semisulcatus) caught off Persian gulf, were contaminated with high level of As (21.38±3.31ppm and 8.28±2.82 ppm, respectively). High levels of As and Mn were noted in crabs and shrimp, respectively.