Reprint of Application of BNCT to the treatment of HER2+ breast cancer recurrences: Research and developments in Argentina.

In the frame of the Argentine BNCT Project a new research line has been started to study the application of BNCT to the treatment of locoregional recurrences of HER2+ breast cancer subtype. Based on former studies, the strategy considers the use of immunoliposomes as boron carriers nanovehicles to target HER2 overexpressing cells. The essential concerns of the current stage of this proposal are the development of carriers that can improve the efficiency of delivery of boron compounds and the dosimetric assessment of treatment feasibility. For this purpose, an specific pool of clinical cases that can benefit from this application was determined. In this work, we present the proposal and the advances related to the different stages of current research.

Application of BNCT to the treatment of HER2+ breast cancer recurrences: Research and developments in Argentina.

In the frame of the Argentine BNCT Project a new research line has been started to study the application of BNCT to the treatment of locoregional recurrences of HER2+ breast cancer subtype. Based on former studies, the strategy considers the use of immunoliposomes as boron carriers nanovehicles to target HER2 overexpressing cells. The essential concerns of the current stage of this proposal are the development of carriers that can improve the efficiency of delivery of boron compounds and the dosimetric assessment of treatment feasibility. For this purpose, an specific pool of clinical cases that can benefit from this application was determined. In this work, we present the proposal and the advances related to the different stages of current research.

Simulation of the neutron flux in the irradiation facility at RA-3 reactor.

A facility for the irradiation of a section of patients' explanted liver and lung was constructed at RA-3 reactor, Comisión Nacional de Energía Atómica, Argentina. The facility, located in the thermal column, is characterized by the possibility to insert and extract samples without the need to shutdown the reactor. In order to reach the best levels of security and efficacy of the treatment, it is necessary to perform an accurate dosimetry. The possibility to simulate neutron flux and absorbed dose in the explanted organs, together with the experimental dosimetry, allows setting more precise and effective treatment plans. To this end, a computational model of the entire reactor was set-up, and the simulations were validated with the experimental measurements performed in the facility.

New irradiation facility for biomedical applications at the RA-3 reactor thermal column.

A new irradiation facility has been developed in the RA-3 reactor in order to perform trials for the treatment of liver metastases using boron neutron capture therapy (BNCT). RA-3 is a production research reactor that works continuously five days a week. It had a thermal column with a small cross section access tunnel that was not accessible during operation. The objective of the work was to perform the necessary modifications to obtain a facility for irradiating a portion of the human liver. This irradiation facility must be operated without disrupting the normal reactor schedule and requires a highly thermalized neutron spectrum, a thermal flux of around 10(10) n cm(-2)s(-1) that is as isotropic and uniform as possible, as well as on-line instrumentation. The main modifications consist of enlarging the access tunnel inside the thermal column to the suitable dimensions, reducing the gamma dose rate at the irradiation position, and constructing properly shielded entrance gates enabled by logical control to safely irradiate and withdraw samples with the reactor at full power. Activation foils and a neutron shielded graphite ionization chamber were used for a preliminary in-air characterization of the irradiation site. The constructed facility is very practical and easy to use. Operational authorization was obtained from radioprotection personnel after confirming radiation levels did not significantly increase after the modification. A highly thermalized and homogenous irradiation field was obtained. Measurements in the empty cavity showed a thermal flux near 10(10) n cm(-2)s(-1), a cadmium ratio of 4100 for gold foils and a gamma dose rate of approximately 5 Gy h(-1).