Sains Malaysiana 48(1)(2019): 191–197

http://dx.doi.org/10.17576/jsm-2019-4801-22

 

Measurement of Neutron Flux and Gamma Dose Rate Distribution Inside a Water Phantom for Boron Neutron Capture Therapy Study at Dalat Research Reactor

(Pengukuran Neutron Fluks dan Pengagihan Kadar Dos Gama dalam Fantom Air untuk Kajian Terapi Boron Neutron Tertawan di Reaktor Penyelidikan Dalat)

 

TRINH THI TU ANH1*, PHAM DANG QUYET1, MAI NGUYEN TRONG NHAN2 & PHAM NGOC SON3

 

1Dalat University, 01 Phu Dong Thien Vuong, Dalat, Vietnam

 

2Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea

 

3Nuclear Research Institute, 01 Phu Dong Thien Vuong, Dalat, Vietnam

 

Diserahkan: 7 Jun 2018/Diterima: 7 September 2018

 

ABSTRACT

Exposure dose rate to the tumor and surrounding cells during neutron beam irradiation in Boron Neutron Capture Therapy (BNCT) comes not only from heavy charged particles produced from the 10B(n,α)7Li nuclear reaction, but also from neutron-induced reactions with other biological elements in living tissue, as well as from gamma rays leaked from the reactor core. At Dalat Research Reactor, Vietnam, the neutron and gamma dose rate distribution inside a water phantom were measured by using activation method and Thermoluminescent Dosimeter (TLD) detector, respectively. The results showed that effective thermal neutron dose rate along the center line of the water phantom had a maximum value of 479 mSv h-1 at 1 cm in phantom and then decreases rapidly to 4.87 mSv h-1 at 10 cm. The gamma dose rate along the center line of the water phantom also reach its maximum of 4.31 mSv h-1 at 1 cm depth and decreases to 1.16 mSv h-1 at 10 cm position. The maximum biological tumor dose rate was 1.74 Gy-eq h-1, not high enough to satisfy the treatment requirement of brain tumors. However, the results of this work are important in supporting of BNCT study in the upcoming stages at Dalat Research Reactor.

 

Keywords: BNCT; dose rate; TLD detector; thermal neutron flux; water phantom

 

ABSTRAK

Kadar dos pendedahan kepada tumor dan sel sekitarnya semasa pancaran sinaran neutron dalam Terapi Boron Neutron Tertawan (BNCT) datang bukan sahaja daripada zarah berat bercas yang dihasilkan daripada tindak balas nuklear 10B(n,α)7Li, tetapi juga daripada tindak balas neutron-teraruh daripada unsur biologi lain dalam tisu hidup, selain daripada sinar gama yang bocor daripada teras reaktor. Di Reaktor Penyelidikan Dalat, Vietnam, kadar pengagihan dos neutron dan gama dalam fantom air diukur masing-masing menggunakan kaedah pengaktifan dan pengesan Thermoluminescent Dosimeter (TLD). Keputusan menunjukkan bahawa kadar dos haba neutron yang berkesan sepanjang garis tengah fantom air mempunyai nilai maksimum 479 mSv h-1 pada 1 cm dalam phantom dan kemudian menurun dengan pantas kepada 4.87 mSv h-1 pada 10 cm. Kadar dos gama sepanjang garis tengah fantom air juga mencapai tahap maksimum 4.31 mSv h-1 pada kedalaman 1 cm dan menurun ke 1.16 mSv h-1 pada kedudukan 10 cm. Kadar dos maksimum tumor biologi adalah 1.74 Gy-eq h-1 namun tidak cukup tinggi untuk memenuhi keperluan rawatan tumor otak. Walau bagaimanapun, keputusan kajian ini adalah penting dalam menyokong pengajian BNCT pada peringkat akan datang di Reaktor Penyelidikan Dalat.

 

Kata kunci: BNCT; fantom air; fluks haba neutron; kadar dos; pengesan TLD

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*Pengarang untuk surat-menyurat; email: anhttt@dlu.edu.vn

 

 

 

 

 

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