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Sains Malaysiana 46(2)(2017): 303–308 http://dx.doi.org/10.17576/jsm-2017-4602-15 6 MV Photon Beam Induced UV/VIS
Absorption of Hema Polymer Gel (Alur Foton 6 MV Teraruh Penyerapan UV/VIS Gel Polimer HEMA) SITI ATIQAH
ISHAK*,
ISKANDAR SHAHRIM, SITI,
K.A.R.
& AZHAR A. ALRAHMAN School
of Physics, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia Diserahkan:
22 Ogos 2014/Diterima: 24 Mei 2016 ABSTRACT The aim of this study was to
evaluate properties of normoxic polymer gel 2-Hydroxyethyl methacrylate
monomer (HEMAG)
as a point dosimeter by using optical properties evaluation techniques.
HEMAG
were prepared from seven different radiation dose
within five different depths of HEMAG dosimeters. These HEMAG
dosimeters were irradiated by linear accelerator
with 6 MV
photon beams. The absorption spectra were measured
by using a UV-visible
spectrophotometer in the wavelength range from 300 to 800 nm.
Then, the data was analysed to determine the optical energy band
gap (Eg) and
Urbach’s energy (ΔE). The result showed that Eg and
ΔE were dependent on radiation dose and percentage
of depth dose (PDD).
In additional, Eg with indirect transition of HEMAG
decreased as radiation dose increased and increased
with traversing of depth. ΔE of HEMAG increased as the dose increased
and decreased with traversing depth of monomer. There was a shift
in the Eg values towards lower energy as the dose increased and
led to a shift of the ΔE value towards the higher
energy with increasing dose. This observation supported the increase
of structured disorder of the polymer with increasing radiation
dose, which resulted in the lower energy transitions that was
feasible and reduced the values of Eg.
In conclusion, HEMAG has a potential to be used as a
dosimeter at low radiation dose in the clinical radiotherapy. Keywords: HEMAG;
optical properties; optical band gap; polymer gel; Urbach energy;
UV-vis
spectrophotometer ABSTRAK Tujuan kajian ini ialah untuk
menilai sifat poli-hidroksimetilakrilit gel (HEMAG)
sebagai dosimeter titik dengan menggunakan teknik penilaian sifat
optik. HEMAG
disediakan daripada tujuh dos sinaran berbeza dilingkungi
lima kedalaman dosimeter HEMAG yang berbeza. Dosimeter HEMAG
dipersinarkan menggunakan pemecut linear dengan
alur foton 6 MV.
Spektra serapan diukur dengan menggunakan spektrofotometer UV-nampak
pada julat panjang gelombang dari 300 hingga 800 nm. Kemudian,
data dianalisis untuk menentukan jurang jalur tenaga optik (Eg)
dan tenaga Urbach (ΔE). Keputusan menunjukkan Eg dan
ΔE bergantung kepada dos sinaran dan peratus kedalaman
dos (PDD).
Sebagai tambahan, Eg dengan transisi tak langsung HEMAG
berkurang apabila dos sinaran meningkat dan meningkat
dengan penyusuran kedalaman. ΔE HEMAG meningkat apabila dos meingkat
dan menurun dengan penyusuran kedalaman monomer. Terdapat anjakan
di dalam nilai Eg terhadap tenaga rendah apabila dos
meningkat dan menjurus ke anjakan nilai ΔE terhadap tenaga
tinggi dengan penigkatan dos. Pemerhatian ini menyokong peningkatan
ketaktertiban berstruktur polimer dengan peningkatan dos, yang
dihasilkan di dalam tenaga transisi rendah yang tersaur dan mengurangkan
nilai-nilai Eg. Secara kesimpulan, HEMAG mempunyai potensi untuk digunakan sebagai dosimeter
pada dos sinaran rendah di dalam radioterapi klinikal. Kata kunci: Gel polimer; HEMAG; jalur
tenaga optik; sifat optik; spektrofotometer UV-vis;
tenaga Urbach RUJUKAN Chahal,
R.P. 2011. Effect of ultraviolet irradiation on the optical and
structural characteristics of in-situ prepared PVP-Ag nanocomposites.
Digest Journal of Nanomaterials and Biostructures 6(1):
299-306. Cho,
S.J., Shin, D., Huh, H.D., Lee, S.H., Lim, S.W., Yun, H.G., Yun,
S.M., Shin, D.O., Yang, D.S., Park, Y.J., Kim, C.Y. & Lee,
S. 2007. Development of a novel normoxic polymer gel dosimeter
(TENOMAG). Journal of the Korean Physical Society 51(5):
1798-1804. Elias
Saion, Susilawati, Doyan, A., Zainal Abidin, S., Azmi, Z., Zulkfli,
A., Mohd Zaki, A.R., Dahlan, K.Z.H. & Karni, T. 2005. Changes
in the optical band gap and absorption edge of gamma-irradiated
polymer blends. Journal of Applied Sciences 5(10): 1825-1829.
Hawkins,
A.R. & Holger, S. 2010. Handbook of Optofluidics. New
York: Taylor & Francis Group. doi:10.1038/ncomms1662. Maryanski,
M.J., Zastavker, Y.Z. & Gore, J.C. 1996. Radiation dose distributions
in three dimensions from tomographic optical density scanning
of polymer gels: II. Optical properties of the BANG polymer gel
radiation dose distributions in three dimensions from tomographic
optical density scanning of poly. Physic in Medicine and Biology
41: 2705-2717. Podgorsak,
E. 2005. Radiation Oncology Physics: A Handbook for Teachers
and Students. International Atomic Energy Agency. doi:10.1038/sj.bjc.6604224.
Susilawati
& Doyan, A. 2009. Dose response and optical properties of
dyed poly vinyl alcohol-trichloroacetic acid polymeric blends
irradiated with gamma-rays. American Journal of Applied Sciences
6(12): 2071-2077. *Pengarang untuk surat-menyurat; email: sitiatiqah.ishak@gmail.com
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