Sains Malaysiana 44(8)(2015): 1145–1151
Evaluation of Organ at Risk (OAR) Doses based on 2D Treatment Planning
in Intracavitary Brachytherapy of Cervical Cancer
(Penilaian
Dos Organ Berisiko berdasarkan Perancangan Rawatan 2 Dimensi Brakiterapi
Intrarongga bagi Kanser Servik)
REDUAN
ABDULLAH1*,
NUR
AQILAH
ABDUL
SANI1,
CHEN
SUK
CHIANG1,
MAZURAWATI
MOHAMED2,
NIK
RUZMAN
NIK
IDRIS2,
AHMAD
LUTFI
YUSOFF2
& BHAVARAJU VMK2
1School of Health Sciences,
Health Campus, Universiti Sains Malaysia, 11800 Kubang Kerian, Kelantan
Darul Naim, Malaysia
2Department of Nuclear
Medicine, Radiotherapy and Oncology, School of Medical Sciences,
Universiti Sains Malaysia, 11800 Kubang Kerian, Kelantan Darul Naim,
Malaysia
Diserahkan: 28 Januari
2015/Diterima: 31 Mac 2015
ABSTRACT
Conventional two-dimensional
(2D) treatment planning of intracavitary brachytherapy is still
a common practice at the radiotherapy center. The purpose of this
study was to evaluate the organ at risk (OAR) doses estimated based on
International Commission on Radiation Units and Measurements (ICRU)
reference-point in patients with cervical cancer treated with high-dose-rate
(HDR)
intracavitary brachytherapy (ICBT). Between January 2010 and
April 2014, 21 cervical cancer patients were treated with 42 fractions
of brachytherapy using tandem and ovoids and underwent post-implant
two-dimensional (2D) radiograph scans. HDR brachytherapy was delivered
to a dose of 18 Gy in two fractions. Using the Oncentra brachytherapy
treatment planning system (BTPS) software version 4.1 (Nucletron,
Netherlands), the bladder and rectum points were retrospectively
reconstructed based on 42 orthogonal radiographs datasets. The ICRU bladder
and rectum point doses were recorded. As for results, the mean percentage
dose of rectum and bladder for selected patients treated with intracavitary
brachytherapy treatment (ICBT) were 47.27 and 75.59%, respectively.
Combinations of ovoid’s size, length of tandem and anatomy variation
between each patient were factors that affected the dose to the
OAR.
Therefore, the ICRU reference points can still be used
with the 2D brachytherapy treatment planning in evaluating the OAR
doses.
Keywords: International
Commission on Radiation Units and Measurements (ICRU)
reference points; intracavitary brachytherapy treatment (ICBT);
organ at risk (OAR) doses; two-dimensional (2D) treatment
planning
ABSTRAK
Perancangan konvensional
dua dimensi (2D) rawatan brakiterapi intrarongga masih merupakan
amalan biasa di sesetengah pusat radioterapi. Tujuan kajian retrospektif
ini dijalankan adalah untuk menilai dos pada organ berisiko (OAR)
berdasarkan syor oleh Suruhanjaya Antarabangsa mengenai Unit Sinaran
dan Pengukuran (ICRU) pada pesakit dengan kanser serviks dirawat dengan
dos berkadar tinggi (HDR) brakiterapi intrarongga (ICBT).
Antara Januari 2010 dan April 2014, 21 pesakit kanser serviks telah
dirawat dengan 42 pecahan brakiterapi menggunakan tandem dan ovoid
serta menjalani imbasan dua dimensi (2D) radiografi pasca-implan.
Dos rawatan HDR brakiterapi
yang digunakan adalah sebanyak 18 Gy dalam dua fraksi. Menggunakan
perancangan rawatan brakiterapi Oncentra perisian 4.1 (Nucletron,
Netherlands), titik pundi kencing dan rektum telah ditandakan semula
pada 42 radiografi ortogonal dalam kajian retrospektif ini. Hasil
kajian menunjukkan peratusan dos purata rektum dan pundi kencing
bagi pesakit dipilih dirawat dengan ICBT masing-masing
47.27 dan 75.59%. Kombinasi saiz ovoid, panjang tandem dan anatomi
yang berbeza antara pesakit merupakan beberapa faktor yang memberi
kesan dos terhadap OAR.
Oleh itu, titik rujukan ICRU dalam 2D perancangan rawatan brakiterapi
masih boleh digunakan untuk menganggar dos OAR.
Kata kunci: Dos pada
organ berisiko (OAR); mata rujukan Suruhanjaya
Antarabangsa mengenai Unit Sinaran dan Pengukuran (ICRU);
perancangan rawatan dua dimensi (2D); rawatan brakiterapi intrarongga
(ICBT)
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*Pengarang
untuk surat-menyurat; email: reduan@usm.my
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