Pengaruh Grid Size Pada Kalkulasi Algoritma AAA Terhadap Dosimetri Dan Radiobiologi Menggunakan VMAT Pada Karsinoma Nasofaring

Ilma, Firda Zaidah (2026) Pengaruh Grid Size Pada Kalkulasi Algoritma AAA Terhadap Dosimetri Dan Radiobiologi Menggunakan VMAT Pada Karsinoma Nasofaring. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Karsinoma nasofaring (KNF) merupakan salah satu keganasan kepala-leher yang cukup banyak ditemukan di Asia Tenggara, termasuk Indonesia, dengan angka kematian yang masih tinnggi. Radioterapi Volumetric Modulated Arc Therapy (VMAT) sebagai modalitas penanganan utama dalam kasus ini. Akurasi kalkulasi dosis pada algoritma Anisotropic Analytical Algorithm (AAA) dipengaruhi oleh resolusi grid, sehingga pemilihan grid size menjadi kunci ketepatan dosis pada anatomi nasofaring yang kompleks dan heterogen. Penelitian ini mengevaluasi pengaruh variasi grid size terhadap dosis PTV, OAR, serta parameter radiobiologi TCP dan NTCP pada perencanaan VMAT kanker nasofaring. Enam variasi grid size (1; 2; 2,5; 3; 4; dan 5 mm) diterapkan pada 12 pasien KNF VMAT di RSUD dr. Mohamad Soewandhie menggunakan TPS Eclipse dengan grid 2,5 mm sebagai default TPS, mencakup Homogeneity Index (HI), dan Conformity Index (CI) pada PTV, Dmax/Dmin OAR, serta TCP dan NTCP. Hasil menunjukkan grid size AAA berpengaruh signifikan terhadap HI, CI, TCP, dan NTCP pada perencanaan VMAT karsinoma nasofaring dengan grid baru bermakna pada selisih ≥3–4 mm. Sensitivitas OAR bergantung pada jarak ke PTV dan parameter α model EUD, di mana organ kecil dekat zona dosis tinggi paling terpengaruh meski umumnya masih dalam batas toleransi. Grid 2 mm terbukti setara dengan grid default 2,5 mm pada hampir seluruh parameter dosimetri.
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Nasopharyngeal carcinoma (NPC) is one of the head and neck malignancies that is fairly commonly found in Southeast Asia, including Indonesia, with a mortality rate that remains high. Radiotherapy using Volumetric-Modulated Arc Therapy (VMAT) serves as the main treatment modality for this condition. The accuracy of dose calculation using the anisotropic analytical algorithm (AAA) is influenced by grid resolution, making grid size selection key to dose accuracy given the complex and heterogeneous anatomy of the nasopharynx. This study evaluated the effect of grid size variation on the dose of the PTV, OARs, as well as the radiobiological parameters tumor control probability (TCP) and normal tissue complication probability (NTCP) in VMAT planning for nasopharyngeal cancer. Six grid size variations (1, 2, 2.5, 3, 4, and 5 mm) were applied to 12 NPC VMAT patients at RSUD dr. Mohamad Soewandhie using the Eclipse TPS, with 2.5 mm as the TPS default grid size, Homogeneity Index (HI), and Conformity Index (CI) for the PTV, Dmax/Dmin for OARs, as well as TCP and NTCP. The results showed that AAA grid size significantly affected HI, CI, TCP, and NTCP in VMAT planning for nasopharyngeal carcinoma, with the difference becoming significant at a grid size of ≥3–4 mm. OAR sensitivity depended on the distance to the PTV and the α parameter in the EUD model, with small organs near high-dose regions being most affected, although most remained within tolerance limits. A 2 mm grid was found to be equivalent to the default 2.5 mm grid for nearly all dosimetric parameters.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	AAA, Grid Size, Karsinoma Nasofaring, NTCP, TCP. AAA, Grid size, nasopharyngeal carcinoma, NTCP, TCP.
Subjects:	Q Science Q Science > QC Physics Q Science > QC Physics > QC795.5 Radioactivity and radioactive Instruments and apparatus (General)
Divisions:	Faculty of Mathematics and Science > Physics > 45201-(S1) Undergraduate Thesis
Depositing User:	Firda Zaidah Ilma
Date Deposited:	04 Aug 2026 08:42
Last Modified:	04 Aug 2026 08:42
URI:	http://repository.its.ac.id/id/eprint/143502

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