Pengaruh Sudut Kolimator Terhadap Kualitas Perencanaan Dan Distribusi Dosis Pada Terapi Kanker Nasofaring Menggunakan Volumetric Modulated Arc Therapy (VMAT)

Putri, Astrid Arsawati (2026) Pengaruh Sudut Kolimator Terhadap Kualitas Perencanaan Dan Distribusi Dosis Pada Terapi Kanker Nasofaring Menggunakan Volumetric Modulated Arc Therapy (VMAT). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kanker nasofaring menempati peringkat pertama keganasan kepala dan leher di Indonesia dengan penatalaksanaan utama berupa radioterapi Volumetric Modulated Arc Therapy (VMAT). Pengaturan sudut kolimator Multi-Leaf Collimator (MLC) menjadi solusi dalam meminimalkan kebocoran radiasi sekaligus meningkatkan kualitas distribusi dosis. Penelitian ini bertujuan mengevaluasi pengaruh sudut kolimator terhadap kualitas perencanaan dan distribusi dosis pada terapi kanker nasofaring menggunakan VMAT. Tiga rencana VMAT dibuat pada 27 pasien, yaitu rencana A (0°/90°), B (30°/120°), dan C (30°/330°). Titik akhir dosimetrik meliputi Conformity Index (CI), Homogeneity Index (HI), distribusi dosis di OAR, Monitor Unit (MU), serta Gamma Passing Rate (GPR). Hasil menunjukkan bahwa sudut kolimator rencana A memberikan berpengaruh signifikan terhadap HI yang lebih baik, namun memberikan cakupan dosis yang sama di semua rencana. Rencana A unggul dalam penghematan dosis sumsum tulang belakang dan parotid kanan, rencana C penghematan dosis di organ laring, dan tidak terdapat perbedaan signifikan untuk semua rencana pada dosis di batang otak, koklea, mata, rongga mulut, parotid kiri, dan lobus temporal (p > 0,05). Rencana B menunjukkan efisien pengiriman lebih baik dengan MU terendah dan paling konsisten. Verifikasi EPID menunjukkan rencana B memberikan hasil QA yang baik dengan nilai GPR tertinggi dan paling konsisten hingga kriteria 2%/1mm.
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Nasopharyngeal cancer is the most prevalent head and neck cancer in Indonesia, and the main treatment is volumetric-modulated arc therapy (VMAT). Adjusting the multi-leaf collimator (MLC) angles helps reduce radiation leakage while boosting the dose distribution quality. This study investigated how collimator angles affect treatment planning and dose distribution in nasopharyngeal cancer using VMAT. Three VMAT plans were created for 27 patients: plan A (0°/90°), plan B (30°/120°), and plan C (30°/330°). The dosimetric endpoints included conformity index (CI), homogeneity index (HI), dose distribution in the PTV and OARs, monitor unit (MU), and gamma passing rate (GPR). The results showed that the collimator angle in plan A had a significant effect on achieving a better HI, but it provided the same dose coverage across all plans. Plan A was better at saving doses to the spinal cord and right parotid, plan C saved dose in the larynx, and there was no significant difference among all plans for doses to the brainstem, cochlea, eyes, oral cavity, left parotid, and temporal lobes (p > 0.05). Plan B showed better delivery efficiency with the lowest and most consistent MU. EPID verification showed that plan B provided good QA results with the highest and most consistent GPR up to the 2%/1 mm criteria.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Multi Leaf Collimator, Sudut Kolimator, VMAT, collimator angle, multi-leaf collimator, VMAT.
Subjects:	Q Science > QC Physics > QC795.5 Radioactivity and radioactive Instruments and apparatus (General)
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Physics > 45201-(S1) Undergraduate Thesis
Depositing User:	Astrid Arsawati Putri
Date Deposited:	28 Jul 2026 01:00
Last Modified:	28 Jul 2026 01:00
URI:	http://repository.its.ac.id/id/eprint/137927

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