Verifikasi Distribusi Dosis pada High-Dose-Rate Brachytherapy (HDR-BT) Berdasarkan Protokol AAPM TG-43: Studi Kasus Fantom Serviks Spesifik

Nur'azizah, Siti (2026) Verifikasi Distribusi Dosis pada High-Dose-Rate Brachytherapy (HDR-BT) Berdasarkan Protokol AAPM TG-43: Studi Kasus Fantom Serviks Spesifik. Masters thesis, Institut Teknologi Sepuluh Nopember.

Text 6001232001-Master_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (2MB) | Request a copy

Abstract

Penerapan High-Dose-Rate Brachytherapy (HDR-BT) Co-60 pada kanker serviks sering kali menghadapi tantangan akurasi dosis akibat penggunaan protokol AAPM TG-43 pada Treatment Planning System (TPS). Protokol tersebut mengasumsikan tubuh pasien sebagai medium air homogen, seringkali mengabaikan heterogenitas jaringan dan kompleksitas anatomi yang sebenarnya. Hal ini beresiko memicu perbedaan antara dosis yang direncanakan dengan dosis yang diterima pasien. Penelitian ini mengevaluasi distribusi dosis TPS SagiPlan melalui perbandingan langsung dengan film Gafchromic EBT4. Metode eksperimen dilakukan menggunakan fantom serviks berbahan polylactic acid (PLA) yang dirancang khusus secara anatomis. Dengan dosis resep sebesar 7 Gy, pengujian dilakukan pada tiga variasi diameter aplikator silinder (20, 25, dan 30 mm). Parameter evaluasi mencakup titik kontrol di permukaan aplikator, High Risk-Clinical Target Volume (HR-CTV), serta Organ at Risk (OAR) yang mencakup rektum, kandung kemih, uterus, sigmoid, dan bowel. Hasil penelitian menunjukkan bahwa TPS SagiPlan secara konsisten mengestimasi dosis lebih tinggi dibandingkan dosis terukur. Rata-rata deviasi dosis pada permukaan aplikator masing-masing sebesar 7,194% untuk diameter 30 mm, 6,273% untuk 25 mm, dan 5,977% untuk 20 mm. Pada HR-CTV, rata-rata deviasi dosis titik kontrol berada pada kisaran 5,938% hingga 6,747%, sedangkan pada OAR nilai deviasi berkisar antara 5,749% hingga 8,575%, bergantung pada jenis organ dan lokasi titik ukur. Hasil ini menunjukkan bahwa pengaruh keterbatasan algoritma TG-43 paling menonjol pada area dengan gradien dosis tinggi di sekitar sumber, khususnya pada permukaan aplikator, sementara kesesuaian dosis pada HR-CTV dan OAR masih berada dalam batas toleransi ±10%.
================================================================================================================================
The application of High-Dose-Rate Brachytherapy (HDR-BT) Co-60 in cervical cancer often faces challenges in dose accuracy due to the use of the AAPM TG-43 protocol in the Treatment Planning System (TPS). This protocol assumes the patient's body to be a homogeneous water medium, often ignoring tissue heterogeneity and actual anatomical complexity. This risks triggering discrepancies between the planned dose and the dose received by the patient. This study evaluated the dose distribution of the SagiPlan TPS through direct comparison with Gafchromic EBT4 film. The experimental method was carried out using a polylactic acid (PLA) cervical phantom that was specially designed to anatomical specifications. With a prescription dose of 7 Gy, testing was performed on three variations of cylindrical applicator diameters (20, 25, and 30 mm). Evaluation parameters included control points on the applicator surface, High-Risk Clinical Target Volume (HR-CTV), and Organs at Risk (OAR) covering the rectum, bladder, uterus, sigmoid, and bowel. The results showed that TPS SagiPlan consistently estimated higher doses than the measured doses. The average dose deviation on the applicator surface was 7,194% for a diameter of 30 mm, 6,273% for a diameter of 25 mm, and 5,977% for a diameter of 20 mm. In HR-CTV, the average control point dose deviation ranged from 5,938% to 6,747%, while in OAR, the deviation ranged from 5,749% to 8,575%, depending on the type of organ and measurement point location. These results show that the limitations of the TG-43 algorithm are most pronounced in areas with high dose gradients around the source, particularly on the applicator surface, while dose conformity in HR-CTV and OAR remains within the ±10% tolerance limit.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	AAPM TG-43, Co-60, Deviasi Dosis, Film Gafchromic EBT4, Fantom Serviks, dan HDR-BT.AAPM TG-43, Co-60, Dose Deviation, Gafchromic EBT4 Film, Cervical Phantom, HDR-BT
Subjects:	Q Science > QC Physics Q Science > QC Physics > QC795.5 Radioactivity and radioactive Instruments and apparatus (General)
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Physics > 45101-(S2) Master Thesis
Depositing User:	Siti Nur'azizah
Date Deposited:	04 Feb 2026 04:22
Last Modified:	04 Feb 2026 04:22
URI:	http://repository.its.ac.id/id/eprint/132004

Actions (login required)

View Item