Evaluasi Risiko Radiation-Induced Second Malignant (RISM) Pada Pasien Kanker Payudara Dengan Nilai Total Dosis Penerimaan Menggunakan Metode IMRT

Al-Hakim, Sayyid (2026) Evaluasi Risiko Radiation-Induced Second Malignant (RISM) Pada Pasien Kanker Payudara Dengan Nilai Total Dosis Penerimaan Menggunakan Metode IMRT. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kanker payudara merupakan kasus kanker dengan insiden tertinggi di Indonesia, dan radioterapi IMRT menjadi salah satu modalitas pengobatan utamanya. Namun, Treatment Planning System (TPS) konvensional hanya menghitung dosis in-field dan mengabaikan kontribusi hamburan sekunder atau out-of-field serta dosis pencitraan imaging dose dari pCT maupun CBCT sehingga dapat memunculkan resiko Radiation-Induced Second Malignant (RISM). Penelitian ini mengevaluasi nilai total dosis integratif dari ketiga komponen tersebut serta memprediksi probabilitas RISM pada 10 pasien kanker payudara 5 kiri dan 5 kanan di RSUD dr. Mohamad Soewandhie. In-field dose diekstraksi dari TPS, out-of-field dose dihitung menggunakan PERIPOCHAL 3D, dan imaging dose diestimasi melalui WAZA-ARI serta simulasi Monte-Carlo, kemudian diintegrasikan secara mean dose organ dan menganalisis Dose-Volume Histogram (DVH) total pada Organ at Risk (OAR) dan organ yang tidak direncanakan. Risiko RISM dihitung dengan Lifetime Attributable Risk (LAR). Pada organ in-field, nilai dosis organ target 50,7–51,4 Gy (TPS) dan 50,5–51,2 Gy (total), sedangkan payudara kontralateral 4,2–4,9 Gy pada kedua metode. Pada organ out-of-field, dosis duodenum naik dari 0,3 Gy (TPS) menjadi 0,55 Gy (total) dan usus halus dari 0,22 menjadi 0,5 Gy. Penambahan out-of-field dose dan imaging dose hampir tidak mengubah bentuk DVH pada organ in-field, tetapi menggeser kurva DVH pada out-of-field dose. Nilai LAR sejalan dengan pola tersebut: payudara kontralateral 1,31 sampai 1,34 kali pada kasus kanker payudara kiri dan 1,67 sampai 1,76 kali pada kasus kanker payudara kanan, sementara organ di luar lapangan meningkat jauh lebih tinggi, dengan rasio kolon hingga 2,98 kali dan usus halus hingga 3,31 kali.
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Breast cancer has the highest incidence in Indonesia, and IMRT radiotherapy is a primary treatment modality. However, conventional treatment planning systems (TPS) only calculate the primary (in-field) dose and neglect the contribution of secondary scattered radiation (out-of-field) and imaging doses from pCT and CBCT, even though the accumulation of low-dose radiation in healthy organs can trigger secondary malignancies or radiation-induced second malignancies (RISM). This study evaluated the integrative total dose of these three components and predicted the RISM probability in 10 breast cancer patients (five left-sided and five right-sided) at RSUD dr. Mohamad Soewandhie. The in-field dose was extracted from the TPS, the out-of-field dose was calculated using PERIPHOCAL 3D (MATLAB), and the imaging dose was estimated through WAZA-ARI and Monte Carlo simulation, then integrated voxel-by-voxel to analyze the total dose-volume histogram (DVH) of the organs at risk (OARs). The RISM risk was quantified using the lifetime attributable risk (LAR) method. For in-field organ target-organ dose was 50.7–51.4 Gy (TPS) and 50.5–51.2 Gy (total), and the contralateral breast was 4.2–4.9 Gy under both methods. For out-of-field organs, the duodenum dose range was 0.3 Gy (TPS) to 0.55 Gy (total), and the small intestine was 0.22 to 0.5 Gy. Adding the out-of-field and imaging doses barely altered the DVH shape of the in-field organs but shifted the DVH curve for the out-of-field organs. The LAR followed the same pattern: the contralateral breast risk was approximately 1.31 to 1.34 times higher in the left-sided case and 1.67 and 1.76 times higher in the right-sided case, while the out-of-field organs increased significantly, with colon ratios up to 2.98 times and the small intestine up to 3.31-fold.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	IMRT, Kanker Payudara, Lifetime Attributable Risk, Nilai Total Dosis, RISM
Subjects:	Q Science > QC Physics > QC795.5 Radioactivity and radioactive Instruments and apparatus (General)
Divisions:	Faculty of Natural Science > Physics > 45201-(S1) Undergraduate Thesis
Depositing User:	Sayyid Al Hakim
Date Deposited:	28 Jul 2026 06:24
Last Modified:	28 Jul 2026 06:24
URI:	http://repository.its.ac.id/id/eprint/137609

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