Pengaruh Densitas Elektron Jaringan Kanker Terhadap Distribusi Dosis Radioterapi Menggunakan TPS Klinis dan Simulasi Software PRIMO

Terapi radiasi pada kasus kanker payudara kanan pasca-mastektomi (PMRT) dilakukan untuk mencegah kekambuhan kanker payudara dan menurunkan resiko penyebaran kanker di sekitar payudara. Telah dikembangkan phantom thorax 3D PMRT pada pengerjaan sebelumnya namun belum dilengkapi dengan metastasis kanker payudara pasca-mastektomi. Penelitian ini memperbaharui phantom tersebut dengan memfabrikasi metastasis kanker payudara tiruan yang memiliki karakteristik menyerupai jaringan kanker sebenarnya. Bahan pengganti jaringan kanker divariasi berdasarkan densitas elektron dan dipelajari pengaruhnya terhadap distribusi dosis yang dihasilkan. Penelitian ini dimulai dari fabrikasi pembaharuan phantom thorax 3D PMRT, pembuatan jaringan kanker tiruan, pemindaian CT, pembuatan sistem perencanaan perawatan (TPS) secara klinis dengan teknik IMRT dan berkas foton energi 6 MV, proses simulasi TPS melalui software PRIMO, dan evaluasi TPS hasil simulasi PRIMO dengan TPS klinis. Hasil analisis CT Number dan Relative Electron Density (RED) menunjukkan bahwa bahan yang dapat digunakan untuk mensimulasikan metastasis kanker payudara pasca-mastektomi adalah agar-agar, gelatin, dan agarose. Faktor tegangan tabung CT scan tidak mempengaruhi nilai densitas elektron relatif namun mempengaruhi rentang CT Number (HU) dan kualitas citra CT yang dihasilkan. Selain itu, dari hasil analisis dosimetri diperoleh bahwa distribusi dosis radioterapi tidak dipengaruhi secara signifikan oleh perbedaan densitas elektron. Hasil TPS klinis bersesuaian dengan TPS simulasi PRIMO karena diperoleh pola distribusi dosis yang mirip. Oleh karena itu, dapat disimpulkan bahwa PRIMO merupakan software yang cukup baik untuk mensimulasikan TPS meskipun keakuratan dosisnya belum maksimal dibandingkan kalkulasi TPS klinis. ================================================================================================= Radiation therapy in post-mastectomy right breast cancer (PMRT) prevents breast cancer recurrence and reduces the risk of spreading cancer around the breast. The 3D PMRT thorax phantom has been developed in the previous work has not been equipped with post-mastectomy breast cancer metastases. This study improves the phantom by fabricating artificial breast cancer metastases that have characteristics resembling actual cancer tissue. Cancer tissue substitute materials were varied based on their electron density, and their effect on the resulting dose distribution was studied. This research started from the fabrication of the 3D PMRT thorax phantom renewal, fabrication of artificial cancer tissue, CT scanning, clinical treatment planning system (TPS) with IMRT technique and 6 MV photon energy, TPS simulation process through PRIMO software, and evaluation of PRIMO TPS with clinical TPS. Analysis of the CT Number and Relative Electron Density (RED) showed that the materials that could be used to simulate post-mastectomy breast cancer metastases were agar-agar, gelatin, and agarose. The CT scan tube voltage does not affect the relative electron density value but the range of CT Number (HU) and the quality of the resulting CT image. In addition, from the dosimetry analysis, it was found that the radiotherapy dose distribution was not significantly affected by differences in electron density. The results of the TPS from the PRIMO simulation were in agreement with the clinical TPS because a similar pattern of dose distribution was obtained. Therefore, it can be concluded that PRIMO is a reasonably good software for simulating TPS even though the accuracy of the dose is not maximized compared to clinical TPS calculations