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"Gerak tumor akibat pernapasan pasien merupakan masalah yang signifikan dalam pengobatan radioterapi kanker paru-paru, khususnya teknik radioterapi modern Intensity Modulated Radiotherapy (IMRT) dan Volumetric Modulated Arc Therapy (VMAT). Interaksi gerakan antara gerak target tumor dan MLC (interplay effect) memiliki keterbatasan dalam hal modulasi intensitas radiasi, probabilitasnya hanya sebagian kecil Planning Target Volume (PTV) menerima dosis radiasi sesuai perencanaan dosis Treatment Planning System (TPS) pada waktu tertentu.Penelitian ini melakukan verifikasi dosimetri antara dosis yang direncanakan TPS dan dosis yang diterima volume tumor, akibat adanya interplay effect pada teknik IMRT dan VMAT. Penelitian menggunakan fantom toraks dinamik in-house dengan target tumor bergerak translasi arah superior-inferior dengan variasi amplitudo dan periode gerak tumor sebesar 9,3 mm dan 2,3 sekon, 20 mm dan 3,44 sekon, 30 mm dan 4,22 sekon. Pengukuran dosis titik dengan meletakkan dosimeter TLD-100 LiF:Mg,Ti dan Film Gafchromic EBT2 pada titik tengah target tumor dan organ at risk spinal cord. Penyinaran teknik IMRT menggunakan 7-field dan teknik VMAT menggunakan Rapidarc partial double arc dengan dosis preskripsi (95%) sebesar 200 cGy per fraksi.Hasil penelitian menunjukkan bahwa kehadiran gerak target tumor paru-paru menyebabkan efek dosimetri yang tidak diinginkan berupa underdosage dalam volume tumor. Deviasi dosis rata-rata pada target tumor antara perencanaan dosis TPS dan hasil pengukuran pada teknik IMRT dengan target tumor bergerak statis, bergerak 9,3 mm, bergerak 20 mm, bergerak 30 mm berturut-turut sebesar 0,3% sampai 0,5%, -2,7% sampai -3,0%, -3,7% sampai -4,6%, dan -6,0% sampai -6,6%, sedangkan deviasi dosis pada teknik VMAT berturut-turut sebesar 0,2% sampai 0,9%, -1,6% sampai -1,9%, -2,9% sampai -3,1%, dan -5,0% sampai -5,3%. Hal berbeda, deviasi dosis untuk organ at risk spinal cord pada teknik IMRT berturutturut sebesar -5,6% sampai -1,0%, -6,8% sampai -6,9%, -3,7% sampai -5,9%, dan 0,7% sampai 1,0%, sedangkan deviasi dosis pada teknik VMAT berturut-turut sebesar -1,4% sampai -3,1%, -3,0% sampai -6,3%, -1,6% sampai -4,2%, dan 0,1% sampai 0,9%. Kenaikan amplitudo gerak target tumor menyebabkan dosis yang diterima volume tumor menurun. Namun sebaliknya, adanya kenaikan amplitudo gerak target tumor menyebabkan dosis yang diterima organ at risk spinal cord meningkat.

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Tumor motion due to patient's respiratory is a significant problem in radiotherapy treatment of lung cancer, especially in modern radiotherapy treatment of Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT). The interplay effect is the effect that may occur as the motion of Linac (primarily the MLC) and motion of the tumor target interferes. At delivery dose treatment, a small part of Planning Target Volume (PTV) does not recover dose according to Treatment Planning System (TPS) Prescription.

This investigation was carried out through dosimetry verification between TPS and actual dose by tumor volume due to the interplay effect in IMRT and VMAT treatment. Tumor target of in-house dynamic thorax phantom was designed in linier sinusoidal motion toward superior-inferior direction with amplitude and period variation of tumor motion of 9,3 mm and 2,3s, 20 mm and 3,44s, 30 mm and 4,22s respectively. For point dose measurement, TLD-100 LiF:Mg,Ti and gafchromic EBT2 film detectors were took placed at midpoint of tumor target and spinal cord. IMRT treatment irradiation was applied by 7-fields and VMAT treatment by partial double arc, with prescription dose (95%) of 200 cGy per fraction.

The results showed that the occurrence of lung tumor target motion causes underdosage dosimetry effect in tumor volume. Mean dose deviation of tumor target between TPS and measurement in IMRT treatment by tumor target moves at condition of static, 9,3 mm, 20 mm and 30 mm were 0,3% to 0,5%, -2,7% to -3,0%, -3,7% to -4,6%, and -6,0% to -6,6% respectively while dose deviation in VMAT treatment were 0,2% to 0,9%, -1,6% to -1,9%, -2,9% to -3,1%, and -5,0% to -5,3% respectively. On the other hand, mean dose deviation of spinal cord in IMRT treatment were -5,6% to -1,0%, -6,8% to -6,9%, -3,7% to -5,9%, and 0,7% to 1,0% respectively and in VMAT treatment were -1,4% to -3,1%, -3,0% to -6,3%, -1,6% to -4,2%, and 0,1% to 0,9% respectively. The increment amplitude of tumor target motion reduced dose received by tumor volume and conversely, increased dose received by spinal cord."

"[ABSTRAKTujuan dari penelitian ini adalah mengevaluasi akurasi perencanaan danpemberian perlakuan volumetric modulated arc therapy (VMAT) menggunakanrekomendasi AAPM Task Group (TG) 119 di Departemen Radioterapi MRCCCSiloam Hospitals Semanggi. TG 119 menetapkan dua tes pendahuluan dan limates menyerupai kondisi klinis, serta confidence limit (CL) sebagai nilai standarpengujian. Perencanaan intensity modulated radiation therapy (IMRT) danVMAT dibuat lokal mengikuti preskripsi dosis dan sasaran perencanaan yangditetapkan oleh TG 119, kemudian hasil perencanaan lokal dibandingkan denganhasil TG 119. Pengukuran dosis titik dari pemberian perlakuan IMRT dan VMATpada daerah dosis tinggi dan rendah diukur menggunakan tiga bilik ionisasidengan volume aktif yang berbeda, sedangkan pengukuran dosis penampangmenggunakan detektor 2D array, distribusi dosis penampang dianalisa dengankriteria indeks gamma 3 %, 3 mm dan 2 %, 2 mm. CL hasil pengukuran dosis titikIMRT pada daerah dosis tinggi dan rendah 1.06 % dan 0.82 % (CC01), 1.19 %dan 1.58 % (CC13), 1.37 % dan 3.02 % (FC65G). Untuk VMAT 1.47 % dan 1.17% (CC01), 1.71 % dan 1.95 % (CC13), 2.08 % dan 3.96 % (FC65G). Hasilpengukuran menggunakan bilik ionisasi CC01 dan CC13 mampu memenuhikriteria yang ditetapkan TG 119 dibawah 3 %, sedangkan bilik ioisasi FC65Gtidak memenuhi kriteria tersebut. Hasil CL analisa indeks gamma IMRT dengankriteria gamma 3 %, 3 mm dan 2 %, 2mm sebesar 3.68 dan 11.71 (96.32 % dan88.29 % pass), sedangkan untuk VMAT sebesar 1.44 dan 6.33 (98.56 % dan93.67 % pass), kedua hasil indeks gamma tersebut masuk dalam kriteria TG 119dibawah 12.4. Berdasarkan hasil tersebut, rekomendasi TG 119 dapatdiimplementasikan untuk menguji akurasi perencanaan dan pemberian perlakuanVMAT, hasil tersebut juga menunjukkan keakurasian yang cukup dariperencanaan dan pemberian perlakuan VMAT di institusi lokal.

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ABSTRACTThe purpose of this study was to evaluate the accuracy of treatment planning anddelivery of Volumetric Modulated Arc Therapy (VMAT) using recommendationof AAPM Task Group (TG) 119 in the Department of Radiotherapy MRCCCSiloam Hospitals Semanggi. TG 119 establishes two preliminary tests and fivetests resemble a clinical condition, as well as the confidence limit (CL) as abenchmark data. Dose prescriptions and planning objectives recommended by TG119 report were followed to generate Intensity Modulated Radiation Therapy(IMRT) and VMAT treatment planning, and then the local planning resultscompared with the results of TG 119. Point dose measurements were done usingthree ionization chambers with different active volume at high dose and low doseregions. The planar dose measurements were measured using a 2D detector arrayand the planar dose distribution was analyzed for percentage of points passing thegamma criteria of 3 %, 3 mm and 2 %, 2 mm. For IMRT plans, the CLs obtainedfor point dose measurement in areas of high and low doses were 1.06 % and 0.82% (CC01), 1.19 % and 1.58 % (CC13), 1.37 and 3.02 % (FC65G), whereas avalue of 1.47 and 1.17 % (CC01), 1.71 % and 1.95 % (CC13), 2.08 % and 3.96 %(FC65G) for CL VMAT. Point dose measurement results using ion chamberCC01 and CC13 were able to meet the criteria set by TG 119 below 3 %, whilefor ion chamber FC65G could not meet these criteria. From gamma analysis, CLIMRT for gamma criteria 3 %, 3 mm and 2 %, 2 mm were 3.68 and 11.71 (96.32% and 88.29 % pass), while for VMAT were 1.44 and 6.33 (98.56 % and 93.67 %pass), gamma index results falls within the criteria TG 119 under 12.4. Based onthe results, TG 119 recommendations can be implemented on commissioningVMAT treatment planning and delivery, these results also indicate adequateaccuracy of VMAT treatment planning and delivery in local institution, The purpose of this study was to evaluate the accuracy of treatment planning anddelivery of Volumetric Modulated Arc Therapy (VMAT) using recommendationof AAPM Task Group (TG) 119 in the Department of Radiotherapy MRCCCSiloam Hospitals Semanggi. TG 119 establishes two preliminary tests and fivetests resemble a clinical condition, as well as the confidence limit (CL) as abenchmark data. Dose prescriptions and planning objectives recommended by TG119 report were followed to generate Intensity Modulated Radiation Therapy(IMRT) and VMAT treatment planning, and then the local planning resultscompared with the results of TG 119. Point dose measurements were done usingthree ionization chambers with different active volume at high dose and low doseregions. The planar dose measurements were measured using a 2D detector arrayand the planar dose distribution was analyzed for percentage of points passing thegamma criteria of 3 %, 3 mm and 2 %, 2 mm. For IMRT plans, the CLs obtainedfor point dose measurement in areas of high and low doses were 1.06 % and 0.82% (CC01), 1.19 % and 1.58 % (CC13), 1.37 and 3.02 % (FC65G), whereas avalue of 1.47 and 1.17 % (CC01), 1.71 % and 1.95 % (CC13), 2.08 % and 3.96 %(FC65G) for CL VMAT. Point dose measurement results using ion chamberCC01 and CC13 were able to meet the criteria set by TG 119 below 3 %, whilefor ion chamber FC65G could not meet these criteria. From gamma analysis, CLIMRT for gamma criteria 3 %, 3 mm and 2 %, 2 mm were 3.68 and 11.71 (96.32% and 88.29 % pass), while for VMAT were 1.44 and 6.33 (98.56 % and 93.67 %pass), gamma index results falls within the criteria TG 119 under 12.4. Based onthe results, TG 119 recommendations can be implemented on commissioningVMAT treatment planning and delivery, these results also indicate adequateaccuracy of VMAT treatment planning and delivery in local institution]"

"Telah dilakukan verifikasi dosis organ target dan jaringan sehat di sekitar target dengan menempatkan TLD Rod LiF100 dan film Gafchromic EBT2 di lubang slab bagian pelvis dari phantom Rando Alderson untuk simulasi kanker prostat. TLD dievaluasi menggunakan TLD Reader Harshaw, sementara Film Gafchromic EBT2 dipindai menggunakan scanner Epson Perfection V700 dengan mode transmisi, red channel dan resolusi 72 dpi. Pengukuran dosis titik dilakukan dengan membandingkan antara dosis yang direncanakan TPS Eclipse ver. 11 dan dosis yang diukur pada target organ target dan organ beresiko menggunakan teknik IMRT dan VMAT. Hasilnya adalah deviasi dosis pada organ target menggunakan teknik IMRT dan VMAT adalah kurang dari 5%. Demikian pula, deviasi dosis pada bladder dan rectum untuk kedua teknik juga kurang dari 5% karena posisinya sangat dekat dengan target volume. Di sisi lain, deviasi dosis di femoral head lebih dari 5% untuk kedua teknik karena lokasinya pada gradien dosis rendah. Selanjutnya, deviasi dosis organ target untuk teknik IMRT cenderung lebih kecil dari teknik VMAT baik untuk TLD dan Film. Perbedaan dosis pada dosis titik organ target antara IMRT dan VMAT kurang dari 1% tetapi terjadi pada dosis yang random untuk organ beresiko. Adapun dosis permukaan pada teknik IMRT cenderung lebih kecil dari teknik VMAT jika kita menggunakan TLD, tetapi dosis pada film EBT2 cenderung sama antara teknik IMRT dan VMAT.

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Have been done the dose verification of the target and healthy tissues around by placing the TLD Rod LiF100 and EBT2 Gafchromic film at slab hole of pelvic part of the Alderson Rando phantom for prostate cancer simulation. The Exposed TLDs was evaluated using the TLD Reader Harshaw, while Gafchromic Film EBT2 was scanned using Epson Perfection V700 scanner with transmission mode, red channel and resolution 72 dpi. The point dose measurements were compared between planned dose TPS Eclipse ver. 11 and measured dose at target volume organ and organ at risk for IMRT and VMAT techniques. The result is the dose difference at target volume for IMRT and VMAT are less than 5%. Similarly, the dose difference at Bladder and Rectum for both techniques are also less than 5% due to the position of OAR is very close to target volume. On the other hand, the dose difference at Femoral head are more than 5% for both techniques because the location of OAR already in low gradient dose. Furthermore, the difference dose of the target volume for IMRT technique is tends to be smaller than VMAT either for TLD and film detectors. The dose difference at point dose of target volume between IMRT and VMAT techniqe are less than 1% but it occur in random number for organ at risk. More over, the surface dose of IMRT tend to be smaller than VMAT dose if we are using TLDs, but the dose of EBT2 films tend to be similar between IMRT and VMAT techniques."