The Effect of ≤3 mm Geometric Errors on the Percentage Depth Dose (PDD) and Beam Profile (BP) Parameters in Relative Dose Measurements Taken in the Linear Accelerator Device (Linac)
Öz
The
modern linear accelerator (Linak) is a device that produces high-energy X-rays
and electron beams for the treatment of cancer patients. The basis of radiation
therapy is based on the interaction between substance and radiation. Therefore,
the interaction between radiation and matter transforms the science of radiation
physics into clinical treatment of cancer. In radiotherapy, the most basic
relative evaluations for dosimetric measurements are; It consists of a
percentage deep dose (DD%) which shows the variation of the X-ray depending on
the depth, and the beam profile (IP) measurements at which the flatness and
symmetry of the beam can be calculated at a certain depth. DD% is the ratio of
the radiation dose measured at a certain depth to the dose measured at the
maximum dose depth. In this study, it is aimed to investigate the effect of ≤ 3
mm geometric error that can be made in beam data measurements on DD% for
different field sizes and on IP parameters for different depths. In addition, the effect of geometric error on DD%
and IP parameters for different ion chambers
was investigated. The results show that the ≤3 mm geometric error during the
measurements has a significant effect especially on DD% parameters and small
field symmetry.
Anahtar Kelimeler
Linear accelerator Radiotherapy Percentage depth dose Beam profile
Kaynakça
- [1] J. Horton, Handbook of Radiation Therapy Physics, Englewood Cliffs, NJ: Prentice-Hall, 1987, pp. 200-1100.
- [2] M. Hossain, Y. Xiao, and M. S. Huq, “An investigation of a model of percentage depth dose for irregularly shaped fields,” International Journal of Cancer, 96, 140-145, 2001.
- [3] M. J. Price, K. R. Hogstrom, J. A. Antolak, A. White, D. Charles, and R. A. Boyd, “Calculating percent depth dose with the electron pencil-beam redefinition algorithm,” Journal of Applied Clinical Medical Physics, 2, 61-76, 2010.
- [4] K. Ślosarek, and A. Rembielak, “Comparison of Percent Depth Doses for Various Linear Accelerators,” Med. Physics, 11, 39–50, 2005.
- [5] T. G. Kutcher, L. Chair, M. Coia, W. F. Gillin, S. Hanson, R. J. Leibel, J. R. Morton, J. Palta, L. E. Purdy, G. K. Reinstein, M. Svensson, and L. Wingfield, “Comprehensive QA for Radiation Oncology,” Med. Phys., 21, 581-618, 1994.
- [6] C. Packard, “Calculation of percentage depth dose. Radiology,” Radiology Society of North America. 82nd scientific assembly and annual meeting, Chicago, Illiois. 2009, 130 (5): 44 – 48
- [7] IAEA (International Atomic Energy Agency), “Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water,” TRS-398, 11, 157-164, 2004.
- [8] I. J. Dasa, G. X. Ding, and A. Ahnesjö, “Small fields: Nonequilibrium radiation dosimetry,” Med. Phys. 35, 206-216, 2008.
- [9] E. Nahum, “Perturbation effects in dosimetry. Kilovoltage x-rays and electrons,” Phys. Med. Biol. 41,1531–1580, 1996.
- [10] A. Sauer, and J. Wilbert, “Measurement of output factors for small photon beams,” Med. Physics, 34,1983–1988, 2007.
- [11] R. N. Sruti, M. M. Islam, M. M. Rana, M. H. Bhuiyan, K. A. Khan, M. K. Newaz, and M. S. Ahmed, “Measurement of Percentage Depth Dose of a Linear Accelerator for 6 MV and 10 MV Photon Energies,” Nuclear Science and applications 24, 29-32, 2015.
- [12] IEC (International Electrotechnical Commission), “Medical electrical equipment-Medical electron accelarators-Functional performance characteristics,” 2007, Standard IEC-60976, IEC, Geneva.
- [13] M. J. Day and E. G. Aird, “Central Axis Depth Dose Data for Use in Radiotherapy,” BJR, Vol. Sup. 25, 90s, 1996.
- [14] American Association of Physicists in Medicine(AAPM), “Comprehensive Qa for Radiation Oncology,” 1994, Task Group 40, AAPM,USA.
- [15] C. Martens, D. Wagter, and W. Neve, “The value of the PinPoint ion chamber for characterization of small field segments used in intensity modulated radiotherapy,” Phys. Med. Biol. 45, 2519–2530, 2000.
- [16] S. G. Lu, Y. C. Ahn, S. J. Huh, and I. J. Yeo, “Film dosimetry for intensity modulated radiation therapy: Dosimetric evaluation,” Med. Phys. 29, 351–355, 2002.
- [17] L. Childress, L. Dong, and I. I. Rosen, “Rapid radiographic film calibration for IMRT verification using automated MLC fields,” Med. Phys. 29, 2384–2390, 2002.
- [18] V. Esch, J. Bohsung, P. Sorvari, M. Tenhunen, M. Paiusco, M. Lori, P. Engstrom, H. Nystrom, and D. P. Huyskens, “Acceptance tests and quality control (QC) procedures for the clinical implementation of intensity modulated radiotherapy (IMRT) using inverse planning and the sliding window technique: Experience from five radiotherapy departments,” Radiother. Oncol. 65, 53–70, 2002.
- [19] W. U. Laub, and T. Wong, “The volume effect of detectors in the dosimetry of small fields used in IMRT,” Med. Phys. 30, 341–347, 2003.
- [20] IEC (International Electrotechnical Commission), “Dosimeters With Ionization Chambers As Used in Radiotherapy,” Medical Electrical Equipment, 1997, Standard IEC-60731, IEC, Geneva.
- [21] F. M. Khan. The Physics of Radiation Therapy. New York: Springer 3rd ed.,2003, pp. 200-223,
- [22] S. K. Sahoo, A. K. Rath, R. N. Mukharjee, and B. Mallick “Commissioning of a Modern LINAC for Clinical Treatment and Material Research,” International Journal of Trends in Interdisciplinary Studies 1,10, 2012,
- [23] F. G. Vicente, J. M. Delgado, and M. Peraza, “Experimental determination of the convolution kernel for the study of the spatial response of a detector,” Med. Phys. 25, 202–207, 1998.
Lineer Hızlandırıcı Cihazında (Linak) Alınan Rölatif Doz Ölçümlerinde ≤ 3 mm Geometrik Hataların Yüzde Derin Doz (%DD) ve Işın Profil (IP) Parametreleri Üzerine Etkisi
Öz
Modern lineer
hızlandırıcı (Linak), kanserli hastaların tedavisi için yüksek enerjili X
ışınları ve elektron demetleri üreten bir cihazdır. Radyasyon tedavisinin
temeli madde ve radyasyon arasındaki etkileşime dayanır. Bu nedenle, radyasyon
ve madde arasındaki etkileşim, radyasyon fiziği bilimini kanserin klinik
tedavisine dönüştürür. Radyoterapide, dozimetrik ölçümler için en temel rölatif
değerlendirmeler; X- ışınının derinliğe bağlı olarak değişimi gösteren yüzde
derin doz (%DD) ve belli bir derinlikte ışının düzgünlüğünü ve simetrisini
gösteren ışın profil (IP) ölçümlerden oluşmaktadır. %DD, belli bir derinlikte
ölçülen radyasyon dozunun, maksimum doz derinliğinde ölçülen doza bölünmesiyle
hesaplanır. Bu çalışmada, lineer hızlandırıcıda hasta öncesi başlangıç
ölçümlerinde yapılabilecek ≤ 3 mm geometrik hatanın farklı alan boyutları için
%DD ve farklı derinlikteki IP parametreleri üzerindeki etkisini görmek
amaçlanmıştır. Ayrıca yapılabilecek geometrik hatanın iyon odası farkına göre
değişimi araştırılmıştır. Sonuçlar, ölçümler sırasında yapılabilecek ≤3 mm
geometrik hatanın, özellikle yüzde derin doz parametreleri ve küçük alan
simetrisi üzerinde etkisinin oldukça fazla olduğunu göstermektedir.
Anahtar Kelimeler
Kaynakça
- [1] J. Horton, Handbook of Radiation Therapy Physics, Englewood Cliffs, NJ: Prentice-Hall, 1987, pp. 200-1100.
- [2] M. Hossain, Y. Xiao, and M. S. Huq, “An investigation of a model of percentage depth dose for irregularly shaped fields,” International Journal of Cancer, 96, 140-145, 2001.
- [3] M. J. Price, K. R. Hogstrom, J. A. Antolak, A. White, D. Charles, and R. A. Boyd, “Calculating percent depth dose with the electron pencil-beam redefinition algorithm,” Journal of Applied Clinical Medical Physics, 2, 61-76, 2010.
- [4] K. Ślosarek, and A. Rembielak, “Comparison of Percent Depth Doses for Various Linear Accelerators,” Med. Physics, 11, 39–50, 2005.
- [5] T. G. Kutcher, L. Chair, M. Coia, W. F. Gillin, S. Hanson, R. J. Leibel, J. R. Morton, J. Palta, L. E. Purdy, G. K. Reinstein, M. Svensson, and L. Wingfield, “Comprehensive QA for Radiation Oncology,” Med. Phys., 21, 581-618, 1994.
- [6] C. Packard, “Calculation of percentage depth dose. Radiology,” Radiology Society of North America. 82nd scientific assembly and annual meeting, Chicago, Illiois. 2009, 130 (5): 44 – 48
- [7] IAEA (International Atomic Energy Agency), “Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water,” TRS-398, 11, 157-164, 2004.
- [8] I. J. Dasa, G. X. Ding, and A. Ahnesjö, “Small fields: Nonequilibrium radiation dosimetry,” Med. Phys. 35, 206-216, 2008.
- [9] E. Nahum, “Perturbation effects in dosimetry. Kilovoltage x-rays and electrons,” Phys. Med. Biol. 41,1531–1580, 1996.
- [10] A. Sauer, and J. Wilbert, “Measurement of output factors for small photon beams,” Med. Physics, 34,1983–1988, 2007.
- [11] R. N. Sruti, M. M. Islam, M. M. Rana, M. H. Bhuiyan, K. A. Khan, M. K. Newaz, and M. S. Ahmed, “Measurement of Percentage Depth Dose of a Linear Accelerator for 6 MV and 10 MV Photon Energies,” Nuclear Science and applications 24, 29-32, 2015.
- [12] IEC (International Electrotechnical Commission), “Medical electrical equipment-Medical electron accelarators-Functional performance characteristics,” 2007, Standard IEC-60976, IEC, Geneva.
- [13] M. J. Day and E. G. Aird, “Central Axis Depth Dose Data for Use in Radiotherapy,” BJR, Vol. Sup. 25, 90s, 1996.
- [14] American Association of Physicists in Medicine(AAPM), “Comprehensive Qa for Radiation Oncology,” 1994, Task Group 40, AAPM,USA.
- [15] C. Martens, D. Wagter, and W. Neve, “The value of the PinPoint ion chamber for characterization of small field segments used in intensity modulated radiotherapy,” Phys. Med. Biol. 45, 2519–2530, 2000.
- [16] S. G. Lu, Y. C. Ahn, S. J. Huh, and I. J. Yeo, “Film dosimetry for intensity modulated radiation therapy: Dosimetric evaluation,” Med. Phys. 29, 351–355, 2002.
- [17] L. Childress, L. Dong, and I. I. Rosen, “Rapid radiographic film calibration for IMRT verification using automated MLC fields,” Med. Phys. 29, 2384–2390, 2002.
- [18] V. Esch, J. Bohsung, P. Sorvari, M. Tenhunen, M. Paiusco, M. Lori, P. Engstrom, H. Nystrom, and D. P. Huyskens, “Acceptance tests and quality control (QC) procedures for the clinical implementation of intensity modulated radiotherapy (IMRT) using inverse planning and the sliding window technique: Experience from five radiotherapy departments,” Radiother. Oncol. 65, 53–70, 2002.
- [19] W. U. Laub, and T. Wong, “The volume effect of detectors in the dosimetry of small fields used in IMRT,” Med. Phys. 30, 341–347, 2003.
- [20] IEC (International Electrotechnical Commission), “Dosimeters With Ionization Chambers As Used in Radiotherapy,” Medical Electrical Equipment, 1997, Standard IEC-60731, IEC, Geneva.
- [21] F. M. Khan. The Physics of Radiation Therapy. New York: Springer 3rd ed.,2003, pp. 200-223,
- [22] S. K. Sahoo, A. K. Rath, R. N. Mukharjee, and B. Mallick “Commissioning of a Modern LINAC for Clinical Treatment and Material Research,” International Journal of Trends in Interdisciplinary Studies 1,10, 2012,
- [23] F. G. Vicente, J. M. Delgado, and M. Peraza, “Experimental determination of the convolution kernel for the study of the spatial response of a detector,” Med. Phys. 25, 202–207, 1998.
Ayrıntılar
| Birincil Dil | Türkçe |
|---|---|
| Konular | Metroloji,Uygulamalı ve Endüstriyel Fizik |
| Bölüm | Makaleler |
| Yazarlar | |
| Yayımlanma Tarihi | 30 Kasım 2019 |
| Yayımlandığı Sayı | Yıl 2019 Cilt: 14 Sayı: 2 |
