Sains Malaysiana 38(2): 203-207(2009)

 

Variation Of Beam Quality Correction Factor With Time: Cases For Ne2571 And Ne2581 Chambers In The 6 And 10 Mv X-Rays Beams

 (Perubahan Faktor Pembetulan Kualiti Dengan Masa: Kes Untuk Kebuk

Ne 2571 Dan Ne 2581 Dalam Alur Sinar-X 6 Dan 10 Mv)

 

 

S. B. Samat and S. X. Too

School of Applied Physics, Universiti Kebangsaan Malaysia (UKM)

43600 UKM Bangi, Selangor, Malaysia

 

T. Kadni and M.T. Dolah

Secondary Standard Dosimetry Laboratory (SSDL)

Malaysian Nuclear Agency (Nuclear Malaysia), 43000 Kajang, Selangor

Malaysia

 

Received:    4 June 2008 / Accepted:   30 July 2008

 

 

ABSTRACT

 

The values of beam quality correction factor kQ that were experimentally determined from year 2002 to 2008 were analysed. As kQ is the function of ionization chamber and beam quality, the analysis were based on three cases namely (a)  kQ(NE2571, 6 MV x-rays) that were determined from 17 measurements in the duration of 69 months at 6 radiotherapy centres, (b) kQ(NE2571, 10 MV x-rays) from 7 measurements in the duration of 12 months at one radiotherapy centre,  and (c) kQ(NE2581, 6 MV x-rays) from 5 measurements in the duration of 5 months also at one radiotherapy centre.   The purpose is to examine, in each case,  the variation kQ for all the measurements. In other words, to see variation kQ with time. Results obtained are 0.993(NE2571, 6 MV),  0.986(NE2571, 10 MV) and 0.986(NE2581, 6 MV).   This shows that in each case, despite the difference in the experimental data in getting kQ for all measurement, kQ remains constant with time. Reasons for this are explained. 

 

Keywords: variation of kQ; ionization chamber; NE2571;  NE2581; 6 MV x-rays; 10 MV x-rays

 

ABSTRAK

 

Nilai faktor pembetulan kualiti kQ yang ditentukan secara eksperimen dari tahun 2002 hingga 2008 dianalisis. Disebabkan kQ adalah fungsi kepada kebuk pengionan dan kualiti alur, analisis dijalankan berdasarkan tiga kes berikut: (a)  kQ(NE2571, sinar-x 6 MV) yang ditentukan dari 17 pengukuran dalam tempoh 69 bulan di 6 pusat radioterapi, (b) kQ(NE2571, sinar-x 10 MV) dari 7 pengukuran dalam tempoh 12 bulan di satu pusat radioterapi, dan (c) kQ(NE2581, sinar-x 6 MV) dari 5 pengukuran dalam tempoh 5 bulan juga di satu pusat radioterapi. Tujuan adalah untuk memeriksa, dalam setiap kes, perubahan bagi kQ untuk semua pengukuran. Dengan perkatan lain, untuk melihat perubahan kQ dengan masa. Keputusan yang diperoleh ialah 0.993(NE2571, 6 MV),  0.986(NE2571, 10 MV) dan 0.986(NE2581, 6 MV).   Ini menunjukkan dalam setiap kes, walaupun perbezaan dalam data eksperimen kQ bagi semua pengukuran, kQ tetap mempunyai nilai malar dengan masa. Sebab untuk ini dijelaskan. 

 

Kata kunci: perubahan; kQ; kebuk pengionan; NE 2571; NE 2581; sinar-x 6 MV; sinar-x 10MV

 

REFERENCE

 

Abdul Rani, E.M. 2005. Absorbed Dose To Water Values In A 6 MV X-Ray Beam Determined By Two IAEA Protocols: Comparison Of Accuracy And Precision. Msc Thesis, School Of Applied Physics, 185 Pages.

Amat, A. 2007. Comparison Of Accuracy And Precision Of Absorbed Dose To Water Values Determined By IAEA TRS-398 And AAPM TG-51 Protocols In A 6 MV X-Ray Beam. Msc Thesis, School Of Applied Physics, Universiti Kebangsaan Malaysia, 182 Pages.

IAEA. 2000. Absorbed Dose Determination In External Beam Radiotherapy: An International Code Of Practice For Dosimetry Based On Standards Of Absorbed Dose To Water, TRS-398. Vienna: International Atomic Energy Agency: 68.

Ibrahim, I. 2005. Absorbed Dose To Water Determined By Two IAEA Protocols TRS-277 and TRS-398 At X-Ray Beam Of 10 MV: Comparison Of Accuracy And Precision. Msc Thesis, School Of Applied Physics, Universiti Kebangsaan Malaysia,  147 Pages.

Pan, L.L. 2005. Comparison Of Accuracy and Precision Of Absorbed Dose To Water Values In a 10 MV X-Ray Beam Determined By IAEA TRS-398 And AAPM TG-51 Protocols. Msc Thesis, School Of Applied Physics, Universiti Kebangsaan Malaysia.

 

 

 
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