Sains Malaysiana 36(1): 59-63 (2007)

The 12 MeV Electron Beam Reference Depth versus

Field Size for Two IAEA Protocols

(Kedalaman Rujukan Alur Elektron 12 MeV Melawan

Saiz Medan untuk Dua Protocol IAEA)

S. B. Samat & S. Siaw

School of Applied Physics

Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor, Malaysia

ABSTRACT

The 12 MeV electron beam reference depth z_ref  at three field size FS 10 × 10 cm², 15 × 15 cm², 20 × 20 cm² were determined for TRS277 and TRS398 IAEA protocols. At a fixed SSD = 100 cm, results showed that all z_ref TRS398 are higher than z_ref TRS277, in the range of 0.01 to 0.10 cm. Reasons for this is explained. For a particular z_ref of TRS398 at FS 10 × 10 cm², comparison was made with earlier results obtained by other worker that used similar experimental set-up except a different linear accelerator. The present result is comparable since it is higher only by 0.11cm.

Keywords: Reference depth; field sizes; TRS277; TRS398; 12 MeV electron beam

ABSTRAK

Kedalaman rujukan z_ref  untuk alur elektron 12 MeV pada tiga saiz medan FS 10 × 10 cm², 15 × 1 5cm², 20 × 20 cm² ditentukan bagi protokol IAEA TRS277 and TRS398. Pada satu ketetapan SSD=100 cm, keputusan menunjukkan kesemua z_ref TRS398 lebih tinggi dari z_ref TRS277, dalam julat 0.01 to 0.10 cm. Sebab untuk ini dijelaskan. Untuk satu z_ref  TRS398 tertentu pada FS 10 × 10 cm², perbandingan dibuat  dengan keputusan terdahulu yang diperolehi oleh pekerja lain, yang susunan ujikajinya sama kecuali pemecut linear  yang digunakan berlainan. Keputusan kerja ini didapati setara kerana ia hanya lebih tinggi sebanyak 0.11cm.

Kata kunci: Kedalaman rujukan; saiz medan; TRS277; TRS398; 12 MeV alur elektron

RUJUKAN/REFERENCES

IAEA 1997. Absorbed dose determination in photon and electron beams: An international code of practice for dosimetry based on standards of air kerma, TRS-277. 2nd edition. Vienna: International Atomic Energy Agency.

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.Palmans, H., Nafaa, L., de Patoul, N., Denis, J.M., Tomsej, M. & Vynckier, S. 2003. A dosimetry study comparing NCS report-5, IAEA TRS-381, AAPM TG-51 and IAEA TRS-398 in three clinical electron beam energies. Phys. Med. Biol. 48: 1091-1107.

Palmans, H. Nafaa, L., de Patoul, N. Denis, J.M., Tomsej, M. & Vynckier, S. 2003.  A dosimetry study comparing NCS report-5, IAEA TRS-381, AAPM TG-51 and IAEA TRS-398 in three clinical electron beam energies. Phys. Med. Biol. 48: 1091-1107.