A New TLD Holder for External Radiotherapy Beam Audit


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Yaşar D., Demir B., Kam E. , Karahan G., Okutan M.

SDU Journal of Science, cilt.8, sa.1, ss.92-99, 2013 (Hakemli Üniversite Dergisi)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 8 Konu: 1
  • Basım Tarihi: 2013
  • Dergi Adı: SDU Journal of Science
  • Sayfa Sayıları: ss.92-99

Özet

In present study, a special TLD holder inserted to a solid water phantom for TLD irradiation was designed and results were compared with the TLD results irradiated in a plastic bucked using
International Atomic Energy Agency (IAEA), standard TLD holder as recommended by IAEA. Powder TLD-100 was used in the study and the capsules filling powder TLD were irradiated using Co-60 beams in RW3 type solid phantom with new holder. The absorbed dose measurements for TLD were performed by Harshaw 4500 model TLD reader and the results were confirmed using a 0.6 cc ionization chamber in RW3 plastic phantom. For different irradiation setup, the closest dose values to the prescribed dose of 2 Gy were only obtained with using the new TLD holder (2.022+ 0.017cGy) with lowest error value. The average and standard deviation for standard IAEA water phantom and plastic bucked set-up were 2.014+0.024 cGy and 1.948+0.062cGy respectively. While the maximum average absolute difference (%3.5) and the maximum % error (%3.16) were found in the hospital condition with bucket filled with water, the minimum average absolute difference and the minimum % error were %1.32 and %0.86 respectively, with our new TLD holder in the solid water phantom . In our opinion, the reason of this good consistency is the reproducibility of TLD position that created by means of our TLD holder. This study shows that non-standard conditions may cause important differences between SSDL (Secondary Standard Dosimetry Laboratory) and hospital dose results.