Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2018, Vol. 29 ›› Issue (5): 66 doi: 10.1007/s41365-018-0404-2


Variation in patient dose due to differences in calibration and dosimetry protocols

Wazir Muhammad 1,2 • Asad Ullah 2 • Gulzar Khan 3 • Tahir Zeb Khan 3 • Tauseef Jamaal 4 • Fawad Ullah 5 • Matiullah Khan 5 • Amjad Hussain 6   

  1. 1 Department of Therapeutic Radiology, Yale-School of Medicine, Yale University, New Haven, CT 06520-8040, USA
    2 Heath Physics Division (HPD), Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad 45650, Pakistan
    3 Department of Physics, Abul Wali Khan University, Mardan 23200, Pakistan
    4 Pakistan Institute Nuclear Science & Technology (PIEAS), Islamabad 45650, Pakistan
    5 Department of Physics, Kohat University of Science and Technology, Kohat 26000, Pakistan
    6 Department of Medical Physics, CancerCare Manitoba, Brandon, MB R7A 2B3, Canada
  • Contact: Wazir Muhammad;
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Wazir Muhammad, Asad Ullah, Gulzar Khan, Tahir Zeb Khan, Tauseef Jamaal, Fawad Ullah, Matiullah Khan, Amjad Hussain. Variation in patient dose due to differences in calibration and dosimetry protocols.Nuclear Science and Techniques, 2018, 29(5): 66     doi: 10.1007/s41365-018-0404-2


For precise and accurate patient dose delivery, the dosimetry system must be calibrated properly according to the recommendations of standard dosimetry protocols such as TG-51 and TRS-398. However, the dosimetry protocol followed by a calibration laboratory is usually different from the protocols that are followed by different clinics, which may result in variations in the patient dose. Our prime objective in this study was to investigate the effect of the two protocols on dosimetry measurements. Dose measurements were performed for a Co-60 teletherapy unit and a high-energy Varian linear accelerator with 6 and 15 MV photon and 6, 9, 12, and 15 MeV electron beams, following the recommendations and procedures of the AAPM TG-51 and IAEA TRS-398 dosimetry protocols. The dosimetry systems used for this study were calibrated in a Co-60 radiation beam at the Secondary Standard Dosimetry Laboratory (SSDL) PINSTECH, Pakistan, following the IAEA TRS-398 protocol. The ratio of the measured absorbed doses to water in clinical setting, Dw (TG-51/TRS-398), was 0.999 and 0.997 for 6 and 15 MV photon beams, whereas these ratios were 1.013, 1.009, 1.003, and 1.000 for 6, 9, 12, and 15 MeV electron beams, respectively. This difference in the absorbed dosesto- water Dw ratio may be attributed mainly due to beam quality (KQ) and ion recombination correction factor.

Key words: Radiation dosimetry, Dosimetry systems calibrations, Patient dose, Absorbed dose-to-water ratio, AAPM TG-51, IAEA TRS-398