Performance characteristics of the Pantak Therapax-150 superficial X-ray treatment machine: measurements and calculations

  • S. S. A. Natto


The beam and operating performance characteristics of a superficial X-ray unit, the Pantak Therapax-150 have been evaluated and benchmarked against the Monte Carlo code-MCNP. Parameters which were studied included beam quality, central axis depth dose and field uniformity for several applicator sizes and focal skin distances (FSDs) with the tube operating between 50 and 150 kVP accelerating potential. MCNP calculations were compared with five published qualities: 3.75 mm Al, 3.27 mm Al, 2.43 mm Al, 7.15 mm Al and 1.65 mm Cu half value layer (HVL). The unit has been found to provide beam characteristics similar to those reported for other superficial therapy machines. For most of the combinations of radiation qualities and applicators, good agreement between experiments and calculations was obtained. Calculated data when compared with other workers was not worse than 8.8%.

Key words

X-ray MCNP beam quality central axis depth dose field uniformity 


  1. 1.
    Klevenhagen, S. C., Aukett, R. J., Harrison, R. M., Moretti, C., Nahum, A. E. Rosser, K. E.The IPEMB code of practice for the determination of absorbed dose for x-rays below 300 kV generating potential (0.035 mm Al-4 mm Cu HVL; 10-300 kV generating potential), Physics in Medicine and Biology, 41 (12): 2605–2625, 1996.CrossRefGoogle Scholar
  2. 2.
    NCS,NCS protocol for dosimetry of low and medium energy x-rays. NCS Report 10, 1997.Google Scholar
  3. 3.
    Ma, C-M, Coffey, C. W., DeWerd, L. A., Liu, C., Nath, R., Seltzer, S. M., Seuntjens, J. P. (AAPM TG61)A protocol of kilovoltage x-ray beam dosimetry in radiotherapy and radiobiology, 1999.Google Scholar
  4. 4.
    Li, X. A., Ma, C-M, Salhani, D., Agboola, A.Dosimetric evaluation of a widely used kilovoltage x-ray unit for endocavitary radiotherapy, Medical Physics, 25 (8): 1464–1471., 1998.CrossRefPubMedGoogle Scholar
  5. 5.
    Birch, R., Marshall, M.Computation of Bremsstrahlung x-ray spectra and comparison with spectra measured with a Ge(Li) detector, Physics in Medicine and Biology, 24 (3): 505–517, 1979.CrossRefPubMedGoogle Scholar
  6. 6.
    Verhaegen, F., Nahum A. E., Van de Putte S. and Namito Y.Monte Carlo modelling of radiotherapy kV x-ray units, Physics in Medicine and Biology, 44 (7): 1767–1789, 1999.CrossRefPubMedGoogle Scholar
  7. 7.
    Briesmeister, J. F.MCNP-a general Monte Carlo code for neutron and photon transport, Los Alamos National Laboratory Report LA 7396-M, 1997.Google Scholar
  8. 8.
    Love, P. A., Lewis, D. G., Al-Affan, I. A. M., Smith, C. W.Comparison of EGS4 and MCNP Monte Carlo codes when calculating radiotherapy depth-doses, Physics in Medicine and Biology, 43 (5): 1351–1357, 1998.CrossRefPubMedGoogle Scholar
  9. 9.
    British Institute of Radiology and Hospital Physicists’ Association working party,Central Axis Depth Dose Data for use in Radiotherapy, Supplement 17 (The British Institute of Radiology, London), 1983.Google Scholar
  10. 10.
    Niroomand-Rad, A., Gillin, M. T., Lopez, F., Grimm, D. F.Performance characteristics of an orthovoltage X-ray therapy Machine, Medical Physics, 14 (5): 874–878, 1987.CrossRefPubMedGoogle Scholar
  11. 11.
    Gerig, L., Soubra, M., Salhani, D.Beam characteristics of the Therapax DXT300 orthovoltage therapy unit, Physics in Medicine and Biology, 39 (9): 1377–1392, 1994.CrossRefPubMedGoogle Scholar
  12. 12.
    Aukett, R. J., Thomas, W. D., Seaby, A. W., and Gittins, J. T.Performance characteristics of the Pantak DXT-300 kilovoltage X-ray treatment machine, British Journal of Radiology, 69 (8): 726–734, 1996.CrossRefPubMedGoogle Scholar
  13. 13.
    Lillicrap, S. C., Wilson, B. C., Edser, E., Stanley, D.A new superficial X-ray Therapy unit, British Journal of Radiology, 47 (555): 193–195, 1974.CrossRefPubMedGoogle Scholar
  14. 14.
    Scrimger, J. W., Connors, S. G.Performance characteristics of a widely used orthovoltage x-ray therapy unit, Medical Physics, 13 (2): 267–269, 1986.CrossRefPubMedGoogle Scholar
  15. 15.
    Kurup, R. G., Glasgow, G. P.Dosimetry of a kilovoltage radiotherapy x-ray machine, Medical Dosimetry, 8: 179, 1993.Google Scholar

Copyright information

© Australasian College of Physical Scientists and Engineers in Medicine 2002

Authors and Affiliations

  1. 1.Department of Physics Faculty of Applied SciencesUmm Al-Qura UniversityMakkahSaudi Arabia

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