Saeed Ahmad Buzdar, M. Afzal, Andrew Todd- Pokropek


Background: In radiotherapy treatment, the calculation of radiation dose distribution in target volume
lead to an optimum set of planning parameters. This worked has been aimed to compare two photon
beam dose calculation algorithms in the Oncentra Treatment Planning system for Varian Linear
Accelerator, to assure the quality of treatment planning. Methods: Monitor Units to be delivered on
normalization depth in patient has been calculated using the pencil beam and collapsed cone algorithms
for two photon energies 6 and 10 MV. The percentage depth dose and beam profiles for 21 treatment
fields, for both the calculation systems have been compared for both photon energies. Results: The
percentage depth doses and beam profiles for both calculation systems are comparable in large field
sizes as well as central axis field settings. The doses at normalization depth deviate for some field
settings, but in central axis large field sizes the difference in within tolerance limits. Conclusion: Both
calculation algorithms are in close agreement in most of the field settings (mainly in central axis fields),
within tolerance level. The difference is relatively greater in small field sizes and off-axis field settings.
Keywords: Radiotherapy, treatment planning, dose distribution, pencil beam, collapsed cone

Full Text:



Podgorsak EB. Radiation Oncology Physics: a handbook for

teachers and students. Vienna: IAEA; 2005.

Mohan R, Chui C, Lidofsky L. Differential pencil beam dose

computation model for photons calculations. Med Phys


Murray DC, Hoban PW, Metcalfe PE, Round WH. 3-D

superposition for radiotherapy treatment planning using fast

Fourier transforms. Aust Phys Eng Sci Med 1989;12:128–37.

Boyer AL, Zhu YP, Wang L, Francois P. Fast Fourier transform

convolution calculations of x-ray dose distributions in

homogeneous media. Med Phys 1989;16:248–53.

J Ayub Med Coll Abbottabad 2010;22(3)

Ahnesjo A, Collapsed cone convolution of radiant energy for

photon dose calculation in heterogeneous media. Med. Phys


Metcalfe PE, Hoban PW, Murray DC, Round WH. Beam

Hardening of 10 MV radiotherapy x-rays: Analysis using a

convolution/superposition method. Phys Med Biol


Traberg Hansen A, Petersen JB, Høyer M, Christensen JJ.

Comparison of two dose calculation methods applied to

extracranial stereotactic radiotherapy treatment planning.

Radiother Oncol 2005;77(1):96–8.

Nisbet A, Beange I, Vollmar HS, Irvine C, Morgan A, Thwaites

DI. Dosimetric verification of a commercial collapsed cone

algorithm in simulated clinical situations. Radiother Oncol


Hasenbalg F, Neuenschwander H, Mini R, Born EJ. Collapsed

cone convolution and analytical anisotropic algorithm dose

calculations compared to VMC++ Monte Carlo simulations in

clinical cases. Phys Med Biol 2007;52:3679–91.

Dobler B, Walter C, Knopf A, Fabri D, Loeschel R, Polednik M,

et al. Optimization of extracranial stereotactic radiation therapy

of small lung lesions using accurate dose calculation algorithms.

Radiat Oncol 2006;1:45.

Carlsson Tedgren A, Ahnesjo A, Optimization of the

computational efficiency of a 3D, collapsed cone dose calculation

algorithm for brachytherapy. Med Phys 2008;35:1611–8.

Treutwein M, Bogner L, Electron fields in clinical application. A

comparison of pencil beam and Monte Carlo algorithm.

Strahlenther Onkol 2007;183:454–8.


  • There are currently no refbacks.

Contact Number: +92-992-382571

email: [jamc] [@] []