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Total scatter factor for small fields in radiotherapy: a dosimetric comparison

Published online by Cambridge University Press:  27 November 2017

Qurat-ul-ain Shamsi ,
Saeed Ahmad Buzdar ,
Saima Altaf ,
Atia Atiq ,
Maria Atiq  and
Khalid Iqbal
Qurat-ul-ain Shamsi*
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Saeed Ahmad Buzdar
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Saima Altaf
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Atia Atiq
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Maria Atiq
Affiliation:
Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab, Pakistan
Khalid Iqbal
Affiliation:
Clinical & Radiation Oncology Department, Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Punjab, Pakistan
*
Correspondence to: Qurat-ul-ain Shamsi, Physics Department, The Islamia University of Bahawalpur, Bahawalpur, Punjab 63100, Pakistan. E-mail: annieshamsi@hotmail.com. Tel: +92622875063.
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Abstract

Purpose

Small field dosimetry is complicated and accuracy in the measurement of total scatter factor (TSF) is crucial for dosimetric calculations, in making optimum intensity-modulated radiotherapy plans for treating small target volumes. In this study, we intended to determine the TSF measuring properties of CC01 and CC04 detectors for field sizes ranging from sub-centimetre to the centimetre fields.

Material and methods

CC01 and CC04 chamber detectors were used to measure TSF for 6 and 18 MV photon beam delivered from the linear accelerator, through small fields in a water phantom. Small fields were created by collimator jaws and multi-leaf collimators separately, with field sizes ranging from 0·6 to 10 cm2 and 0·5 to 20 cm2, respectively.

Results

CC01 measured TSF at all the given field sizes created by jaws and multi-leaf collimators for both 6 and 18 MV beams whereas CC04 could not measure TSF for field sizes <1 cm2 due to volume averaging and perturbation effects.

Conclusion

CC01 was shown to be effective for measurement of TSF in sub-centimetre field sizes. CC01 can be employed to measure other dosimetric quantities in small fields using different energy beams.

Keywords

chamber detectors CC01 and CC04collimator jawslinear acceleratormulti-leaf collimatorssmall field dosimetry
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 17 , Issue 3 , September 2018 , pp. 292 - 296
Copyright
© Cambridge University Press 2017 

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