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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: [email protected]. 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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References

1. Chaudhari, S H, Dobhal, R, Kinhikar, R A, Kadam, S S, Deshpande, D D. Measurement of total scatter factor for stereotactic cones with plastic scintillation detector. J Med Phys 2017; 42 (1): 9–13.Google Scholar
2. Sharma, S D. Challenges of small photon field dosimetry are still challenging. J Med Phys 2014; 39 (3): 131.Google Scholar
3. Das, I J, Ding, G X, Ahnesjö, A. Small fields: nonequilibrium radiation dosimetry. Med Phys 2008; 35: 206–215.Google Scholar
4. Aspradakis, M, Byrne, J, Palmans, H et al Small field MV photon dosimetry. IPEM Report No. 103. York, UK: Institute of Physics and Engineering in Medicine, 2010.Google Scholar
5. Das, IJ, Morales, J, Francescon, P. Small field dosimetry: What have we learnt? In Massillon-JL G, Fossion R, Mendez IM, Avila-Rodriguez MA, López-Pérez DO (eds). AIP Conference Proceedings, Volume 1747, No. 1. Indianapolis, IN, USA: AIP Publishing, 2016: 060001.Google Scholar
6. Francescon, P, Cora, S, Cavedon, C, Scalchi, P, Stancanello, J. CyberKnife dosimetric beam characteristics: comparison between experimental results and Monte Carlo simulation Robot. Radiosurgery 2005; 1 (1): 71–80.Google Scholar
7. Francescon, P, Kilby, W, Satariano, N. Monte Carlo simulated correction factors for output factor measurement with the CyberKnife system? Results for new detectors and correction factor dependence on measurement distance and detector orientation. Phys Med Biol 2014; 59: N11–N17.Google Scholar
8. Alfonso, R, Andreo, P, Capote, R et al. A new formalism for reference dosimetry of small and nonstandard fields. Med Phys 2008; 35 (11): 5179–5186.Google Scholar
9. Cranmer-Sargison, G, Weston, S, Evans, J A, Sidhu, N P, Thwaites, D I. Implementing a newly proposed Monte Carlo based small field dosimetry formalism for a comprehensive set of diode detectors. Med Phys 2011; 38: 6592–6602.Google Scholar
10. Azimi, R, Alaei, P, Higgins, P. The effect of small field output factor measurements on IMRT dosimetry. Med Phys 2012; 39 (8): 4691–4694.Google Scholar
11. Birgani, M J, Chegeni, H, Behrooz, M A, Bagheri, M, Danyaei, A, Shamsi, A. An analytical method to calculate phantom scatter factor for photon beam accelerators. Electron Physician 9 (1): 3523–3528.Google Scholar
12. Nasir, M K, Amjad, N, Razzaq, A, Siddique, T. Measurement and analysis of PDDs profile and output factors for small field sizes by CC13 and micro-chamber CC01. Int J Med Phys Clin Eng Radiat Oncol 2017; 6 (01): 36.Google Scholar
13. Podgorsak, E B. Radiation Oncology Physics: A Handbook for Teachers and Students. Vienna: International Atomic Energy Agency, 2005.Google Scholar
14. Khan, F M, John, P G. Khan’s the Physics of Radiation Therapy. Philadelphia, PA: Lippincott Williams & Wilkins, 2014.Google Scholar
15. Arnfield, M R, Siebers, J V, Kim, J O, Wu, Q, Keall, P J, Mohan, R. A method for determining multileaf collimator transmission and scatter for dynamic intensity modulated radiotherapy. Med Phys 2000; 27 (10): 2231–2241.Google Scholar
16. Jabbari, K, Akbari, M, Tavakoli, M B, Amouheidari, A. Dosimetry and evaluating the effect of treatment parameters on the leakage of multi leaf collimators in ONCOR linear accelerators. Adv Biomed Res 2016; 5 (1): 193–200.Google Scholar
17. Würfel, J U. Dose measurements in small fields. Med Phys 2013; 1 (1): 81–90.Google Scholar
18. Godson, H F, Ravikumar, M, Sathiyan, S, Ganesh, K M, Ponmalar, Y R, Varatharaj, C. Analysis of small field percent depth dose and profiles: comparison of measurements with various detectors and effects of detector orientation with different jaw settings. J Med Phys 2016; 41 (1): 12.Google Scholar
19. Apipunyasopon, L, Srisatit, S, Phaisangittisakul, N. An investigation of the depth dose in the build-up region, and surface dose for a 6-MV therapeutic photon beam: Monte Carlo simulation and measurements. J Radiat Res 2013; 54: 374–382.Google Scholar
20. Tyler, M K, Liu, P Z, Lee, C, McKenzie, D R, Suchowerska, N. Small field detector correction factors: effects of the flattening filter for Elekta and Varian linear accelerators. J Appl Clin Med Phys 2016; 17 (3): 223–235.Google Scholar
21. Azangwe, G, Grochowska, P, Georg, D et al. Detector to detector corrections: a comprehensive experimental study of detector specific correction factors for beam output measurements for small radiotherapy beams. Med Phys 2014; 41 (7): 072103.Google Scholar
22. Reduan, Aa, Mazurawati, Mb, Nur Iziana, Ma, Nik Ruzman, NIb, Ahmad, Za, Ahmad Lutfi, Yb. Verification of relative output factor (ROF) measurement for radiosurgery small photon beams. Health Environ J 2016; 7 (2): 20–31.Google Scholar
23. Washington, C M, Dennis, T. Leaver. Principles and Practice of Radiation Therapy. Amsterdam: Elsevier Health Sciences, 2015: 483–484.Google Scholar
24. Arnfield, M R, Siebers, J V, Kim, J O, Wu, Q, Keall, P J, Mohan, R. A method for determining multileaf collimator transmission and scatter for dynamic intensity modulated radiotherapy. Med Phys 2000; 27 (10): 2231–2241.Google Scholar