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Dosimetric determination of tissue maximum ratios in small fields

Published online by Cambridge University Press:  06 April 2018

Qurat-ul-ain Shamsi ,
Saeed Ahmad Buzdar ,
Atia Atiq ,
Maria Atiq ,
Saima Altaf  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
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
Saima Altaf
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
*
Author for correspondence: Qurat-ul-ain Shamsi, Physics Department, The Islamia University of Bahawalpur, Bahawalpur 63100, Punjab, Pakistan. Tel: +92622875063;E-mail: [email protected]
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Abstract

Aims

This exploration is intended to measure tissue maximum ratios (TMRs) in smaller fields through CC01 detector and to compare CC01 measured TMRs with Pinnacle treatment planning software (TPS) calculated TMRs.

Materials and methods

CC01 compact chamber detector was used to measure TMR in water phantom for 6 and 18 MV beam delivered from Varian linear accelerator. Pinnacle TPS was employed in this study to calculate TMR from the measured percentage depth doses data. CC01 measured TMR data was compared with the calculated TMR data at depths from 5 to 20 cm for field sizes varying from 1 to 10 cm2.

Results

For the smallest given field size of 1 cm2, CCO1 measured 13·95% higher TMR value for 18 MV beam than that for 6 MV beam. At 20 cm depth for 1 cm2 field size, TMR due to 18 MV beam was 52·4% higher than the TMR due to 6 MV beam. For 6 MV beam, the maximum difference appeared between the measured TMR and pinnacle calculated TMR was 2·8% and for 18 MV beam, the maximum difference was 4%.

Conclusion

For both 6 and 18 MV beam, there was good agreement between CC01 measured and Pinnacle calculated TMRs for the field sizes ranging from 1 to 10 cm2. This exploration can be extended to the determination of other dosimetric parameters like TARs, TPRs in small fields.

Keywords

6 and 18 MV photon beamcompact chamber detector CC01Pinnacle treatment planning softwaresmall field dosimetrytissue maximum ratios
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 17 , Issue 3 , September 2018 , pp. 289 - 291
Copyright
© Cambridge University Press 2018 

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References

1. Lu, T X, Han, F, Zhao, C et al. Experiences of intensity modulated radiation therapy (IMRT) for head and neck tumors. Ai Zheng 2001; 20 (10): 1095–1099.Google Scholar
2. Narayanasami, G, Cruz, W, Papanikolaou, N, Stakathis, S. Comparison between measured tissue phantom ratio values and calculated from percent depth doses with and without peak scatter correction factor in a 6 MV beam. Int. J Cancer Ther Oncol 2015; 3 (2): 1–5.Google Scholar
3. Aspradakis, M M, Byrne, J P, Palmans, H et al. IPEM Report 103: Small field MV photon dosimetry. No. IAEA-CN—182, INIS Volume 42, 1st edition. Vienna, Austria: Institute of Physics and Engineering in Medicine, 2010.Google Scholar
4. Das, I J, Ding, G X, Ahnesjö, A. Small fields: Nonequilibrium radiation dosimetry. Med Phys. 2008; 35: 206–215.Google Scholar
5. Scott, A J, Nahum, A E, Fenwick, J D. Using a Monte Carlo model to predict dosimetric properties of small radiotherapy photon fields. Med Phys. 2008; 35: 4671–4684.Google Scholar
6. Shamsi, Q, Buzdar, S A, Altaf, S, Atia, A, Atiq, M, Iqbal, K. Total scatter factor for small fields in radiotherapy: A dosimetric comparison. J Radiother Pract 2017; 16 (4): 444–450.Google Scholar
7. Das, I J, Morales, J, Francescon, P. Small field dosimetry: What have we learnt? In: Guerda Massillon JL et al. (eds). AIP Conference Proceedings, Volume 1747. No. 1. College park, MD: AIP Publishing, 2016.Google Scholar
8. Würfel, J U. Dose measurements in small fields. Med Phys 2013; 1 (1): 81–90.Google Scholar
9. Chen, L, Chen, L X, Sun, H Q et al. Measurements and comparisons for data of small beams of linear accelerators. Chin J Cancer 2009; 28 (3): 272–276.Google Scholar
10. Rahman, M A, Alam, M J, Akhtaruzzaman, M. Characteristics analysis of high energy external radiotherapy beams in water. Malay J Med Biol Res 2016; 3 (1): 51–60.Google Scholar
11. Bjärngard, B E, Bar-Deroma, R, Corrao, A. A survey of methods to calculate monitor settings. Int J Radiat Oncol Biol Phys 1994; 28: 749–752.Google Scholar
12. Ding, G X, Krauss, R. An empirical formula to obtain tissue-phantom ratios from percentage depth-dose curves for small fields. Phys Med Biol 2013; 58: 4781–4789.Google Scholar
13. Sharma, S D, Kumar, S, Dagaonkar, S S et al. Dosimetric comparison of linear accelerator-based stereotactic radiosurgery systems. J Med Phys 2007; 32 (1): 18–23.Google Scholar
14. Podgorsak, E B. Radiation Oncology Physics: A Handbook for Teachers and Students. Vienna: International Atomic Energy Agency, 2005.Google Scholar
15. Mesbahi, A. Dosimetric characteristics of unflattened 6MV photon beams of a clinical linear accelerator: A Monte Carlo study. Appl Radiat Isot 2007; 65: 1029–1036.Google Scholar
16. Pichandi, A, Kadirampatti, M G, Jerin, A, Balaji, K, Kilara, G. Analysis of physical parameters and determination of inflection point for Flattening Filter Free beams in medical linear accelerator. Rep Pract Oncol Radiother 2014; 19: 322–331.Google Scholar
17. Khan, F M, Gibbons, J P. Khan’s the Physics of Radiation Therapy. Philadelphia, PA: Lippincott Williams & Wilkins, 2014.Google Scholar
18. Jayaraman, S, Lanzl, L H. Basic ratios and factors for the dosimetry of external beam. Clin Radiother Phys 2004; 189–229.Google Scholar
19. British Journal of Radiology. Central axis depth dose data for use in radiotherapy. Br J Radiol Suppl 1983; 17: 1–147.Google Scholar
20. LaRiviere, P D. The quality of high-energy X-ray beams. Br J Radiol 1989; 62 (737): 473–481.Google Scholar
21. Osei, J E. Validation of calculated tissue maximum ratio (TMR) obtained from measured percentage depth dose (PPD) data for high energy photon beam (6 MV and 15 MV). Thesis work at Department of Medical Physics School of Nuclear and Allied Sciences, University of Ghana, 2015.Google Scholar
22. ICRU. Determination of Absorbed Dose in a Patient Irradiated by Beams of X- or Gamma-Rays in Radiotherapy Procedures. Bethesda, MD: International-Commission on Radiation Units and Measurement, 1976; ICRU Rep. 24.Google Scholar
23. Johansson, K A, Hariot, J C, Van Dam, J, Lepinoy, D, Setenac, I, Sernbo, G. Quality assurance control in the EORTC cooperative group of radiotherapy. 2. Dosimetric intercomposition. Radiather Oncol 1986; 7: 269–279.Google Scholar