Comparison of Dose Distribution Effects for Various Bolus Materials in Electron Conformal Radiotherapy

Year 2020, Volume: 16 Issue: 2, 201 - 205, 24.06.2020

Serhat Aras , İhsan Oguz Tanzer , Türkan İkizceli

Abstract

In this study, the effects of various bolus materials on dose distributions were compared in electron conformal radiotherapy (ECRT). Superflab, Super Stuff pink wax and Paraffin wax bolus materials are used with 15MeV electron energy for dosimetric comparison. Additionally, 10 mm thick Super Stuff pink wax bolus and paraffin wax bolus materials were placed on the right eyelid of a patient. Using electron dose calculation algorithm and ion chamber measurements, dosimetric comparisons were made in the Eclipse treatment planning system (TPS). Both for measured and calculated dose, values were acquired 3 times and averaged for each case. Resulting differences are expressed as percentage differences. Dose differences were obtained in measurements with and without using bolus at several locations of the solid phantom, performed by the Roos Ion chamber. Dosimetric differences of 7-7.5% for Superflab, 10-10.5% for paraffin bolus and 13-14% for Super Stuff pink wax bolus are obtained. Besides, when dosimetric comparisons are made in the treatment planning system for cases with and without bolus; Dose differences were calculated to be 2-2.5% for superflab silicon bolus, 3-3.5% for paraffin wax bolus and 5-6% for Super Stuff pink wax bolus. To increase skin dose in curved anatomical structures in radiotherapy, it is safe to use the paraffin wax bolus material in radiotherapy clinic, as an alternative to Superflab silicon bolus and Super Stuff pink wax bolus materials, due to its low cost and ease of conforming to body surface contours.

Keywords

Radiotherapy, Superflab, Paraffin, Super Stuff

References

• [1]. Chang F, Chang P, Share F. Study of elasto-gel pads used as surface bolus material in high energy photon and electron therapy. International Journal of Radiation Oncology Biology Physics, 1992;22: 191-93.
• [2]. Vyas V, Palmer L, Mudge R, Jiang R, Fleck A. On bolus for megavoltage photon and electron radiation therapy. Med Dosim. 2013;38: 268–73.
• [3]. Fujimoto K, Shiinoki T, Yuasa Y, Hanazawa H, Shibuya K. Efficacy of patient-specific bolus created using three-dimensional printing technique in photon radiotherapy. Phys Med. 2017;38: 1-9.
• [4]. Ricotti R, Ciardo D, Pansini F, Bazani A, Comi S, Spoto R et al. Dosimetric characterization of 3D printed bolus at different infill percentage for external photon beam radiotherapy. Phys Med. 2017;39: 25-32.
• [5]. Banaee N, Nedaie H.A, Nosrati H, Nabavi M, Naderi M. Dose measurement of different bolus materials on surface dose. Journal of Radioprotection Research, 2013; 1(1): 10-3.
• [6]. Malaescu I, Marin C.N, Spunei M. Comparative study on the surface dose of some bolus materials. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 2015; 4:348-52.
• [7]. Burleson S, Baker J, Hsia A.T, Zhigang X. Use of 3D printers to create a patient‐specific 3D bolus for external beam therapy. Journal of Applied Clinical Medical Physics, 2015;16(3):166-178.
• [8]. Court LE, Tishler RB, Allen AM. Experimental evaluation of the accuracy of skin dose calculation for a commercial treatment planning system. Journal of Applied Clinical Medical Physics 2008; 9(1):29-35.
• [9]. Kong M, Holloway L. An investigation of central axis depth dose distribution perturbation due to an air gap between patient and bolus for electron beams. Australas Phys Eng Sci Med. 2007;30: 111–9.
• [10]. Butson MJ, Cheung T, Yu P, Metcalfe P. Effects on skin dose from unwanted air gaps under bolus in photon beam radiotherapy. Radiat Meas 2000; 32: 201–4.
• [11]. Khan Y, Villarreal-Barajas JE, Udowicz M, Sinha R, Muhammad W. Clinical and dosimetric implications of air gaps between bolus and skin surface during radiation therapy. J Cancer Ther. 2013;4: 1251–5.
• [12]. Sharma SC, Johnson MW. Surface dose perturbation due to air gap between patient and bolus for electron beams. Med Phys 1993; 20: 377–8.
• [13]. Khan FM. The physics of radiation therapy. 4th ed. Philadelphia, Lippincott Williams & Wilkins, 2010.
• [14]. Şahin S, Gürler O, Gözcü S, Kurt M, Şengül K, Altay A et al. Dosimetric control of dose distribution calculated in computerized treatment planning system. Türk Onkoloji Dergisi 2011;26(4):167-173.
• [15]. Walker M, Visscher S, Barnett E. Comparison of bolus materials to highly absorbent polypropylene and rayon cloth. Journal of Medical Imaging and Radiation Sciences. 2017; 48:55-60.
• [16]. Aras S, Tanzer IO, Ikizceli T. Dosimetric Comparison of Superflab and Specially Prepared Bolus Materials Used in Radiotherapy Practice. Eur J Breast Health. 2020; 16(2): xx.
• [17]. Kong M, Holloway L. An investigation of central axis depth dose distribution perturbation due to an air gap between patient and bolus for electron beams. Australas Phys Eng Sci Med. 2007;30(2):111-9.
• [18]. Kim M, Kudchadker R, Kanke J, Zhang S, Perkins G. Bolus electron conformal therapy for the treatment of recurrent inflammatory breast cancer: a case report. Medical Dosimetry 2012;37: 208-213.
• [19]. Hsu SH, Roberson PL, Chen Y. Assesment of skin dose for breast chest wall radiotherapy as a function of bolus material. Physics in Medicine and Biology 2008;53: 2593-606.
• [20]. Al-Rahbi ZS, Cutajar DL, Metcalfe P, Rosenfeld AB. Dosimetric effects of brass mesh bolus on skin dose and dose at depth for postmastectomy chest wall irradiation. Phys Med. 2018;54: 84-93.