Characteristic of natural rubber as bolus material for radiotherapy

• Published in: Materials research express 2018-08, Vol.5 (9), p.95302
• Main Authors: Supratman, Astri Suppa, Sutanto, Heri, Hidayanto, Eko, Jaya, Gede Wiratma, Astuti, Santi Yuli, Budiono, Tris, Firmansyah, Muhammad Agus
• Format: Article
• Language: English
• Subjects: bolus; effective atomic number; mass attenuation coefficients; natural rubber; percentage of surface dose; relative electron density; soft tissue
• ISSN: 2053-1591; 2053-1591
• DOI: 10.1088/2053-1591/aad5ca

Bolus is material similar to tissue and is placed directly on skin surface during radiotherapy with electron beam. This research has successfully developed bolus using Natural Rubber (NR) organic polymer. The bolus produced has a dimension of 11 × 11 × 0.5 cm3. This bolus has also undergone characteristics testing using CT-Scan to measured relative electron density (RED). The mass attenuation coefficients (MAC) testing was calculated using software XCOM Version 3.1 and effective atomic number (EAN) testing was calculated using Auto Zeff Version 1.7. Bolus was exposured to electron beam radiation with energy 8 and 10 MeV using Linear Accelerator (LINAC) to measure the percentage of surface dose (PSD) value. Results show that the bolus has RED value of 0.893, which is nearly the same as that of soft tissues such as Lung, Fat, and Liver. For MAC calculation result is similar with water and soft tissue (lung), and for EAN calculation result is under water and soft tissue. The Percentage of Surface Dose (PSD) values while using bolus were 94.63% and 95.31% for 8 and 10 MeV energies, respectively. These values mean that there has been an increase in PSD with the use of bolus, even though it is not yet 100%. Hence, NR is an alternative material for bolus as it is similar to soft tissue and helps to increase the dose on skin surface.