Dosimetric Characteristics of Transparent Bolus for External Beam Radiotherapy

Document Type: Original Paper

Authors

1 Research and development centre,Bharathiar University,Coimbatore,India

2 Dept. of Radiotherapy, Madurai Medical College & Govt. Rajaji Hospital, Madurai, India.

3 Dept.of Medical Physics, Bharathidasan University, Tiruchirapalli, India

Abstract

Abstract

Introduction
In radiotherapy, the bolus is often used while treating the tumour under the uneven surfaces of the patients for correcting the anatomical irregularities and increasing skin dose, so that the prescribed dose is uniformly delivered. Wet cotton and wet gauze bolus are still used in developing countries for reducing the cost and often because of the non-availability of commercial bolus material. Since the use of wet cotton and wet gauze has certain disadvantages, there is a need for transparent bolus which should be similar to universally accepted bolus in properties and also 50% less expensive.

Materials and Method
In the present study, transparent bolus (Senflab) material was prepared. We studied the characteristics of the bolus such as transmission factor, Percentage Depth Dose (PDD), stability over time, stability over high dose, homogeneity and transparency. We compared the new bolus material with those of the commercially available Superflab and RW3 slab.

Result
The percentage difference of the transmission factor of Senflab was less than ±1.9% compared with Superflab and RW3. For PDD, the percentage difference was ±2.88% on photons. Similarly, for electron, it was ±1.26%. The performance of bolus remained constant both physically and dosimetrically after higher dose exposure; the percentage standard deviation was 0.0002% for a period of one month, and that for the homogeneity it was 0.0003%. The transparency of the bolus material was good enough to display the set radiation treatment field.

Conclusion
This study shows the suitability of the new bolus for routine use in radiotherapy.

Keywords

Main Subjects



Articles in Press, Accepted Manuscript
Available Online from 05 May 2019
  • Receive Date: 22 January 2019
  • Revise Date: 02 May 2019
  • Accept Date: 05 May 2019