Vol 26, No 2 (2021)
Research paper
Published online: 2021-03-04

open access

Page views 674
Article views/downloads 586
Get Citation

Connect on Social Media

Connect on Social Media

A three-dimensional printed customized bolus: adapting to the shape of the outer ear

Gorka Gomez1, Montserrat Baeza2, Juan Carlos Mateos3, Jose Antonio Rivas2, Florencio Javier Luis Simon2, Diego Mesta Ortega4, María de los Ángeles Flores Carrión5, Eleonor Rivin del Campo6, Tomas Gómez-Cía78, Jose Luis Lopez Guerra47
Rep Pract Oncol Radiother 2021;26(2):211-217.

Abstract

Background: The skin-sparing effect of megavoltage-photon beams in radiotherapy (RT) reduces the target coverage of superficial tumours. Consequently, a bolus is widely used to enhance the target coverage for superficial targets. This study evaluates a three-dimensional (3D)-printed customized bolus for a very irregular surface, the outer ear.

Materials and methods: We fabricated a bolus using a computed tomography (CT) scanner and evaluated its efficacy. The head of an Alderson Rando phantom was scanned with a CT scanner. Two 3D boluses of 5- and 10-mm thickness were designed to fit on the surface of the ear. They were printed by the Stratasys Objet260 Connex3 using the malleable “rubber-like” photopolymer Agilus. CT simulations of the Rando phantom with and without the 3D and commercial high density boluses were performed to evaluate the dosimetric properties of the 3D bolus. The prescription dose to the outer ear was 50 Gy at 2 Gy/fraction.

Results: We observed that the target coverage was slightly better with the 3D bolus of 10 mm compared with the commercial one (D98% 98.2% vs. 97.6%).The maximum dose was reduced by 6.6% with the 3D bolus and the minimum dose increased by 5.2% when comparing with the commercial bolus. In addition, the homogeneity index was better for the 3D bolus (0.041 vs. 0.073).

Conclusion: We successfully fabricated a customized 3D bolus for a very irregular surface. The target coverage and dosimetric parameters were at least comparable with a commercial bolus. Thus, the use of malleable materials can be considered for the fabrication of customized boluses in cases with complex anatomy.

Article available in PDF format

View PDF Download PDF file

References

  1. Jung NH, Shin Y, Jung IH, et al. Feasibility of normal tissue dose reduction in radiotherapy using low strength magnetic field. Radiat Oncol J. 2015; 33(3): 226–232.
  2. Hogstrom K. Treatment Planning in Electron Beam Therapy. Front Radiat Ther Oncol. : 30–52.
  3. Guadagnolo BA, Zagars GK, Araujo D, et al. Outcomes after definitive treatment for cutaneous angiosarcoma of the face and scalp. Head Neck. 2011; 33(5): 661–667.
  4. Tieu MT, Graham P, Browne L, et al. The effect of adjuvant postmastectomy radiotherapy bolus technique on local recurrence. Int J Radiat Oncol Biol Phys. 2011; 81(3): e165–e171.
  5. Park JW, Oh SeAn, Yea JiW, et al. Fabrication of malleable three-dimensional-printed customized bolus using three-dimensional scanner. PLoS One. 2017; 12(5): e0177562.
  6. Valverde I, Gomez-Ciriza G, Hussain T, et al. Three-dimensional printed models for surgical planning of complex congenital heart defects: an international multicentre study. Eur J Cardiothorac Surg. 2017; 52(6): 1139–1148.
  7. Burleson S, Baker J, Hsia AnT, et al. Use of 3D printers to create a patient-specific 3D bolus for external beam therapy. J Appl Clin Med Phys. 2015; 16(3): 5247.
  8. Park K, Park S, Jeon MJ, et al. Clinical application of 3D-printed-step-bolus in post-total-mastectomy electron conformal therapy. Oncotarget. 2017; 8(15): 25660–25668.
  9. Bethesda MICoRUaM: ICRU Report 83.. Prescribing, Recording, and Reporting Photon-Beam Intensity-Modulated Radiation Therapy (IMRT). J ICRU. 2010; 10(1).
  10. Carrasco MA, Perucha M, Luis FJ, et al. A comparison between radiochromic EBT2 film model and its predecessor EBT film model. Phys Med. 2013; 29(4): 412–422.
  11. Vyas V, Palmer L, Mudge R, et al. On bolus for megavoltage photon and electron radiation therapy. Med Dosim. 2013; 38(3): 268–273.
  12. Butson M, Cheung T, Yu P, et al. Effects on skin dose from unwanted air gaps under bolus in photon beam radiotherapy. Radiat Measure. 2000; 32(3): 201–204.
  13. Fujimoto K, Shiinoki T, Yuasa Y, et al. Efficacy of patient-specific bolus created using three-dimensional printing technique in photon radiotherapy. Phys Med. 2017; 38: 1–9.
  14. Park JW, Yea JW, Park JW, et al. Three-dimensional customized bolus for intensity-modulated radiotherapy in a patient with Kimura's disease involving the auricle. Cancer Radiother. 2016; 20(3): 205–209.
  15. Kim SW, Shin HJ, Kay CS, et al. A customized bolus produced using a 3-dimensional printer for radiotherapy. PLoS One. 2014; 9(10): e110746.
  16. Robar JL, Moran K, Allan J, et al. Intrapatient study comparing 3D printed bolus versus standard vinyl gel sheet bolus for postmastectomy chest wall radiation therapy. Pract Radiat Oncol. 2018; 8(4): 221–229.



Reports of Practical Oncology and Radiotherapy