open access

Vol 24, No 6 (2019)
Original research articles
Published online: 2019-11-01
Submitted: 2018-12-05
Get Citation

Biological dose-enhancement analysis with Monte Carlo simulation for Lipiodol for photon beams

Daisuke Kawahara, Shuichi Ozawa, Hisashi Nakano, Katsumaro Kubo, Takehiro Shiinoki, Tomoki Kimura, Yasushi Nagata
DOI: 10.1016/j.rpor.2019.10.006
·
Rep Pract Oncol Radiother 2019;24(6):681-687.

open access

Vol 24, No 6 (2019)
Original research articles
Published online: 2019-11-01
Submitted: 2018-12-05

Abstract

Background

Previously, the physical dose-enhancement factor (DphysEF) enhancement was introduced. However, the dose enhancement considering the biological effectiveness was not shown.

Purpose

The aim of the current study was to evaluate the biological dose-enhancement factor (DbioEF) by the dose rate and to compare the DphysEF and the DbioEF in Lipiodol for liver Stereotactic Body Radiation Therapy (SBRT).

Materials and methods

Flattening-filter-free (FFF) 6-MV (6MVX) and 10MVX beams were delivered by TrueBeam. A virtual inhomogeneity phantom and a liver SBRT patient-treatment plan were used. The DphysEF and lineal energy distribution ([[mml:math altimg="si8.gif"]][[mml:mi]]y[[/mml:mi]][[/mml:math]]) distribution was calculated from Monte Carlo simulations. Using a microdosimetric-kinetic (MK) model that is estimated based on the linear-quadratic formula for Lipiodol using human liver hepatocellular cells (HepG2), the biological dose and biological dose enhancement factor (DbioEF) were calculated. The dose rate in the simulation was changed from 0.1 to 24Gy/min.

Results

The DbioEF (DR:2Gy/min) and DphysEF with 10MVX FFF beam were 23.2% and 19.1% at maximum and 12.8% and 11.1% on average in the Lipiodol. In the comparison of the DbioEF between 0.1–24Gy/min, the DbioEF was 21.2% and 11.1% with 0.1Gy/min for 6MVX and 10 MVX, respectively. The DbioEF was larger than DEF for the 6MVX and 10MVX FFF beams. In clinical cases with the 10MVX FFF beam, the DbioEF and DphysEF in the Lipiodol region can increase the in-tumor dose by approximately 11% and 10%, respectively, without increasing the dose to normal tissue.

Conclusions

The lower-energy and higher-dose-rate beams were contributed to the biological dose. The Lipiodol caused the enhancement of the physical dose and biological effectiveness.

Advances in knowledge

The biological dose enhancement (DbioEF) should be considered in the high-density material such as the Lipiodol.

Abstract

Background

Previously, the physical dose-enhancement factor (DphysEF) enhancement was introduced. However, the dose enhancement considering the biological effectiveness was not shown.

Purpose

The aim of the current study was to evaluate the biological dose-enhancement factor (DbioEF) by the dose rate and to compare the DphysEF and the DbioEF in Lipiodol for liver Stereotactic Body Radiation Therapy (SBRT).

Materials and methods

Flattening-filter-free (FFF) 6-MV (6MVX) and 10MVX beams were delivered by TrueBeam. A virtual inhomogeneity phantom and a liver SBRT patient-treatment plan were used. The DphysEF and lineal energy distribution ([[mml:math altimg="si8.gif"]][[mml:mi]]y[[/mml:mi]][[/mml:math]]) distribution was calculated from Monte Carlo simulations. Using a microdosimetric-kinetic (MK) model that is estimated based on the linear-quadratic formula for Lipiodol using human liver hepatocellular cells (HepG2), the biological dose and biological dose enhancement factor (DbioEF) were calculated. The dose rate in the simulation was changed from 0.1 to 24Gy/min.

Results

The DbioEF (DR:2Gy/min) and DphysEF with 10MVX FFF beam were 23.2% and 19.1% at maximum and 12.8% and 11.1% on average in the Lipiodol. In the comparison of the DbioEF between 0.1–24Gy/min, the DbioEF was 21.2% and 11.1% with 0.1Gy/min for 6MVX and 10 MVX, respectively. The DbioEF was larger than DEF for the 6MVX and 10MVX FFF beams. In clinical cases with the 10MVX FFF beam, the DbioEF and DphysEF in the Lipiodol region can increase the in-tumor dose by approximately 11% and 10%, respectively, without increasing the dose to normal tissue.

Conclusions

The lower-energy and higher-dose-rate beams were contributed to the biological dose. The Lipiodol caused the enhancement of the physical dose and biological effectiveness.

Advances in knowledge

The biological dose enhancement (DbioEF) should be considered in the high-density material such as the Lipiodol.

Get Citation

Keywords

Radiobiological dose enhancement; Lipiodol; Monte Carlo calculation; MK model

About this article
Title

Biological dose-enhancement analysis with Monte Carlo simulation for Lipiodol for photon beams

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 24, No 6 (2019)

Pages

681-687

Published online

2019-11-01

DOI

10.1016/j.rpor.2019.10.006

Bibliographic record

Rep Pract Oncol Radiother 2019;24(6):681-687.

Keywords

Radiobiological dose enhancement
Lipiodol
Monte Carlo calculation
MK model

Authors

Daisuke Kawahara
Shuichi Ozawa
Hisashi Nakano
Katsumaro Kubo
Takehiro Shiinoki
Tomoki Kimura
Yasushi Nagata

Important: This website uses cookies. More >>

The cookies allow us to identify your computer and find out details about your last visit. They remembering whether you've visited the site before, so that you remain logged in - or to help us work out how many new website visitors we get each month. Most internet browsers accept cookies automatically, but you can change the settings of your browser to erase cookies or prevent automatic acceptance if you prefer.

By "Via Medica sp. z o.o." sp.k., ul. Świętokrzyska 73, 80–180 Gdańsk, Poland
tel.:+48 58 320 94 94, fax:+48 58 320 94 60, e-mail: journals@viamedica.pl