Monte Carlo simulation of the Leksell Gamma Knife®: II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery

Vadim Moskvin, Robert Timmerman, Colleen DesRosiers, Marcus Randall, Paul DesRosiers, Phil Dittmer, Lech Papiez

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

The absence of electronic equilibrium in the vicinity of bone-tissue or air-tissue heterogeneity in the head can misrepresent deposited dose with treatment planning algorithms that assume all treatment volume as homogeneous media. In this paper, Monte Carlo simulation (PENELOPE) and measurements with a specially designed heterogeneous phantom were applied to investigate the effect of air-tissue and bone-tissue heterogeneity on dose perturbation with the Leksell Gamma Knife®. The dose fall-off near the air-tissue interface caused by secondary electron disequilibrium leads to overestimation of dose by the vendor supplied treatment planning software (GammaPlan®) at up to 4 mm from an interface. The dose delivered to the target area away from an air-tissue interface may be underestimated by up to 7% by GammaPlan® due to overestimation of attenuation of photon beams passing through air cavities. While the underdosing near the air-tissue interface cannot be eliminated with any plug pattern, the overdosage due to under-attenuation of the photon beams in air cavities can be eliminated by plugging the sources whose beams intersect the air cavity. Little perturbation was observed next to bone-tissue interfaces. Monte Carlo results were confirmed by measurements. This study shows that the employed Monte Carlo treatment planning is more accurate for precise dosimetry of stereotactic radiosurgery with the Leksell Gamma Knife® for targets in the vicinity of air-filled cavities.

Original languageEnglish
Pages (from-to)4879-4895
Number of pages17
JournalPhysics in Medicine and Biology
Volume49
Issue number21
DOIs
StatePublished - Nov 7 2004

Fingerprint

Radiosurgery
Air
Tissue
air
simulation
dosage
bones
planning
Bone
cavities
photon beams
Photons
Bone and Bones
Planning
attenuation
Monte Carlo simulation
plugging
perturbation
Therapeutics
plugs

ASJC Scopus subject areas

  • Biomedical Engineering
  • Physics and Astronomy (miscellaneous)
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Monte Carlo simulation of the Leksell Gamma Knife® : II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery. / Moskvin, Vadim; Timmerman, Robert; DesRosiers, Colleen; Randall, Marcus; DesRosiers, Paul; Dittmer, Phil; Papiez, Lech.

In: Physics in Medicine and Biology, Vol. 49, No. 21, 07.11.2004, p. 4879-4895.

Research output: Contribution to journalArticle

Moskvin, Vadim ; Timmerman, Robert ; DesRosiers, Colleen ; Randall, Marcus ; DesRosiers, Paul ; Dittmer, Phil ; Papiez, Lech. / Monte Carlo simulation of the Leksell Gamma Knife® : II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery. In: Physics in Medicine and Biology. 2004 ; Vol. 49, No. 21. pp. 4879-4895.
@article{97aed6ec569e45ad9e97c91c860f8db8,
title = "Monte Carlo simulation of the Leksell Gamma Knife{\circledR}: II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery",
abstract = "The absence of electronic equilibrium in the vicinity of bone-tissue or air-tissue heterogeneity in the head can misrepresent deposited dose with treatment planning algorithms that assume all treatment volume as homogeneous media. In this paper, Monte Carlo simulation (PENELOPE) and measurements with a specially designed heterogeneous phantom were applied to investigate the effect of air-tissue and bone-tissue heterogeneity on dose perturbation with the Leksell Gamma Knife{\circledR}. The dose fall-off near the air-tissue interface caused by secondary electron disequilibrium leads to overestimation of dose by the vendor supplied treatment planning software (GammaPlan{\circledR}) at up to 4 mm from an interface. The dose delivered to the target area away from an air-tissue interface may be underestimated by up to 7{\%} by GammaPlan{\circledR} due to overestimation of attenuation of photon beams passing through air cavities. While the underdosing near the air-tissue interface cannot be eliminated with any plug pattern, the overdosage due to under-attenuation of the photon beams in air cavities can be eliminated by plugging the sources whose beams intersect the air cavity. Little perturbation was observed next to bone-tissue interfaces. Monte Carlo results were confirmed by measurements. This study shows that the employed Monte Carlo treatment planning is more accurate for precise dosimetry of stereotactic radiosurgery with the Leksell Gamma Knife{\circledR} for targets in the vicinity of air-filled cavities.",
author = "Vadim Moskvin and Robert Timmerman and Colleen DesRosiers and Marcus Randall and Paul DesRosiers and Phil Dittmer and Lech Papiez",
year = "2004",
month = "11",
day = "7",
doi = "10.1088/0031-9155/49/21/003",
language = "English",
volume = "49",
pages = "4879--4895",
journal = "Physics in Medicine and Biology",
issn = "0031-9155",
publisher = "IOP Publishing Ltd.",
number = "21",

}

TY - JOUR

T1 - Monte Carlo simulation of the Leksell Gamma Knife®

T2 - II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery

AU - Moskvin, Vadim

AU - Timmerman, Robert

AU - DesRosiers, Colleen

AU - Randall, Marcus

AU - DesRosiers, Paul

AU - Dittmer, Phil

AU - Papiez, Lech

PY - 2004/11/7

Y1 - 2004/11/7

N2 - The absence of electronic equilibrium in the vicinity of bone-tissue or air-tissue heterogeneity in the head can misrepresent deposited dose with treatment planning algorithms that assume all treatment volume as homogeneous media. In this paper, Monte Carlo simulation (PENELOPE) and measurements with a specially designed heterogeneous phantom were applied to investigate the effect of air-tissue and bone-tissue heterogeneity on dose perturbation with the Leksell Gamma Knife®. The dose fall-off near the air-tissue interface caused by secondary electron disequilibrium leads to overestimation of dose by the vendor supplied treatment planning software (GammaPlan®) at up to 4 mm from an interface. The dose delivered to the target area away from an air-tissue interface may be underestimated by up to 7% by GammaPlan® due to overestimation of attenuation of photon beams passing through air cavities. While the underdosing near the air-tissue interface cannot be eliminated with any plug pattern, the overdosage due to under-attenuation of the photon beams in air cavities can be eliminated by plugging the sources whose beams intersect the air cavity. Little perturbation was observed next to bone-tissue interfaces. Monte Carlo results were confirmed by measurements. This study shows that the employed Monte Carlo treatment planning is more accurate for precise dosimetry of stereotactic radiosurgery with the Leksell Gamma Knife® for targets in the vicinity of air-filled cavities.

AB - The absence of electronic equilibrium in the vicinity of bone-tissue or air-tissue heterogeneity in the head can misrepresent deposited dose with treatment planning algorithms that assume all treatment volume as homogeneous media. In this paper, Monte Carlo simulation (PENELOPE) and measurements with a specially designed heterogeneous phantom were applied to investigate the effect of air-tissue and bone-tissue heterogeneity on dose perturbation with the Leksell Gamma Knife®. The dose fall-off near the air-tissue interface caused by secondary electron disequilibrium leads to overestimation of dose by the vendor supplied treatment planning software (GammaPlan®) at up to 4 mm from an interface. The dose delivered to the target area away from an air-tissue interface may be underestimated by up to 7% by GammaPlan® due to overestimation of attenuation of photon beams passing through air cavities. While the underdosing near the air-tissue interface cannot be eliminated with any plug pattern, the overdosage due to under-attenuation of the photon beams in air cavities can be eliminated by plugging the sources whose beams intersect the air cavity. Little perturbation was observed next to bone-tissue interfaces. Monte Carlo results were confirmed by measurements. This study shows that the employed Monte Carlo treatment planning is more accurate for precise dosimetry of stereotactic radiosurgery with the Leksell Gamma Knife® for targets in the vicinity of air-filled cavities.

UR - http://www.scopus.com/inward/record.url?scp=8544269388&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=8544269388&partnerID=8YFLogxK

U2 - 10.1088/0031-9155/49/21/003

DO - 10.1088/0031-9155/49/21/003

M3 - Article

C2 - 15584525

AN - SCOPUS:8544269388

VL - 49

SP - 4879

EP - 4895

JO - Physics in Medicine and Biology

JF - Physics in Medicine and Biology

SN - 0031-9155

IS - 21

ER -