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Journal of Radiation Oncology

, Volume 8, Issue 2, pp 233–238 | Cite as

Quantitative assessment of the efficacy of two different treatment plan optimization algorithms in treating tumors in locations of high heterogeneity

  • E. Ishmael ParsaiEmail author
  • Vincent Ulizio
  • Jacob M. Eckstein
  • Krishna Reddy
Original Research
  • 8 Downloads

Abstract

Purpose

The purpose of this study is to evaluate the differences in treatment optimization algorithms in two leading treatment planning systems, Pinnacle v9.8 (Philips Healthcare, Amsterdam, Netherlands) and Raystation 8A (Raysearch Americas Inc., Garden City, USA). The aim is to compare and contrast between planning systems in terms of sparing of vital organs (SVO) using several gradient and conformity indices, as well as vital organ dose limits.

Methods

The study includes patients (N = 18) presenting with lung (10), liver (4), and head and neck (4) tumors and treated with intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) planned using the same objectives and weights, number of iterations, beam angles, and planning target volume (PTV) coverage. Both plans were analyzed for Radiation Therapy Oncology Group (RTOG) conformity index, Paddick conformity index, gradient index (GI), dose gradient index, and sparing of vital organs. This study utilized both segmented and dynamic approaches to multileaf collimation (SMLC and DMLC, respectively) in the Raystation planning system in lung IMRT plans, as some plans could not be optimized in Raystation with SMLC (7).

Results

It was determined that in lung plans, Pinnacle demonstrated better sparing of the right lung and the spinal cord, but Raystation more effectively spared the heart and esophagus. In liver plans, Raystation demonstrated a superior GI, indicating faster dose falloff; this correlated with lower volumes of the liver receiving 24 Gy. In head and neck (H&N) plans, Pinnacle demonstrated superior sparing of the parotid but inferior GI, indicating more rapid dose falloff in Raystation beyond the PTV.

Conclusions

The analysis for the lung, liver, and H&N cases indicated that both planning systems are equivocal for the majority of parameters measured, with a few differentiating trends. In H&N plans, Pinnacle showed improved parotid sparing but inferior performance in calculated GI values. Liver plans showed superiority of Raystation in GI computations, but the most notable differences were in the lung plans where Pinnacle spared the spinal cord significantly more in contrast to Raystation’s performance but also delivered significantly more dose to the esophagus.

Keywords

Treatment planning system TPS Dosimetry Conformity 

Abbreviations

PCI

Paddick conformity index

RTOGCI

RTOG conformity index

CN

conformation number

CNS

central nervous system

CT

computed tomography

CTV

clinical target volume

IDL

isodose line

DGI

dose gradient index

DVH

dose-volume histogram

DMLC

dynamic multileaf collimator

GI

gradient index

GTV

gross tumor volume

IMRT

intensity modulated radiation therapy

LL

left lung

LP

left parotid

MLC

multileaf collimator

OAR

organ at risk

PI

prescription isodose

PIV

prescription isodose volume

PIV50%

volume of the 50% prescription isodose

PTV

planning target volume

Reff,50%Rx

effective radius of the 50% prescription isodose

Reff,Rx

effective radius of the prescription isodose

RL

right lung

RP

right parotid

ROI

region of interest

RTOG

Radiation Therapy Oncology Group

SMLC

segmented multileaf collimator

SRS

stereotactic radiosurgery

SVO

sparing of vital organs

TPS

treatment planning system

TV

target volume, defined as the PTV for this study

TVPIV

volume of prescription isodose located within the target volume

VOAR

volume of organ at risk

Notes

Compliance with ethical standards

Funding

No funding was received for this study.

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed consent

Statement of informed consent was not applicable since the manuscript does not contain any patient data.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Radiation OncologyUniversity of Toledo Medical CenterToledoUSA

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