Ion range estimation by using dual energy computed tomography

被引:51
作者
Huenemohr, Nora [1 ]
Krauss, Bernhard [2 ]
Dinkel, Julien [1 ,3 ]
Gillmann, Clarissa [1 ,5 ]
Ackermann, Benjamin [4 ]
Jaekel, Oliver [1 ,4 ,5 ]
Greilich, Steffen [1 ]
机构
[1] German Canc Res Ctr, D-69120 Heidelberg, Germany
[2] Siemens AG, Imaging & Therapy, Forchheim, Germany
[3] Massachusetts Gen Hosp, Boston, MA 02114 USA
[4] Heidelberg Ion Beam Therapy Ctr HIT, Heidelberg, Germany
[5] Univ Heidelberg Hosp, Heidelberg, Germany
来源
ZEITSCHRIFT FUR MEDIZINISCHE PHYSIK | 2013年 / 23卷 / 04期
关键词
Heavy ion therapy; proton therapy; dual energy CT; stopping powers; WEPL; MONTE-CARLO SIMULATIONS; CT NUMBERS; RADIOTHERAPY; TISSUE; CALIBRATION; SINGLE; MODEL;
D O I
10.1016/j.zemedi.2013.03.001
中图分类号
R8 [特种医学]; R445 [影像诊断学];
学科分类号
1002 ; 100207 ; 1009 ;
摘要
Inaccurate conversion of CT data to water-equivalent path length (WEPL) is one of the most important uncertainty sources in ion treatment planning. Dual energy CT (DECT) imaging might help to reduce CT number ambiguities with the additional information. In our study we scanned a series of materials (tissue substitutes, aluminum, PMMA, and other polymers) in the dual source scanner (Siemens Somatom Definition Flash). Based on the 80 kVp/140Sn kVp dual energy images, the electron densities rho(e) and effective atomic numbers Z(eff) were calculated. We introduced a new lookup table that translates the rho(e) to the WEPL. The WEPL residuals from the calibration were significantly reduced for the investigated tissue surrogates compared to the empirical Hounsfield-look-up table (single energy CT imaging) from (-1.0 +/- 1.8)% to (0.1 +/- 0.7)% and for non-tissue equivalent PMMA from -7.8% to -1.0%. To assess the benefit of the new DECT calibration, we conducted a treatment planning study for three different idealized cases based on tissue surrogates and PMMA. The DECT calibration yielded a significantly higher target coverage in tissue surrogates and phantom material (i.e. PMMA cylindo; mean target coverage improved from 62% to 98%). To verify the DECT calibration for real tissue, ion ranges through a frozen pig head were measured and compared to predictions calculated by the standard single energy CT calibration and the novel DECT calibration. By using this method, an improvement of ion range estimation from -2.1% water-equivalent thickness deviation (single energy CT) to 0.3% (DECT) was achieved. If one excludes raypaths located on the edge of the sample accompanied with high uncertainties, no significant difference could be observed.
引用
收藏
页码:300 / 313
页数:14
相关论文
共 29 条
[1]   ENERGY-SELECTIVE RECONSTRUCTIONS IN X-RAY COMPUTERIZED TOMOGRAPHY [J].
ALVAREZ, RE ;
MACOVSKI, A .
PHYSICS IN MEDICINE AND BIOLOGY, 1976, 21 (05) :733-744
[2]   On the clinical spatial resolution achievable with protons and heavier charged particle radiotherapy beams [J].
Andreo, Pedro .
PHYSICS IN MEDICINE AND BIOLOGY, 2009, 54 (11) :N205-N215
[3]  
[Anonymous], DGMP TAG 2008
[4]   INVESTIGATION OF THE ELECTRONIC-ENERGY LOSS OF HYDROGEN-IONS IN H2O - INFLUENCE OF THE STATE OF AGGREGATION [J].
BAUER, P ;
KAFERBOCK, W ;
NECAS, V .
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 1994, 93 (02) :132-136
[5]   Dual-energy CT-based material extraction for tissue segmentation in Monte Carlo dose calculations [J].
Bazalova, Magdalena ;
Carrier, Jean-Francois ;
Beaulieu, Luc ;
Verhaegen, Frank .
PHYSICS IN MEDICINE AND BIOLOGY, 2008, 53 (09) :2439-2456
[6]  
Berger M.J., 2010, NIST STANDARD REFERE, V8, DOI DOI 10.18434/T48G6X
[7]   EXPLANATION OF CEREBRAL WHITE-GRAY CONTRAST IN COMPUTED-TOMOGRAPHY [J].
BROOKS, RA ;
DICHIRO, G ;
KELLER, MR .
JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 1980, 4 (04) :489-491
[8]   QUANTITATIVE THEORY OF HOUNSFIELD UNIT AND ITS APPLICATION TO DUAL ENERGY SCANNING [J].
BROOKS, RA .
JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 1977, 1 (04) :487-493
[9]   TREATMENT PLANNING FOR HEAVY-ION RADIOTHERAPY [J].
CHEN, GTY ;
SINGH, RP ;
CASTRO, JR ;
LYMAN, JT ;
QUIVEY, JM .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1979, 5 (10) :1809-1819
[10]   A consistent dielectric response model for water ice over the whole energy-momentum plane [J].
Emfietzoglou, D. ;
Nikjoo, H. ;
Petsalakis, I. D. ;
Pathak, A. .
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 2007, 256 (01) :141-147