lei xing , ph.d. & jacob haimson professor stanford...

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@01-258_via99-011_hepatoma_onscreen

Department of Radiation Oncology & MIPS Stanford University School of Medicine

Lei Xing , Ph.D. & Jacob Haimson Professor

6/30/13 ……………………………

Imaging

3D modeling Treatment planning Pt setup and treatment delivery

4D modeling

Gated tx planning

4D planning

Adaptive therapy (imaging, planning, delivery)

Day 0 Day 14 Day 24

3D/4D CBCT 4D imaging Biological imaging

6/30/13

Case study – TrueBeam 6 MV FFF RapidArc Tx of a Lung SBRT

6/30/13

Supine Craniospinal Irradiation with RA Jianzhou Chen, Z. Chen, T. Atwood, I. Gibbs, S. Soltys, & L. Xing, Supine Craniospinal Irradiation with VMAT to Improve Target Dose Conformity and Homogeneity, JRO, 2012.

Head and neck CT, PET, and IMRT treatment plan

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Available Imaging Tools

Spatial resolution

sens

itivi

ty

XLCT

XFCT

PET

SPECT

CT

MRI

Optical imaging

US

MRSI

Radioluminescence & X-ray Luminescence CT

Ionizing radiation Optical radiation

-  PET and SPECT scintillators -  CT detectors

-  Portal imaging

-  Dosimetry -  Scintillation counting

-  High-energy physics

Current applications

Principle

G. Pratx, 2012

CT Molecular Imaging using nanophosphors

a

Pratx, Sun, Carpenter & Xing, Optics Letters, 2011.

CT Molecular Imaging using QD and nanophosphors

a b c d

QD705 QD800

6/30/13

a b

h A

B C D

E

F

Modification of QD710-Dendron with a dimeric RGD peptide, RGD2. B: Excellent solubility and monodisperity in aqueous solution for the QD710-Dendron (left) and QD710-RGD2 (right). C: TEM image of QD710-RGD2. D: UV absorbance and NIRF of the QD710-Dendron (bottom) and QD710-RGD2 (top). In vivo NIRF imaging of QD710-RGD2 (active targeting, E) and QD710-Dendron (passive targeting, F) in mice bearing SKOV3 tumor (Cheng’s lab).

QD710-RGD peptide

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Phos

Phos in

Agar

Varian 100keV fluoro

Gd2O2S:Eu LaO2:Eu

Photon yield vs dose

The white light image (a) and luminescence image (b) of the nanophosphor phantom. (c) X-ray luminescence spectrum of Gd2O2S:Eu. The Gd2O2S:Eu phantoms with different concentrations (d) and their X-ray luminescence images under different X-ray irradiation dose 1 cGy (e), 10 cGy (f) and 100 cGy (g).

White light Luminescence

a b

cTissue-mimicking

material 1 cGy

10 cGy 100 cGy

0.3 pM

0.1

0.250.5

0.75

1

2 µg/mL

d e

f g

6/30/13

(a) Schematic of the locations of each type of RLNP. The inactive particles are indicated with the abbreviation (Ctrl). (b,c) The unmixed signal from the BaYF4:Tb and BaYF4:Eu particles, respectively. (d) The unmixed multiplexed image with colorbars for the relative concentrations of BaYF4:Tb and BaYF4:Eu. (C. Carpenter et al, 2012) !

Multiplexing

!

6/30/13

X-ray induced optical luminescence images

BSA-Au25Lysozyme-Au8ssDNA-Agx

6

8

4.BSA-

3.Lyz-

2. ssDNA-

Blank 1.Water

2

4Int.

1

BSAAu25

LyzAu8

ssDNAAgx

Water1 2 3 4

0

X-ray induced optical luminescence intensities

Gultathione-Au18??Gultathione Au18?? Or

polymer-Au ion complex

40

60

Blank 1.Water

2. solution

3.solid

20

Int.

3

Water solution solid1 2 3

0

4


X-ray Luminescence TomographyG. Pratx et al, IEEE Trans. Med. Ima., 2010

1% Agar 99% water TiO2 for optical sctter Ink for optical absorption 100 µM phosphor

1cm phosphor plug

6/30/13

Reconstruction: ML-EM

Log-likelihood:

Yi ~ Poisson(yi) Noise from counting statistics:

Optimization:

Expectation-Maximization:

6/30/13

Molecular sensitivity = 0.3 pM @ 1cGy

Tissue-mimicking material

0.1

0.25

0.5

0.75

1

2 µg/mL

1 cGy 10 cGy

100 cGy

0.3 pM

6/30/13

Spatially Encoded Light Emission

X-ray Luminescence Tomography 6/30/13

C. Carpenter et al, PMB 2012

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Spatial resolution ~ 1 mm

4 mm 3

2

1.5 1

0.5

64 angles 128 angles

50 ra

dial

pos

ition

s 10

0 ra

dial

pos

ition

s

Reconstruction & linearity

Phantom

Reconstructed image (ML-EM)

10 mg/mL 5

1

Offset (background)

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Sinogram

10 mg/mL

1 mg/mL

5 mg/mL

6/30/13

Simulation vs Experiment S

imul

atio

n E

xper

imen

t

Sinogram Reconstructed image

6/30/13

X-ray Fluorescence Molecular CT Imaging

M. Balazova, Y. Kuang, G. Pratx, L. Xing, X-ray Fluorescence Molecular CT Imaging, IEEE Trans Med Ima., 2012

Sinograms (top) and reconstructed CT images (bottom) for XFCT (left) and transmission CT (right) of the low-resolution phantom loaded with gold for a

0.1 mGy imaging dose. (Magda Bozalova et al)

XFCT CT



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Au

Pt

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6/30/13

Fig. 1. (left) Proposed XFCT/CT system. (top) Physical mechanism of X-ray fluorescence from K-shell electrons.


K. Yu et al, AAPM 2012 (best paper in imaging) Medical Physics Letters, 2013.

Multiplexing

K. Yu et al, AAPM 2012 (best paper in imaging) Medical Physics Letters, 2013.

Multiplexing

6/30/13 K. Yu et al, AAPM 2012 (best paper in imaging) Medical Physics Letters, 2013.

Overcoming Compton Scatter

Moiz Ahmad et al, Order of Magnitude Sensitivity Increase in X-ray Fluorescence CT (XFCT) Imaging With an Optimized Spectro Ima, 2013

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Magda Bazalova, to be published, 2013

Going Beyond K-Schell Imaging CT FBP ML-EM (w/o correction) ML-EM (w correction)

15 k

eV

30 k

eV

80 k

eV

Figure 2: CT images (first column, W/L = 800/0) and XFCT images reconstructed with filtered back-projection (FBP, second column) and maximum likelihood expectation maximization (ML-EM, 20

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High-sensitivity x-ray fluorescence CT imaging of Cisplatin with L-shell x-rays

Magda Bazalova et al, to be published

Figure 5: Profiles along a horizontal (left) and vertical (right) line across the phantom for the 15 keV images reconstructed with FBP (green), ML-EM without (blue) and with (red) attenuation correction.The actual profile is marked by the black dashed line. The accuracy of concentration reconstruction is significantly increased when attenuation correction is applied.

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High-sensitivity x-ray fluorescence CT imaging of Cisplatin with L-shell x-rays X-ray acoustic tomography (XACT) with pulsed

X-ray beam from a medical linear accelerator

!

Liangzhong Xiang, Bin Han, Colin Carpenter, Guillem Pratx, Yu Kuang, and Lei Xing

30 picoseconds per pulse Xiang L et al, Medical Physics Letters, 2013

  Interaction of X-ay with endogenous or exogenous media provides the basis for X-ray molecular imaging.  

imaging is possible.   XFCT, XLCT and XACT are a few examples of

X-ray molecular/physiological imaging that are being developed at Stanford.

lei xing , ph.d. & jacob haimson professor stanford...

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