Stanford Cancer Imaging Training (SCIT) Program

SCIT Program Seminars

The SCIT program hosts a quarterly colloquium during which two trainees present the status of their research.

NEXT SEMINARS:

Wednesday, December 10, 2014
10:00 am
Glazer Learning Center (Lucas, P083)

"Noninvasive Magnetogenetic Cancer Therapy"
Ryan Spitler, PhD

Abstract: Many cancer therapies are insufficient due to lack of efficacy, feasibility, specificity and sensitivity. To address the pressing unmet clinical need for effective cancer therapy we are developing a multimodal approach for targeting and monitoring of tumors in vivo. We propose the development of cell-directed magnetotactic bacteria (MTB), which will represent a new nanoplatform for detection and control of cancer. This will be accomplished by using the microaerophilic Gram-negative α-proteobacterium, Magnetospirillum magneticum strain AMB-1 (AMB-1), an MTB that synthesizes lipid-enclosed magnetic nanoparticles (magnetosomes). Magnetosomes are able to selectively absorb low frequency alternating magnetic fields (AMFs), which are dissipated as heat, a process called magnetic hyperthermia. The applied AMF is strong enough for tumor ablation, however can be fine tuned for only small changes in temperature which may be used to drive heat induced gene expression. The MTB alone or loaded into immune cells in this approach may serve as both the tumor homing entity as well as the source of the imaging and therapeutic element—the magnetosome. This platform will be capable of new cancer control and detection capabilities, such as early in vivo detection, tracking of cancer cell extravasation, migration and metastasis formation, tracking of immune cell homing to cancer cells, selective heating of cancer cells and selective sorting and extraction of circulating tumor cells in vivo.

"Ultrasound-guided Delivery of microRNA Loaded Nanoparticles Into Cancer"
Tzu-Yin Wang, PhD

Abstract: Ultrasound induced microbubble cavitation can cause enhanced permeability across natural barriers of tumors such as vessel walls or cellular membranes, allowing for enhanced therapeutic delivery into the target tissues. While enhanced delivery of small (<1 nm) molecules has been shown at acoustic pressures below 1MPa both in vitro and in vivo, the delivery efficiency of larger (>100 nm) therapeutic carriers into cancer remains unclear and may require a higher pressure for sufficient delivery. Enhanced delivery of larger therapeutic carriers such as FDA approved pegylated poly(lactic-co-glycolic acid) nanoparticles (PLGA-PEG-NP) has significant clinical value because these nanoparticles have been shown to protect encapsulated drugs from degradation in the blood circulation and allow for slow and prolonged release of encapsulated drugs at the target location. In this study, various acoustic parameters were investigated to facilitate the successful delivery of two nanocarriers, a fluorescent semiconducting polymer model drug nanoparticle as well as PLGA-PEG-NP into human colon cancer xenografts in mice. We first measured the cavitation dose produced by various acoustic parameters (pressure, pulse length, and pulse repetition frequency) and microbubble concentration in a tissue mimicking phantom. Next, in vivo studies were performed to evaluate the penetration depth of nanocarriers using various acoustic pressures, ranging between 1.7 and 6.9 MPa. Finally, a therapeutic microRNA, miR-122, was loaded into PLGA-PEG-NP and the amount of delivered miR-122 was assessed using quantitative RT-PCR. Our results show that acoustic pressures had the strongest effect on cavitation. An increase of the pressure from 0.8 to 6.9 MPa resulted in a nearly 50-fold increase in cavitation in phantom experiments. In vivo, as the pressures increased from 1.7 to 6.9 MPa, the amount of nanoparticles deposited in cancer xenografts was increased from 4- to 14-fold, and the median penetration depth of extravasated nanoparticles was increased from 1.3-fold to 3-fold, compared to control conditions without ultrasound, as examined on 3D confocal microscopy. When delivering miR-122 loaded PLGA-PEG-NP using optimal acoustic settings with minimum tissue damage, miR-122 delivery into tumors with ultrasound and microbubbles was 7.9-fold higher compared to treatment without ultrasound. This study demonstrates that ultrasound induced microbubble cavitation can be a useful tool for delivery of therapeutic miR loaded nanocarriers into cancer in vivo.



Previous Seminars

Optimization of a Fast CT System for More Accurate Radiotherapy
Erica Cherry, PhD
August 27, 2014

Iron Oxide Nanoparticles Inhibit Tumor Growth
Saeid Zanganeh, PhD
August 27, 2014


Image-guided Ultrasound Facilitated Drug Delivery Into Tumors In Vivo
Tzu-Yin Wang, PhD
May 7, 2014

Novel Radiation Detector Capable of Measuring the Energy of Individual X-ray Photons at High-Flux Rates to Advance X-ray Imaging Technologies for Cancer
Mehmet Gunhan Ertosun, PhD
May 7, 2014


Wide-Field Fluorescence Endoscopy and Dual-Axis Confocal Microscopy For Targeted Imaging of Cathepsin Activity in Colon Cancer
Steven Sensarn, PhD
February 5, 2014

Using High-Energy Electrons for Radiation Treatments and Cancer Imaging
Erica Cherry, PhD
February 5, 2014


Endoluminal Approaches to MRI-guided Ultrasonic Ablation of Tumors
Graham Sommer, MD
October 2, 2013

Image-guided Ultrasound Facilitated Drug Delivery Into Tumors: Optimization of Treatment Strategy Based on Quantitative Measurement of Cavitation
Tzu-Yin Wang, PhD
October 2, 2013


Making Sense of Optical Contrast for Point-of-Care Pathology
Steven Sensarn, PhD
June 19, 2013

Quantitative Analysis of Bone Tumors on Radiography: A Step Towards Diagnostic Imaging Based Analytics
Bhavya Shah, MD
June 19, 2013


T2-weighted Contrast in Breast MRI
Catherine Moran, PhD
March 22, 2013

3D MDCT Detection of Extrapancreatic Perineural Spread in Pancreatic Adenocarcinoma: A Radiologic Biomarker?
Bhavik Patel, MD
March 22, 2013



MRI-Based Biomarkers of Therapeutic Response in Triple-Negative Breast Cancer
Daniel Golden, PhD
December 12, 2012

Technical Development and Clinical Evaluation of Diffraction Enhanced Imaging for Breast Applications
Christopher Parham, MD, PhD
December 12, 2012


Fluorescence Imaging of Cancer Using Dual-axis Confocal Microscopy and Wide-field Endoscopy
Steven Sensarn, PhD
September 19, 2012

Sodium Fluoride PET/CT: An Advanced Imaging Technique to Identify and Predict The Behavior of Painful Osseous Metastases For Early Intervention
Bhavya Shah, MD
September 19, 2012


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Improving Radiation Therapy for Moving Tumors
Sarah Geneser, PhD
June 20, 2012

T2 Weighted Imaging for Improved Lesion Characterization in Breast MRI
Catherine Moran, PhD
June 20, 2012


MR Guided Focused Ultrasound Surgery
Pejman Ghanouni, MD, PhD
March 7, 2012

In Line MRI-linac Configuration
Dragos E. Constantin
March 7, 2012


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