Oldham Lab

Research

Research Overview

The lab pursues two main avenues of research.  The first involves developing and applying new methods of high resolution 3D dosimetry.  A range of uniquely capable state-of-the-art 3D dosimetry systems have been developed with funding support from the National Institute of Health.  These systems are currently being applied to a diverse range of challenges in both the clinical (radiation therapy) and research domains.  The second direction focuses on developing the new optical bio-imaging techniques of optical-computed-tomography (optical-CT), and optical-emission-computed-tomography (optical-ECT).  These techniques have the potential to provide uniquely useful information on biological processes in bulk tumor and tissue samples. Both of the avenues of research are briefly described below

High Resolution 3D Dosimetry:  In the last 5 years, the Duke 3D Dosimetry Lab has established itself as one of the leading 3D dosimetry groups in the world.  The Lab has received NIH R01 funding to develop optical imaging techniques for 3D dosimetry.  Key aims of the Lab include (i) elevating the state-of-the-art for verification of advanced and new radiation therapy treatments, (ii) developing powerful new 3D dosimetry tools for diverse applications including proton-therapy, micro-beam therapy, pre-clinical cancer research, and the nuclear industry. Our research has demonstrated that the PRESAGE/optical-CT 3D dosimetry system can achieve these aims.  The research involves a 3-party consortium combining expertise in 3D dosimetry (Duke) with clinical trials credentialing experience (Geoffery Ibbott at the RPC/MDACC), and radiochromic materials expertise (John Adamovics at Rider University).  Recent projects are highlighted in the table below, and include the first comprehensive 3D investigations of the accuracy of IMRT deliveries in a cohorts of patients. 

Project Description

Collaborators

Comment and Articles/Abstracts

Characterization and commissioning of brachytherapy sources in 3D

O Craciunescu,
J Adamson

Initial work focused on the HDR Iridium source [6].  More recently we participated in the commissioning of the new LDR Cs-137 sources.

A new Patient Specific QA protocol for 4D SBRT

FF Yin

There is currently no good way to verify SBRT dosimetry when treating moving tumors.  The DLOS/Presage system is uniquely suited to this challenge [7].

Radiosurgery and Small field dosimetry

Z Wang
J Chang,
 

The measurement of small field output factors and PDD is challenging for conventional dosimeters, and errors have caused patient harm in other centers.  Here we independently verified Duke commissioned values for the blue machine [8].  In another study we investigated the accuracy of TGN treatment [9].

Verification of the accuracy of Varian gating technology and treatment.

S Yoo

We investigate the accuracy of the Varian RPM system as implemented at Duke [10].

Investigating the accuracy of advanced treatments in cohorts of patients

S Das, F Yin
J Kirkpatrick,
J O’Daniel

The first such study on the accuracy of base-of-skull IMRT has been completed, and currently being written up.  Other studies are planned as a primary goal of the lab for other techniques such as RapidArc and IGRT [11].

Improving the effectiveness and quality of advanced RT credentialing tests for clinical trials.

Geoff Ibbott, PhD

Chief of Physics, MDAnderson Cancer Center

The lab has had a long and fruitful collaboration with the MD Anderson Cancer Center and the Radiological Physics Service.  A sequence of publications is laying strong foundations for enabling the first 3D credentialing tests [12, 13, 14, 15, 16].

Developing a 3D dosimetry system for Proton therapy

Indra Das, PhD
Chief of Physics at U. Indiana
Geoff Ibbot PhD

New dosimetry tools are urgently required which can verify complex Proton dose distributions.  This is challenging due to high-LET in the Bragg peak, where many dosimeters under-respond and are inaccurate.  We are investigating a new approach which shows promise [17, 18].

Commissioning a small animal irradiating system for pre-clinical research studies at Duke

David Kirsch, PhD
Shiva Das, PhD

The recently acquired small animal irradiator is a low E (225kV) machine with field sizes 1-40mm.  Determining outputs and PDD for these fields is very challenging with conventional dosimeters due to set-up errors.  Our recent work [19] showed how 3D techniques can be very useful and improved the accuracy of measurements

Developing re-useable 3D dosimeters, and true anthropomorphic 3D dosimetry phantoms

John Adamovics, PhD,  Rider University, NJ.

The lab has a long and fruitfull collaboration with Prof Adamovics, the inventor of Presage.  Preliminary studies show that both re-useable 3D dosimeters [20], and anthropomorphic dosimeters [21] are feasible.

In 2010 we hosted the 6th International Conference on 3D Radiation Dosimetry (IC3DDose) 

Conference Program
Conference Flier

Recent papers from our NIH work are available open-access from PubMed:

Optical Bio-imaging:  Separate from the work on 3D dosimetry, the lab also has a long-term collaboration with Dr Mark Dewhirst’s group at Duke, which is focused on novel techniques for optical bio-imaging.   Specifically, applying optical tomographic techniques to imaging unsectioned tissue samples [22-30].  The primary aim is to investigate and optimize the new techniques of optical-computed-tomography (optical-CT) and optical-emission-tomography (optical-ECT), and establish their capability as powerful new tools of pre-clinical cancer biology.  Optical-CT/ECT are the optical analogues of x-ray-CT and SPECT respectively.  In conjunction with new techniques for rendering bulk tissue samples transparent to visible light [24], optical-CT/ECT can yield unique data unattainable by other modalities.  Principally: high-spatial resolution (potentially 10-20µm), high contrast, precisely co-registered, three-dimensional (3D) images of the distribution of fluorescent reporter proteins and absorbing contrast agents in large un-sectioned tissue samples (up to ~8cc).  This capability is of significant interest to cancer researchers because it provides, for the first time, data similar to that obtained from influential window-chamber studies, but in much larger tumors.  Optical-CT/ECT have potential for very diverse application.  Our initial work builds on funded work in Dr Dewhirsts lab investigating novel therapeutics to reduce a critical cause of radiation and chemotherapy treatment failure: hypoxic-tumor resistance.  We aim to image the 3D distribution of vasculature, HIF-1 and viable tumor in much larger tumors than has been possible before.  Successful completion will establish optical-CT/ECT as powerful new tools of pre-clinical cancer biology, with diverse applicability, capable of providing unique data on key biological characteristics in larger tumors.  The 'proof of principle' is to evaluate novel therapeutics for hypoxic-tumor-resistance.  The results may help determine a new and effective therapeutic approach to this critical cause of radiation and chemotherapy treatment failure.  Two papers from this research collaboration were selected for Phys Med Biol Highlights Edition in 2008 [23] and 2010 [22], and one was short-listed for the Robert’s Prize [23] from the IOP. 

Optical-Biophysics: -- Illustrative multi-modal images from our Optical-CT/ECT system

 

 

 

 

 

 

Recent papers from our optical-CT/ECT work are found below: