Software toolkit shapes models for personalized radionuclide therapy

June 11, 2013

External beam radiation treatment has long been manipulated into the unique shape of patients' tumors for personalized cancer care. Technology providing a means of patient-specific radionuclide drug therapies has not been standardized, as it has been limited to software that requires oncologists to manually define the areas of tumors. A new "phantom" model of the human form that can be deformed and reformed to match anatomy in a matter of hours using 3D graphic design software is being combined with a precision method for predicting how radionuclide therapies interact with tissues to determine the most effective cancer-killing dose for every patient.

"One-size-fits all therapy is not optimal for patients who could be getting personalized ," said Susan Kost, MS, principal author of the study from Vanderbilt University in Nashville, Tenn. "With individualized patient modeling we have an opportunity to offer more aggressive radionuclide therapy. Knowing a patient's drug kinetics and anatomy means we can give the possible while minimizing effects on normal tissue."

The geometric design technology used for these anthropomorphic models, created by Paul Segars, PhD, at Duke University, is called NURBS (non-uniform rational b-splines). With NURBS, anatomical volumes derived from computed tomography imaging data of patients' organs and body parts are sculpted, rotated and scaled to create a model within one to two hours. Once a model is made, it is used for treatment planning in conjunction with single photon emission computed tomography or positron , which—in most cases—use non-therapeutic imaging agents to mimic therapeutic radioactivity in the body. This allows physicians to extrapolate a precise dose, a process called dosimetry, via a 3D map representing projected dose absorption.

Ordinarily, dosimetry is performed by defining the structure and volume of tumors manually in 3D computer programs, known as tumor segmentation. However, this method can be labor intensive and may not provide dose information for normal tissue. In this study, patient-specific NURBS models serve as input in automated dosimetry calculations to factor anatomical data and radiopharmaceutical kinetics for I-131 radioimmunotherapy, specifically looking at the distribution of radioactive particles in the body as they seek out physiological processes of cancer cells and tissues. In action, tumor-tailored monoclonal antibodies are labeled with a potent dose of a radioisotope, and together they bind to receptors on the surface of cancer cells, effectively killing them and sparing nearby healthy cells.

"This research brings nuclear medicine therapy alongside therapy," Kost added. "Now each patient can receive his or her own therapy plan, leading to improved outcomes, better survival rates and less toxicity and harm to normal tissue in the body."

The NURBS phantom models are currently available for clinical use, and Kost expects the modeling toolkit to be used in a subsequent clinical trial conducted by Vanderbilt University for a tumor-targeted peptide receptor radionuclide therapy. A commercially viable version of the dosimetry software is scheduled for release to other cancer centers starting sometime next year.

Explore further: 'Scout scans' map the way in non-Hodgkin's lymphoma treatment

Related Stories

'Scout scans' map the way in non-Hodgkin's lymphoma treatment

June 7, 2010

According to a study presented at SNM's 57th Annual Meeting, molecular imaging can evaluate and optimize non-Hodgkin's lymphoma therapy with Zevalin, a front-line radioimmunotherapy drug that uses a dose of radioactive material ...

Dose analysis predicts non-Hodgkin lymphoma survival

June 11, 2013

Outcomes can be bleak for non-Hodgkin lymphoma (NHL), a cancer that develops in the white blood cells of the immune system. Accurate estimation of radiation absorbed dose in radioimmunotherapy (RIT) based on state-of-the-art ...

Recommended for you

Oxygen can impair cancer immunotherapy in mice

August 25, 2016

Researchers have identified a mechanism in mice by which anticancer immune responses are inhibited within the lungs, a common site of metastasis for many cancers. This mechanism involves oxygen inhibition of the anticancer ...

Stem cell propagation fuels cancer risk in different organs

August 25, 2016

The idea that stem cells - special cells that divide to repair and generate tissues - might be the major determinant of cancer risk has provoked great debate in the scientific community. Some researchers maintain that environmental ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.