Hans-S. Jans

University of Alberta | UAlberta · Department of Oncology

Objective The objective of the study is to demonstrate the feasibility of using [11C]-choline positron-emission tomography (PET)/CT to deliver helical tomotherapy (HT) to the prostate with a simultaneous integrated boost to dominant intraprostatic lesions as a biological target volume for dose escalation. Methods Eleven patients with intermediate-r...

6-Deoxy-6-[(18)F]fluoro-D-fructose (6-[(18)F]FDF) is a promising PET radiotracer for imaging GLUT5 in breast cancer. The present work describes GMP synthesis of 6-[(18)F]FDF in an automated synthesis unit (ASU) and dosimetry calculations to determine radiation doses in humans. GMP synthesis and dosimetry calculations are important prerequisites for...

The radiometal (64)Cu is now widely used in the development of diagnostic imaging agents for positron emission tomography (PET). The present study has led to the development and evaluation of a novel chelating agent for (64)Cu: the new monothiourea tripodal ligand 1-benzoyl-3-{6-[(bis-pyridin-2-ylmethyl-amino)-methyl]-pyridin-2-yl}-thiourea (MTUBo)...

The objective of the present study was to analyze, with relatively high sensitivity and specificity, uptake properties of [(11)C]-choline in prostate cancer patients by means of positron-emission tomography (pet)/computed tomography (ct) imaging using objectively defined pet parameters to test for statistically significant changes before, during, a...

The National Electrical Manufacturers Association (NEMA) standard NU 4-2008 for performance measurements of small-animal tomographs was recently published. Before this standard, there were no standard testing procedures for preclinical PET systems, and manufacturers could not provide clear specifications similar to those available for clinical syst...

Background: Tumour hypoxia is associated with increased metastasis, invasion, poor therapy response and prognosis. Most PET radiotracers developed and used for clinical hypoxia imaging belong to the 2-nitroimidazole family. Recently we have developed novel 2-nitroimidazole-derived PET radiotracer [18F]FBNA (N-(4-[18F]fluoro-benzyl)-2-(2-nitro-1H-i...

Theragnostic pairs of isotopes are used to infer radiation dosimetry for a therapeutic radiopharmaceutical from a diagnostic imaging study with the same tracer molecule labelled with an isotope better suited for the imaging task. We describe the transfer of radiation dosimetry from the diagnostic radioiodine isotope 123I, labelled for the hypoxia t...

Theranostic isotope pairs have gained recent clinical interest as they can be labeled to the same tracer and applied for diagnostic and therapeutic purposes. The goals of this study were to A) investigate cyclotron production of clinically relevant 133La activities using natural and isotopically enriched barium target material, B) compare fundament...

Introduction Radiolabeled peptides play a central role in nuclear medicine as radiotheranostics for targeted imaging and therapy of cancer. We have recently proposed the use of metabolically stabilized GRPR antagonist BBN2 for radiolabeling with ¹⁸F and ⁶⁸Ga and subsequent PET imaging of GRPRs in prostate cancer. The present work studied the impact...

The present study used [18F]FDG-PET to study glucose metabolism and tumor responses for thyroid cancer xenografts expressing the glycolytic pathway modulators platelet-derived growth factor receptor (PDGFR) and BRAFV600E. PET data were correlated with immunohistochemistry staining and kinetic analysis for facilitative glucose transporter 1 (GLUT1)...

Purpose: The decay characteristics of radionuclides in PET studies can impact image reconstruction. 44gSc has been the topic of recent research due to potential theranostic applications and is a promising radiometal for PET imaging. In this study, the reconstructed images from phantom measurements with scandium in a small-animal PET scanner are co...

Purpose: The response of well-type ionization chambers used e.g. in brachytherapy and nuclear medicine depends on the location of the source. In cases where the source length is variable (typically in nuclear medicine), it is also dependent on length of the source. Here, the combined effect on chamber sensitivity of both, source position and lengt...

Purpose: Pharmacokinetic (PK) data are generally derived from blood samples withdrawn serially over a defined period after dosing. In small animals, blood sampling after dosing presents technical difficulties, particularly when short time intervals and frequent sampling are required. Positron emission tomography (PET) is a non-invasive functional...

Purpose: Pharmacokinetic (PK) data are generally derived from blood samples withdrawn serially over a defined period after dosing. In small animals, blood sampling after dosing presents technical difficulties, particularly when short time intervals and frequent sampling are required. Positron emission tomography (PET) is a non-invasive functional...

There is a wide diversity of production methods for radionuclides. With these, intensive calculations are often required to characterize the different radionuclide production strategies and to determine optimal irradiation parameters. These calculations are essential for predicting the yield and radionuclidic purity of the resulting product. In thi...

Purpose: To present and evaluate an ion chamber-based method for the cross-calibration between sites of activity measurements of unsealed radionuclides. Notably, the method allows direct comparison of short lived (i.e., clinically used) radioisotopes and the cross-calibration of radionuclide activity meters (also known as “dose calibrators”). Meth...

Purpose:To estimate the total dosimetric uncertainty at the tumor apex for ocular brachytherapy treatments delivered using 16 mm Collaborative Ocular Melanoma Study (COMS) and Super9 plaques loaded with 125I seeds in order to determine the size of the apex margin that would be required to ensure adequate dosimetric coverage of the tumor. Methods:Th...

Background: Prostate-specific membrane antigen (PSMA) is frequently overexpressed and upregulated in prostate cancer. To date, various (18)F- and (68)Ga-labeled urea-based radiotracers for PET imaging of PSMA have been developed and entered clinical trials. Here, we describe an automated synthesis of [(18)F]DCFPyL via direct radiofluorination and...

To determine the effect of geometric uncertainties in the seed positions in a COMS eye plaque on the central axis (CAX) dose. A Silastic insert was placed into a photopolymer 3D printed 16 mm COMS plaque, which was then positioned onto a custom-designed PMMA eye phantom. High resolution 3D images were acquired of the setup using a Siemens Inveon mi...

The multitargeting tyrosine kinase inhibitor (TKI) sunitinib is currently the first-line drug therapy for metastasizing renal cell carcinoma (RCC). TKIs have profound effects on tumor angiogenesis, leading to modifications of the tumor microenvironment. The goal of this study was to determine whether these treatment-induced changes can be detected...

In this work, a class of non-negative matrix factorization (NMF) technique known as alternating non-negative least squares, combined with the projected gradient method, is used to analyze twenty-five [11C]-DTBZ dynamic PET/CT brain data. For each subject, a two-factor model is assumed and two factors representing the striatum (factor 1) and the non...

Purpose To compare the radiation dose to normal organs from the radio‐iodinated, hypoxia‐binding radiosensitizer iodoazomycin arabinoside (IAZA) for three different isotopes of iodine. Methods Dosimety studies with normal volunteers had been carried out with [ ¹²³ I]IAZA, a drug binding selectively to hypoxic sites. Two other isotopes of iodine, ¹...

Tumor volume delineation plays a critical role in radiation treatment planning and simulation. Inaccurately defined target volume may lead to overdosing of normal structures surrounding the tumor, while potentially underdosing cancerous tissue. Conventional 3-dimensional tumor segmentation methods ignore the temporal information present in dynamic...

Noise levels observed in positron emission tomography (PET) images complicate their geometric interpretation. Post-processing techniques aimed at noise reduction may be employed to overcome this problem. The detailed characteristics of the noise affecting PET images are, however, often not well known. Typically, it is assumed that overall the noise...

Abstract Several F-18-labeled 2-nitroimidazole (azomycin) derivatives have been proposed for imaging hypoxia using positron emission tomography (PET). Their cell penetration is based on passive diffusion, which limits their intracellular concentration maxima. The purpose of this study was to investigate the uptake of N-(2-[(18)F]fluoro-3-(6-O-gluco...

Purpose: To apply factor analysis technique to a sequence of 11C‐DTBZ dynamic PET images to healthy and diseased subjects in order to extract factor curves (or time activity curves) and associated factor images and develop a metric to detect extent of Parkinsonˈs disease. Methods: Philips Gemini (C) PET/CT scanner (with 4mm isotropic voxels) is use...

Purpose: To investigate the scatter dose received by a CT?scanner operator from walls and ceiling as a function of the height of the shielding barrier between the operator and the scanner. To compare Monte Carlo(MC) simulated data with measurement. Methods: MC simulations were performed, using the Penelope algorithm. The CTscanner and a typical, le...

Introduction: Several clinical studies have shown low or no expression of GLUT1 in breast cancer patients, which may account for the low clinical specificity and sensitivity of 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) used in positron emission tomography (PET). Therefore, it has been proposed that other tumor characteristics such as the high...

(18)F-3'-Deoxy-3'-fluorothymidine ((18)F-FLT) is a PET tracer that accumulates in proliferating tissues. The current study was undertaken to determine whether equilibrative nucleoside transporter 1 (ENT1) is important for (18)F-FLT uptake in normal tissues and tumors. ENT1-knockout (ENT1(-/-)) mice were generated and compared with wild-type (ENT1(+...

Interest has been growing in recent years in the development of radiation treatment planning (RTP) techniques based solely on magnetic resonance (MR) images. However, it is recognized that MR images suffer from scanner‐related and object‐induced distortions that may lead to an incorrect placement of anatomical structures. This subsequently may resu...

The aim of this study is to develop a magnetic resonance imaging (MRI)-based treatment planning procedure for intracranial lesions. The method relies on (a) distortion correction of raw magnetic resonance (MR) images by using an adaptive thresholding and iterative technique, (b) autosegmentation of head structures relevant to dosimetric calculation...

At Cross Cancer Institute, we are investigating a novel MRI‐linac system consisting of a bi‐planar 0.2 T permanent magnet coupled with a 6 MV Linac. The system can freely revolve axially around the patient to deliver dose from any desired angle. For such a system, the radiation treatment planning procedure is expected to rely on the MR images only,...

Post-implant dosimetry for permanent prostate brachytherapy is typically performed using computed tomography (CT) images, for which the clear visualization of soft tissue structures is problematic. Registration of CT and magnetic resonance (MR) image volumes can improve the definition of all structures of interest (soft tissues, bones, and seeds) i...

Post‐implant dosimetry for permanent prostate brachytherapy is typically performed using computed tomography (CT) images, for which the clear visualization of soft tissue structures is problematic. Registration of CT and magnetic resonance (MR) image volumes can improve the definition of all structures of interest (soft tissues, bones, and seeds) i...

Magnetic Resonance Imaging is the imaging modality of choice for target volume delineation required by radiotherapy planning (RTP) due to its superior soft‐tissue contrast. However, MRimages are affected by distortions that alter the imagespatial accuracy which is crucial for RTP. In the present work, we investigate a complete 3D phantom‐based prot...

Patient setup errors in external beam radiation therapy are a cause for differences between planned dose distribution and the one delivered to the patient. A changed dose distribution results in a changed tissue response, expressed as tumor control probability (TCP) and normal tissue complication probability (NTCP). A method was developed to calcul...

Purpose: The purpose of this study is to develop a complete treatment planning procedure for radiotherapy of brain lesions based solely on magnetic resonance imaging. Method and Materials: The MR‐based treatment planning procedure relies on converting the MR images into CT‐like images by assigning electron density information to organ structures (i...

Purpose: To implement and validate a 2D‐3D registration method for determining 3D patient position in external beam radiotherapy using orthogonal EPIDimages and megavoltage digitally reconstructedradiographs (MDRRs). To test the methods dependence on cost function, image pre‐processing and parameter space sample density, and determine the dependenc...

Reproducible positioning of the patient during fractionated external beam radiation therapy is imperative to ensure that the delivered dose distribution matches the planned one. In this paper, we expand on a 2D-3D image registration method to verify a patient's setup in three dimensions (rotations and translations) using orthogonal portal images an...

"A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements of the degree of Master of Science in Medical Physics, Department of Physics." Thesis (M.Sc.)--University of Alberta, Spring 2006. Includes bibliographical references.

Purpose. The aim of this work is to develop a complete treatment planning procedure for radiation therapy of intracranial lesions based solely on 3T magnetic resonance imaging (MRI), i.e. MRI simulation. Methods. The proposed 3T MR-based radiotherapy treatment planning procedure consists of converting the MR images into CT-like images by assigning...

Cd-arachidat in the form of Langmuir-Blodgett films and thick photoresist layers of AZ5412H have been exposed to 15N-ion beams. The physico-chemical state of these targets as a function of the 15N fluence has been monitored by the 15N nuclear reaction with the respective H component. In this way, radiolytic changes in H distribution and bonding hav...

A near-crisis is looming in the quest for a proper understanding of the role of hydrogen in diamond-this is increasingly appreciated as the key to the evident role of hydrogen in the growth of chemical vapour deposition (CVD) diamond, to the geochemical history and meaning of hydrogen in natural diamond, and finally to the effect of hydrogen in dia...

Diamond single crystals of , and orientation have been chemically treated in order to prepare monolayer (ML) coverages of 1H. Subsequently, sample surface areas of about 0.1 cm2 have been exposed to a 15N beam of 30 nA at the resonant-reaction energy of 6.385 MeV. The resulting 4.4 MeV gamma rays have been detected by a 10 in × 10 in NaI(Tl) crysta...

We have measured the linewidths of the 15N resonant nuclear reaction at 6.38 MeV on H bearing 1 to 10 nm thin films. By comparing the full width at half maximum values of the same film obtained by incident nitrogen ions of charge states 2 + and 3 + we have found evidence that the charge equilibration process takes place in less than 10 nm. This fea...