In vivo relaxation time measurements on a murine tumor model—Prolongation of T1 after photodynamic therapy

Liu, Y.H.; Hawk, Roger M.; Ramaprasad, S.

doi:10.1016/0730-725x(94)00107-e

Cited by 13 publications

(11 citation statements)

References 17 publications

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“…The increase in T, values were significant in all regions of the tumor area chosen in this study. These results are also consistent with our earlier studies on whole tumors studied on a 4.7T instrument (15).…”

Section: Relaxivity Valuessupporting

confidence: 83%

Magnetic Resonance Studies of Photosensitizers and Their Effect in Tumors

Ramaprasad¹

2004

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Public reporting burden for this collection of information is estimated to average 1 hour per response, Including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202. 4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 3. DATES COVERED (From -To) PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBERUniversity of Nebraska Medical Center Omaha, NE 68198-5100 SPONSORING I MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) U.S. Army Medical Research and Materiel Command Fort Detrick, Maryland 21702-5012 SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for Public Release; Distribution Unlimited SUPPLEMENTARY NOTES ABSTRACTIn this project we used specifically fluorine labeled photosensitizers which will be of utility in the treatment of breast cancer via photodynamic therapy(PDT). The accumulation of the photosensitizer in the tumor and the muscle were evaluated using noninvasive 19F spectroscopic modality in mice bearing RIF tumor. By determining the relative disposition of the sensitizer we can determine the best time to irradiate the tumor causing minimal damage to nearby healthy cells around the tumor. The absorption, distribution and elimination of the labeled sensitizer were determined using 19F spectroscopy of tumor models after administering a single dose of the sensitizer. The tumor regression was achieved by irradiating the tumor with an appropriate wavelength laser light. The process of tumor regression and the accompanying changes in the high energy phosphates and diffusion process were monitored by 31 P and I H MR studies. The 31 P MR studies performed before and after the use of 19F labeled PS(DOD2,DOD6) showed changes in the spectra and tumor regression was observed after PDT studies under fractionated laser doses. The corresponding nonlabeled compounds showed less significant 31 P spectral changes and lower tumor response following PDT. Soon there after an undergraduate level technician was hired and a year later a graduate level technician was hired to perform higher level data analysis involved in the project. The project did have ups and downs and the initial hurdle was that the 7T magnet could not be charged to the required field strength and hence was maintained at 4.7T while the ...

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Section: Relaxivity Valuessupporting

confidence: 83%

Magnetic Resonance Studies of Photosensitizers and Their Effect in Tumors

Ramaprasad¹

2004

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“…6 Third, in vivo 31 P nuclear magnetic resonance ͑NMR͒ has been used to monitor tumor metabolic status before and after the treatment of RIF-1 tumors 7,8 and mammary carcinoma. 9,10 During PDT treatment, significant decreases were observed for the nucleoside triphosphate concentrations, and tumor pH, while inorganic phosphate concentrations increased. 7 The NMR data revealed significant differences in the time course of highenergy phosphate levels in combined hyperthermia and photodynamic therapies.…”

Section: Introductionmentioning

confidence: 96%

Deformable and rigid registration of MRI and microPET images for photodynamic therapy of cancer in mice

et al. 2006

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We are investigating imaging techniques to study the tumor response to photodynamic therapy (PDT). Positron emission tomography (PET) can provide physiological and functional information. High-resolution magnetic resonance imaging (MRI) can provide anatomical and morphological changes. Image registration can combine MRI and PET images for improved tumor monitoring. In this study, we acquired high-resolution MRI and microPET 18F-fluorodeoxyglucose (FDG) images from C3H mice with RIF-1 tumors that were treated with Pc 4-based PDT. We developed two registration methods for this application. For registration of the whole mouse body, we used an automatic three-dimensional, normalized mutual information algorithm. For tumor registration, we developed a finite element model (FEM)-based deformable registration scheme. To assess the quality of whole body registration, we performed slice-by-slice review of both image volumes; manually segmented feature organs, such as the left and right kidneys and the bladder, in each slice; and computed the distance between corresponding centroids. Over 40 volume registration experiments were performed with MRI and microPET images. The distance between corresponding centroids of organs was 1.5 +/- 0.4 mm which is about 2 pixels of microPET images. The mean volume overlap ratios for tumors were 94.7% and 86.3% for the deformable and rigid registration methods, respectively. Registration of high-resolution MRI and microPET images combines anatomical and functional information of the tumors and provides a useful tool for evaluating photodynamic therapy.

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“…Gadolinium diethylenetriamene pentaacetate (DTPA) contrast-enhanced MRI was used to assess the boundary of PDT-induced tissue necrosis in a canine model [23] and in human patients [24]. Second, in vivo 31 P nuclear magnetic resonance (NMR) spectroscopy has been used to monitor tumor metabolic status before and after the treatment of RIF-1 tumors [25,26] and mammary carcinoma [27][28][29][30]. NMR data analysis revealed significant differences in the time course of changes in high energy phosphate levels in response to combined hyperthermia and photodynamic therapies [29].…”

Section: Introductionmentioning

confidence: 99%

High‐field magnetic resonance imaging of the response of human prostate cancer to Pc 4‐based photodynamic therapy in an animal model

et al. 2007

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Introduction-High-field magnetic resonance imaging (MRI) is an emerging technique that provides a powerful, non-invasive tool for in vivo studies of cancer therapy in animal models. Photodynamic therapy (PDT) is a relatively new treatment modality for prostate cancer, the second leading cause of cancer mortality in American males. The goal of this study was to evaluate the response of human prostate tumor cells growing as xenografts in athymic nude mice to Pc 4-sensitized PDT.

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In vivo relaxation time measurements on a murine tumor model—Prolongation of T1 after photodynamic therapy

Cited by 13 publications

References 17 publications

Magnetic Resonance Studies of Photosensitizers and Their Effect in Tumors

Magnetic Resonance Studies of Photosensitizers and Their Effect in Tumors

Deformable and rigid registration of MRI and microPET images for photodynamic therapy of cancer in mice

High‐field magnetic resonance imaging of the response of human prostate cancer to Pc 4‐based photodynamic therapy in an animal model

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