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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Cervical SPECT Camera for Parathyroid Imaging

Primary hyperparathyroidism characterized by one or more enlarged parathyroid glands has become one of the most common endocrine diseases in the world affecting about 1 per 1000 in the United States. Standard treatment is highly invasive exploratory neck surgery called Parathyroidectomy. The surgery has a notable mortality rate because of the close proximity to vital structures. The move to minimally invasive parathyroidectomy is hampered by the lack of high resolution pre-surgical imaging techniques that can accurately localize the parathyroid with respect to surrounding structures. We propose to develop a dedicated ultra-high resolution (~ 1 mm) and high sensitivity (10x conventional camera) cervical scintigraphic imaging device. It will be based on a multiple pinhole-camera SPECT system comprising a novel solid state CZT detector that offers the required performance. The overall system will be configured to fit around the neck and comfortably image a patient.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1981

Cervix-to-rectum measuring device in a radiation applicator for use in the treatment of cervical cancer

A cervix-to-rectum measuring device to be used in the treatment of cervical cancer is described. It includes a handle and a probe pivotably connected to the handle for insertion in the rectum. The measuring device further includes means for coupling the handle to an intrauterine radiation applicator when the latter is positioned in the uterine cervix and the probe is inserted in the rectum to pivot the handle about the probe. A gear is provided which is adapted to pivot with the probe. A pinion pivotably connected to the handle meshes with the gear. A pointer fixed to the pinion is displaced in response to the pivoting of the handle about the probe, and this displacement can be read from a scale on the handle, providing an indication of the cervix-to-rectum distance.

Fischell, D. R.↗
DOE OSTI2013

Treatment of Cervical Internal Carotid Artery Spontaneous Dissection with Pseudoaneurysm and Unilateral Lower Cranial Nerves Palsy by Two Silk Flow Diverters

Internal carotid artery (ICA) lesions in the parapharyngeal space (a dissection and a pseudoaneurysm) may present as isolated lower cranial nerves (IX, X, XI, and XII) palsy (Collet-Sicard syndrome). Some arteriopathies such as fibromuscular dysplasia and tortuosity make a vessel predisposed to dissection. Extreme vessel tortuosity makes the treatment by a stent graft impossible. Two Silk stents were used in a 46 year-old man with left lower cranial nerves (IX-XII) palsy for the treatment of left ICA spontaneous dissection with pseudoaneurysm. A follow-up angiogram 5 months later confirmed pseudoaneurysm thrombosis and patency of the left ICA. The patient recovered completely from the deficits.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Assessment of Organ Motion in Postoperative Endometrial and Cervical Cancer Patients Treated With Intensity-Modulated Radiation Therapy

Purpose: Intensity-modulated radiation therapy (IMRT) may be useful to reduce toxicity in gynecologic cancer patients requiring postoperative pelvic irradiation. This study was undertaken to quantify vaginal wall organ motion during the course of postoperative pelvic irradiation using pelvic IMRT. Methods and Materials: Twenty-two consecutive patients treated with postoperative pelvic IMRT on helical tomotherapy had fiducial markers placed at the vaginal apex prior to simulation then daily megavoltage computed tomography (CT) scans for positioning. The daily positions of the fiducials were registered and measured in reference to the initial CT scan to quantify the degree of vaginal wall organ motion during the entire course of therapy. Results: The total motion of the fiducials center of mass (COM) was a median of 5.8 mm (range, 0.6-20.2 mm), and 95% of all COM positions fell within 15.7 mm of their original position. Directional margins of 3.1 mm along the right-left axis, 9.5 mm along the superoinferior axis, and of 12.1 mm along the anteroposterior axis encompassed the vaginal fiducials in 95% of treatments. Mean organ deformation for all patients was 3.9 mm, (range, 0-27.5 mm; standard deviation, 3.1 mm), with significant distortions of greater than 10 mm in 17% of secondary image sets. Conclusions: These data suggest a planning target volume margin of 16 mm will account for maximal organ motion in the majority of gynecologic patients undergoing postoperative pelvic IMRT, and it may be possible to incorporate directional motion into the planning target volume margin.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Development of the M. D. Anderson Cancer Center Gynecologic Applicators for the Treatment of Cervical Cancer: Historical Analysis

Purpose: To provide historical background on the development and initial studies of the gynecological (gyn) applicators developed by Dr. Gilbert H. Fletcher, a radiation oncologist and chairperson from 1948 to 1981 of the department at the M.D. Anderson Hospital (MDAH) for Cancer Research in Houston, TX, and to acknowledge the previously unrecognized contribution that Dr. Leonard G. Grimmett, a radiation physicist and chairperson from 1949 to 1951 of the physics department at MDAH, made to the development of the gynecological applicators. Methods and Materials: We reviewed archival materials from the Historical Resource Center and from the Department of Radiation Physics at University of Texas M. D. Anderson Cancer Center, as well as contemporary published papers, to trace the history of the applicators. Conclusions: Dr. Fletcher's work was influenced by the work on gynecologic applicators in the 1940s in Europe, especially work done at the Royal Cancer Hospital in London. Those efforts influenced not only Dr. Fletcher's approach to the design of the applicators but also the methods used to perform in vivo measurements and determine the dose distribution. Much of the initial development of the dosimetry techniques and measurements at MDAH were carried out by Dr. Grimmett.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

MRI-based Preplanning Using CT and MRI Data Fusion in Patients With Cervical Cancer Treated With 3D-based Brachytherapy: Feasibility and Accuracy Study

Purpose: Magnetic resonance imaging (MRI)-assisted radiation treatment planning enables enhanced target contouring. The purpose of this study is to analyze the feasibility and accuracy of computed tomography (CT) and MRI data fusion for MRI-based treatment planning in an institution where an MRI scanner is not available in the radiotherapy department. Methods and Materials: The registration inaccuracy of applicators and soft tissue was assessed in 42 applications with CT/MRI data fusion. The absolute positional difference of the center of the applicators was measured in four different planes from the top of the tandem to the cervix. Any inaccuracy of registration of soft tissue in relation to the position of applicators was determined and dose-volume parameters for MRI preplans and for CT/MRI fusion plans with or without target and organs at risk (OAR) adaptation were evaluated. Results: We performed 6,132 measurements in 42 CT/MRI image fusions. Median absolute difference of the center of tandem on CT and MRI was 1.1 mm. Median distance between the center of the right ovoid on CT and MRI was 1.7 and 1.9 mm in the laterolateral and anteroposterior direction, respectively. Corresponding values for the left ovoid were 1.6 and 1.8 mm. Rotation of applicators was 3.1 Degree-Sign . Median absolute difference in position of applicators in relation to soft tissue was 1.93, 1.50, 1.05, and 0.84 mm in the respective transverse planes, and 1.17, 1.28, 1.27, and 1.17 mm in selected angular directions. The dosimetric parameters for organs at risk on CT/MRI fusion plans without OAR adaptation were significantly impaired whereas the target coverage was not influenced. Planning without target adaptation led to overdosing of the target volume, especially high-risk clinical target volume - D{sub 90} 88.2 vs. 83.1 (p < 0.05). Conclusions: MRI-based preplanning with consecutive CT/MRI data fusion can be safe and feasible, with an acceptable inaccuracy of soft tissue registration.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Magnetic Resonance Imaging (MRI) Markers for MRI-Guided High-Dose-Rate Brachytherapy: Novel Marker-Flange for Cervical Cancer and Marker Catheters for Prostate Cancer

Purpose: To present a novel marker-flange, addressing source-reconstruction uncertainties due to the artifacts of a titanium intracavitary applicator used for magnetic resonance imaging (MRI)-guided high-dose-rate (HDR) brachytherapy (BT); and to evaluate 7 different MRI marker agents used for interstitial prostate BT and intracavitary gynecologic HDR BT when treatment plans are guided by MRI. Methods and Materials: Seven MRI marker agents were analyzed: saline solution, Conray-60, copper sulfate (CuSO{sub 4}) (1.5 g/L), liquid vitamin E, fish oil, 1% agarose gel (1 g agarose powder per 100 mL distilled water), and a cobalt–chloride complex contrast (C4) (CoCl{sub 2}/glycine = 4:1). A plastic, ring-shaped marker-flange was designed and tested on both titanium and plastic applicators. Three separate phantoms were designed to test the marker-flange, interstitial catheters for prostate BT, and intracavitary catheters for gynecologic HDR BT. T1- and T2-weighted MRI were analyzed for all markers in each phantom and quantified as percentages compared with a 3% agarose gel background. The geometric accuracy of the MR signal for the marker-flange was measured using an MRI-CT fusion. Results: The CuSO{sub 4} and C4 markers on T1-weighted MRI and saline on T2-weighted MRI showed the highest signals. The marker-flange showed hyper-signals of >500% with CuSO{sub 4} and C4 on T1-weighted MRI and of >400% with saline on T2-weighted MRI on titanium applicators. On T1-weighted MRI, the MRI signal inaccuracies of marker-flanges were measured <2 mm, regardless of marker agents, and that of CuSO{sub 4} was 0.42 ± 0.14 mm. Conclusion: The use of interstitial/intracavitary markers for MRI-guided prostate/gynecologic BT was observed to be feasible, providing accurate source pathway reconstruction. The novel marker-flange can produce extremely intense, accurate signals, demonstrating its feasibility for gynecologic HDR BT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Radiosensitizing effect of gold nanoparticles in carbon ion irradiation of human cervical cancer cells

Noble metal nanoparticles have received considerable attention in biotechnology for their role in bio sensing due to surface plasmon resonance, medical diagnostics due to better imaging contrast and therapy. The radiosensitization effect of gold nanoparticles (AuNP) has been gaining popularity in radiation therapy of cancer cells. The better depth dose profile of energetic ion beam proves its superiority over gamma radiation for fighting against cancer. In the present work, the glucose capped gold nanoparticles (Glu-AuNP) were synthesised and internalized in the HeLa cells. Transmission electron microscopic analysis of ultrathin sections of Glu-AuNP treated HeLa cells confirmed the internalization of Glu-AuNPs. Control HeLa cells and Glu-AuNp treated HeLa cells were irradiated at different doses of 62 MeV 12C ion beam (LET - 290keV/{mu}m) at BIO beam line of using 15UD Pelletron accelerator at Inter University Accelerator Centre, New Delhi, India. The survival fraction was assessed by colony forming assay which revealed that the dose of carbon ion for 90% cell killing in Glu-AuNP treated HeLa cells and control HeLa cells are 2.3 and 3.2 Gy respectively. This observation shows {approx} 28% reduction of {sup 12}C{sup 6+} ion dose for Glu-AuNP treated HeLa cells as compared to control HeLa cells.

61 RADIATION PROTECTION AND DOSIMETRY↗