[Silicosis callosities or bronchial carcinoma: on the problem of functional differentiation using FDG-PET].
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Callosities↗
Biomedical subjects
C M Kirsch
Publications and source records attributed to C M Kirsch.
[Positive presentation of a localized neuroblastoma in skeletal scintigraphy].
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3-Iodobenzylguanidine↗
[Influence of single-photon emission scan duration measured with the ECAT ART PET scanner].
AIM: The aim was to study the influence of single-photon-transmission scan duration in 3D-PET on the quantitative values of attenuation coefficients and noise in transmission images and of activity concentrations and noise in attenuation corrected emission images of thorax phantom- and patient data. METHOD AND MATERIAL: Using dual collimated Cs-137 singles transmission sources (E gamma = 662 KeV, A = 2* 614 MBq) on an ECAT ART tomograph series of transmission scans of a thorax phantom were acquired pre- and post-injection of 18F. 17 patients underwent two transmission scans. The scan time of the short transmission was chosen according to the results of the phantom studies (noise of Poisson statistics less than 4%). Transmission and attenuation corrected emission images were evaluated with respect to estimated linear attenuation coefficients, noise and specific activities in organs. RESULTS: The phantom studies reveal little variation of the estimated linear attenuation coefficients as a function of scan duration. The estimates of the attenuation coefficients are found to be 1% lower than the expected values for pre- and up to 6.5% lower for post-injection transmissions. The noise level in the transmission images increases as expected for Poisson data. The noise level in the attenuation corrected emission images shows only little increase with decreasing transmission scan time whereas it is strongly influenced by a variation of emission scan time. In patient studies, less than 3% difference was found in the estimated linear attenuation coefficients as well as in the activity concentrations between short (pre or post-injection) and long transmission scans. The noise levels in transmission and emission images are 1% (pre-injection) and 4% (post-injection) higher for short transmission scans. CONCLUSION: Due to the high photon flux, single photon transmission offers good clinical performance with significantly reduced transmission scan durations (< 2 min/bed in pre-, < 4 min/bed in post-injection transmission).
Aged↗
[Radiation exposure to patients caused by single-photon transmission measurement in PET].
AIM: The aim of the study was the determination of the radiation exposure to the patient caused by single-photon transmission measurement for 3D whole-body PET. MATERIAL AND METHOD: Single-photon-transmission measurement is performed using two Cs-137 point-sources (E gamma = 662 keV, A = 2*614 MBq) on a 3D PET scanner (ECAT ART). During a simulation of a whole body transmission scan (axial length: 75 cm, 6 contigous bed positions) dose measurements with thermoluminescent dosimeters were carried out using a thorax and an abdomen phantom. Following the guidelines of the ICRU report No. 60 an estimation of the effective dose caused by a single-photon transmission measurement was calculated. RESULTS: For a total acquisition time of 360 min (6 beds with an acquisition time of 60 min per bed) the absorbed doses amounted to: surface (xyphoid) 189 microGy, heart 196 microGy, lungs 234 microGy, vertebra 240 microGy, liver 204 microGy, gonads 205 microGy, thyroid 249 microGy and bladder 185 microGy resulting in a conversion factor of 1.7*10(-4) mSv/(h*MBq). The estimation of the effective dose for a patient's transmission (acquisition time of 3.2 min per bed) yields a value of 11 microSv. An estimation of the ratio of the conversion factors for transmission measurements in single-photon- and in coincidence mode (two Ge-68/Ga-68 rod sources of 40 MBq each), respectively, resulted in a value of 0.18. The comparison of the effective doses caused by single-photon transmission and by emission measurement (injection of 250 MBq of FDG) yields a ratio of 2.3*10(-3). CONCLUSION: The radiation exposure of the patient caused by the transmission measurement for 3D whole-body-PET can be neglected. In comparison with the coincidence-transmission using uncollimated line sources of low activity the radiation exposure is still reduced using single photon trans-mission with collimated point sources of high activity.
Computer Simulation↗
18F-deoxyglucose positron emission tomography (FDG-PET) for the planning of radiotherapy in lung cancer: high impact in patients with atelectasis.
PURPOSE: 18F-deoxyglucose positron emission tomography (FDG-PET) is increasingly applied in the staging of lung cancer (LC). This study analyzes the potential contribution of PET in radiotherapy planning for LC with special respect to tumor-associated atelectasis. METHODS AND MATERIALS: Thirty-four patients with histologically confirmed LC, who had been examined by PET during pretreatment staging, were included. All were irradiated after CT-based therapy planning with anterior/posterior (AP) portals encompassing the primary tumor and the mediastinum (CT portals, CP). The result of the PET examination was unknown in treatment planning. In retrospect, a PET portal (PP) was delineated and compared with the CP. RESULTS: In 12/34 cases, the shape and/or size of the portals were changed, primarily (n = 10) the size of the fields was reduced. The median area of CP was 182 cm2 versus 167 cm2 of PP. Seventeen of 34 patients had dys- or atelectasis caused by a central primary tumor. In these cases, differences between CP and PP were significantly more frequent than in the other patients (8/17 vs. 3/17, p = 0.03). CONCLUSION: In this retrospective analysis, the information provided by FDG-PET would have contributed to a substantial reduction of the size of radiotherapy portals. This applies particularly for patients with tumor-associated dys- or atelectasis.
Carcinoma, Non-Small-Cell Lung↗
[Brain metastases of lung cancer: diagnostic accuracy of positron emission tomography with fluorodeoxyglucose (FDG-PET)].
The value of FDG-PET in oncology is currently investigated in clinical studies. There is only limited information on the usefulness of FDG-PET in the evaluation of distant metastases of lung cancer. The purpose of the present prospective investigation was to determine the diagnostic accuracy of FDG-PET in the detection of brain metastases of lung cancer. After intravenous injection of 220 +/- 50 MBq F-18-deoxyglucose PET acquisition was carried out using an ECAT ART scanner (CTI Siemens). Images were reconstructed using a filtered backprojection with a Hanning filter. PET data were analyzed by visual interpretation of coronal, sagittal and transversal slices. PET scans were interpreted by two experienced nuclear medicine physicians without prior knowledge of the results of other imaging studies or clinical data. Between March 1997 and July 1998 whole-body PET was performed in 417 patients with suspected lung cancer. 402 patients were used for statistical analysis. Based on conventional brain imaging with CT (occasionally MRI), brain metastases were suspected in 17 patients (prevalence 4.2%). For FDG-PET alone, sensitivity was 82% (14/17) and specificity 38% (14/37). Therefore, diagnostic accuracy of FDG-PET in detection of brain metastases was 93.5%. The low specificity of FDG-PET can be explained by reduced tracer uptake mainly due to brain infarction or vascular encephalopathy in this group of elderly patients. Our results indicate that due to its low specificity FDG-PET is not useful for the evaluation of brain metastases in the primary staging of patients with lung cancer.
Adult↗
Evaluation of l-3-[123I]iodo-alpha-methyltyrosine SPET and [18F]fluorodeoxyglucose PET in the detection and grading of recurrences in patients pretreated for gliomas at follow-up: a comparative study with stereotactic biopsy.
Based on the results of stereotactic biopsy, we evaluated in a prospective fashion the efficiency of l-3-[123I]iodo-alpha-methyltyrosine-single-photon emission tomography (SPET) and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the detection and grading of recurrences in patients previously treated for gliomas. The patient population comprised 30 individuals, nine with astrocytomas of grade II, ten with astrocytomas of grade IV, three with oligoastrocytomas of grade II, six with oligodendrogliomas of grade II and two with anaplastic oligodendrogliomas of grade III) suspected of recurrence and scheduled for further treatment. IMT SPET data were acquired using either by dual-or a triple-headed SPET camera, Multispect 2/3. FDG uptake was measured with an ECAT ART PET camera. Two independent observers classified PET and SPET images as positive or negative for tumour tissue. Uptake of FDG and IMT was evaluated visually and, in the case of IMT, also quantitatively by calculating the ratios between tracer accumulation in the lesion and the unaffected contralateral regions of reference using the region of interest (ROI) technique. The PET and SPET results were compared with the histopathological findings obtained either by stereotactic biopsy or in one case by open surgery. Glucose metabolism and amino acid uptake of recurrences of brain tumours as assessed by FDG-PET and IMT-SPET correlated highly with the histopathological findings. Based on the histopathological data, FDG-PET and IMT-SPET findings confirmed recurrence in all cases of high-grade gliomas (IV). A difference could be demonstrated in low-grade (II-III) tumour recurrences. True-positive IMT-SPET results were found in 86% of grade III and 75% of grade II recurrences, whereas FDG-PET yielded a sensitivity of 71% in tumours of grade III and 50% in those of grade II. With respect to the grade of malignancy of brain tumours at recurrence, IMT-SPET, in contrast to FDG-PET, does not permit adequate in vivo grading of non-mixed brain tumours of astrocytic or oligodendroglial origin. However, in this study FDG-PET did not permit discrimination between upgrading of low-grade oligoastrocytomas (II) into anaplastic oligodendrogliomas (III) and upgrading into glioblastomas (IV) The results of this study indicate that FDG-PET and IMT-SPET are equivalent to stereotactic biopsy in their ability to identify high-grade tumours at recurrence. IMT-SPET proved to be superior to FDG-PET in confirming low-grade recurrences. In the case of suspected progression of the grade of malignancy in ordinary gliomas, FDG-PET correlated significantly with the histopathological grading, whereas IMT-SPET did not. However, tumour grading by FDG-PET has a limitation in mixed brain tumours in that it is not possible to discriminate between progression of the oligo- versus the astrocytic tumour entity. In this case histopathological evaluation of the tumour grade remains necessary.
Adult↗
Monoclonal antibody MAb-170 for immunoscintigraphic detection of ovarian tumors.
OBJECTIVE: The technetium Tc 99m-labeled monoclonal antibody MAb-170 was designed for diagnostic use in patients with gynecologic adenocarcinoma. Our investigation was initiated to verify its usefulness for radioimmunoscintigraphy of ovarian tumors. STUDY DESIGN: Most of the 82 patients participating in this study underwent immunoscintigraphy before first-look surgery. RESULTS: Radioimmunoscintigraphy recognized 36 of 41 patients with adenocarcinoma of the ovaries, corresponding to an overall sensitivity of 88%. Specificity was 90% (38/42). The calculation of accuracy gave a result of 89% (74/83). Of 110 known lesions, 92 were visualized successfully; thus the local-regional sensitivity was 84%. Of 160 benign tumor sites, 154 showed no evidence of tracer accumulation, corresponding to a local-regional specificity of 96%. The smallest lesion visualized was an adenocarcinoma of the corpus uteri with a diameter of 1.5 cm. CONCLUSION: The monoclonal antibody MAb-170 is a promising radiopharmaceutical for immunoscintigraphy of ovarian adenocarcinoma.
Adenocarcinoma↗
Influence of right ventricular stimulation site on left ventricular function in atrial synchronous ventricular pacing.
OBJECTIVES: The study investigates the correlation between left ventricular function and QRS duration obtained by alternate right ventricular pacing sites. BACKGROUND: 1. Right ventricular apical pacing is associated with alterations of left ventricular contraction sequence. 2. A stimulation producing narrow QRS complexes is supposed to provide for better left ventricular contraction patterns. METHODS: Fourteen patients with third degree AV block received one ventricular pacing lead in apical position. The alternate lead was attached to that site on the septum that produced the smallest QRS complex as measured from the earliest to the last deflection in any of the orthogonal Frank leads (xyz). During atrial synchronous ventricular pacing, the AV delay was optimized individually and for each stimulation site using mitral valve doppler or impedance cardiography. By radionuclide ventriculography, the phase distribution histogram of left ventricular contraction was evaluated as area under the curve (AuC); systolic function was determined as ejection fraction (EF) and as absolute ejected counts (EC) in random order. The difference (delta) in QRS duration between apical and septal stimulation (deltaxyz) was correlated with the difference in phase distribution (deltaAuC) and ejection parameters (deltaEF, deltaEC). RESULTS: QRS duration was shorter with septal than with apical pacing in 9 out of 14 patients (64%); it was longer in 4 (29%), and no difference was seen in 1 patient. There was a significant positive correlation between the change in QRS duration (deltaxvz) and phase distribution (deltaAuC: r = 0.66393, p = 0.010) and a significant negative correlation to systolic function (deltaEF: r = 0.70931, p = 0.004; deltaEC: r = 0.74368, p = 0.002). CONCLUSIONS: In atrial synchronous right ventricular pacing, if the AV delay is adapted individually, decreased QRS duration obtained by alternate pacing sites is significantly correlated with homogenization of left ventricular contraction and with increased systolic function in acute tests.
Aged↗
Airway coccidioidomycosis--report of cases and review.
Infection due to Coccidioides immitis usually begins in the lungs. Despite the initial pulmonary portal of entry, endotracheal and endobronchial coccidioidomycosis has rarely been described. Since the introduction of fiberoptic bronchoscopy and the AIDS epidemic, more C. immitis lesions of the large airways have been noted. We present data on 38 cases of coccidioidomycosis of the airways, including 6 cases detailed from our own experience and 32 from the literature. Direct infection of the airways (28 cases) is a more common mechanism of airways disease than is erosion into the airways from a lymph node (5 cases). Bronchoscopic findings vary and may show mucosal involvement or intrinsic obstruction. Endotracheal and endobronchial disease is not a self-limited disease and requires antifungal therapy. Disseminated disease in these patients is common. Coccidioidomycosis must be considered in the differential diagnosis of airway pathology.
Adult↗
Improved labelling of no-carrier-added 123I-MIBG and preliminary clinical evaluation in patients with ventricular arrhythmias.
Meta-[123I]iodobenzylguanidine (123I-MIBG) is currently used to assess myocardial sympathetic innervation by single photon emission tomography (SPET). In recent studies, an enhanced cardiac uptake of 123I-MIBG with high specific activity has been reported, suggesting the clinical potential of no-carrier-added (n.c.a.) 123I-MIBG in the assessment of abnormalities in cardiac sympathetic function. This paper describes the preparation of n.c.a. 123I-MIBG by non-isotopic Cu(I)-assisted [123I]iododebromination and by [123I]iododestannylation, both resulting in n.c.a. 123I-MIBG with radiochemical yields of 88 +/- 6% and high specific activity (> or = 6.3 TBq.mumol-1) in a total synthesis time of less than 50 min. The diagnostic potential of n.c.a. 123I-MIBG (> 6.3 TBq.mumol-1) was studied in 13 patients (nine patients with malignant ventricular arrhythmias and four patients suspected of phaeochromocytoma) and compared to commercial 123I-MIBG (approximately 75 MBq.mumol-1) using a dual-headed SPET camera (MULTISPECT II). High specific activity results in higher 123I-MIBG uptake in the heart and in the liver in all patients. The calculated heart-to-lung and heart-to-liver count ratios 4.5 h post-injection increased by 22 +/- 6% and 10 +/- 5% with n.c.a. 123I-MIBG compared to commercial 123I-MIBG respectively. In contrast, no significant correlation between the specific activity of 123I-MIBG and lung uptake could be established in this study. Analysis of radioactivity in blood after the intravenous injection of n.c.a. and commercially available 123I-MIBG showed an initial rapid clearance of radioactivity from blood, followed by a plateau from 60 min onwards. Within the first 24 h, more than 85% of the plasma activity was unchanged 123I-MIBG. The free 123I-iodide concentration determined 24 h post-injection was 2 +/- 1% with commercial 123I-MIBG and 3 +/- 2% with n.c.a. 123I-MIBG. In conclusion, the results of this investigation indicate that n.c.a. 123I-MIBG is a promising clinical tool for imaging myocardial sympathetic dysfunction by SPET. High specific activity n.c.a. 123I-MIBG can now be prepared by simple one-step methods giving high radiochemical yields and high purity suitable for clinical application. This encourages the further clinical validation of n.c.a. 123I-MIBG on a large scale.
3-Iodobenzylguanidine↗
Pneumoparotid due to spirometry.
Pneumoparotid has been described in patients who generate increased intraoral pressures when playing wind instruments, while coughing, and when undergoing dental work. Some patients have intentionally created pneumoparotid to avoid duties at school or in the military, or to gain attention. We describe a patient who developed pneumoparotid during pulmonary function testing. The diagnosis of pneumoparotid depends on a suggestive clinical situation and glandular swelling with or without crepitus. Observation of aerated saliva per Stensen's duct or air in the parotid duct and/or gland by any imaging study is diagnostic if infection with a gas-forming organism can be reasonably excluded. No specific treatment is required, other than the avoidance of predisposing activities.
Adult↗
A 60-year-old man with a left upper lobe mass and hemoptysis.
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Actinomyces↗
[Radiation exposure of the patient caused by transmission measurement for myocardial perfusion SPECT].
AIM: The aim was the determination of the radiation exposure to the patient caused by the transmission measurement for myocardial perfusion SPECT. METHOD AND MATERIAL: Beside the emission measurement (Tc-99m-MIBI, A = 500 MBq) the myocardial perfusion SPECT simultaneously includes a transmission measurement using a Am-241-line source (A = 5550 MBq). During a simulation of the myocardial perfusion SPECT (without Tc-99m-MIBI) dose measurements with thermoluminescent dosimeters were carried out using a thorax phantom. RESULTS: For an acquisition time of 20 min the absorbed doses amounted to: surface (xyphoid) 30 microGy, heart 25 microGy, lung 14 microGy, second thoracic vertebra 16 microGy, upper anterior mediastinum 16 microGy, liver 0 microGy. An estimation of the ratio of the effective doses caused by the transmission and the emission measurement of 3.6 x 10(-3) and 4.1 mSv, respectively, resulted in a value of 9 x 10(-4). CONCLUSION: The radiation exposure of the patient caused by the transmission measurement can be neglected, and is therefore not a limiting factor regarding the general application of transmission measurement for clinical myocardial perfusion SPECT.
Heart↗
[Guidelines for gallium scintigraphy in malignant diseases].
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Gallium Radioisotopes↗
[A simple and rapid routine preparation of no-carrier added meta-I-123- and I-131-iodobenzylguanidine (I-123-MIBG and I-131-MIBG) for clinical nuclear medicine applications].
AIM: Low specific activity meta-iodobenzylguanidine (I-123/I-131-MIBG) is currently used in the assessment of abnormalities in the myocardial neuroadrenergic function as well as in the management of neuroendocrine tumors. In recent studies an enhanced cardiac and tumor uptake were reported by the use of high specific activity radiopharmazeuticals, suggesting a potential clinical benefit of no-carrier-added (n.c.a.) I-123/I-131-MIBG. In this paper we describe a simple and improved preparation of I-123-MIBG and I-131-MIBG for routine clinical application, feasible in any nuclear medicine department. METHODS: N.c.a I-123-MIBG and n.c.a. I-131-MIBG were prepared by Cu(I)-assisted [I-123/I-131]iodo-debromination at 170-175 degrees C with 86 +/- 6% and 80 +/- 10% radiochemical yield respectively and high specific activity (> or = 4.3 TBq/mumol and > or = 0.21 TBq/mumol), starting from meta-bromobenzylguanidine (MBBG). The total time of synthesis including the HPLC purification and the preparation of the injectable solution was less than 60 min. RESULTS: Neither rechromatography by HPLC nor TLC gave any indication of disintegration products in the injection solution up to 8 h after preparation. Moreover, biological testings confirmed that the buffered and sterile-filtered n.c.a. I-123-MIBG and n.c.a. I-131-MIBG solutions are isotonic, sterile and apyrogenic and thus suitable as injectable solutions for clinical use. CONCLUSION: High specific activity I-123-MIBG and I-131-MIBG could now be prepared by a simple one-step reaction giving rise to high radiochemical yields and high purity for a widespread clinical applications. Therefore, this encourages clinical validations on a large scale to answer the question of whether n.c.a. I-123-MIBG and I-131-MIBG could play an important role in the assessment of the myocardial sympathetic nervous dysfunction as well as in the diagnosis and therapy of neuroendocrine tumors.
3-Iodobenzylguanidine↗
[Contribution of nuclear medicine to the diagnosis of recurrent brain tumors and cerebral radionecrosis].
The evaluation of brain tumor recurrence and therapy-induced benign changes following surgery and/or irradiation is a diagnostic challenge for imaging methods based on either morphology (cCT/MRI) or function (SPECT/PET). Current literature and the present data of our own patients demonstrate the diagnostic efficiency of IMT-SPECT and FDG-PET in the detection of recurrence and in-vivo grading. Thirty-nine patients suspected of brain tumor recurrence at follow-up were studied by FDG-PET and IMT-SPECT. Thirty-four of 39 patients showed recurrences; in 12 cases even a change in the grade of malignancy was observed. All high-grade recurrences could be confirmed by either methods. IMT-SPECT showed a higher sensitivity in detecting low-grade tumors at recurrence. In contrast to IMT-SPECT, FDG-PET supports sufficient in-vivo grading. Both methods can be used to differentiate between tumor recurrence and radionecrosis. In conclusion the results of our study demonstrate the efficiency of IMT-SPECT and FDG-PET in confirming recurrences and determining the actual tumor grade.
Adult↗
123I-MSP and F[11C]MSP: new selective 5-HT2A receptor radiopharmaceuticals for in vivo studies of neuronal 5-HT2 serotonin receptors. Synthesis, in vitro binding study with unlabelled analogues and preliminary in vivo evaluation in mice.
In vitro binding study on bovine brain membranes using [3H]SCH23390, [3H]spiperone, [3H]prazosin and [3H]RP62203 as radioligands (for D1, D2, alpha1 and 5-HT2A receptors respectively) indicate that the new butyrophenones 8-[3-(4-fluorobenzoyl)propyl]-1-methyl-1,3,8-triazaspiro[4,5]de can-4-one (FMSP) and 8-[3-(4-iodobenzoyl)propyl]-1-methyl-1,3,8-triazaspiro[4,5]deca n-4-one (IMSP) exhibit a significantly higher selectivity for the 5-HT2A over D1, D2 and alpha1 receptors. Consequently, the radiolabelled analogues F[11C]MSP and 123I-MSP were prepared in attempt to obtain potential radiopharmaceuticals for in vivo imaging of neuronal 5-HT2A receptors with positron emission tomography (PET) and single photon emission tomography (SPET). F[11C]MSP was synthesized by reaction of [11C]CH3I with 8-[3-(4-fluorobenzoyl)propyl]-1,3,8-triazaspiro[4,5]decan-4- one (DMSP) in 12 +/- 3% radiochemical yield, whereas 123I-MSP was obtained in 82 +/- 8% radiochemical yield by a no-carrier-added Cu(I)-assisted [123I]iododebromination of 8-[3-(4-bromo-benzoyl)propyl]-1-methyl-1,3,8-triazaspiro[4,5]de can-4-ene (BrMSP). In vivo pharmacokinetic and brain binding characterization of 123I-MSP assessed in mice following intravenous injection, showed a fast clearance of 123I-MSP from blood and relatively high initial uptakes in the liver, kidneys and in the lung. Significant uptake and long retention were observed in the brain (up to 1.64% i.d., 60 min p.i.), with a regional accumulation of radioactivity consistent with the reported 5-HT2A receptors distribution in the brain. Frontal cortex to cerebellum ratio of 3.5 was calculated at 60 min p.i. Furthermore, the initial brain uptake was significantly reduced after pretreatment of the animals with ritanserin, a selective 5-HT2 antagonist, and by preinjection of the non-radiolabelled analog IMSP, thus indicating the specificity of the brain uptake. These data suggest that 123I-MSP may be a promising compound for studying the serotoninergic 5-HT2 receptors with SPET. Due to the low specific activity of F[11C]MSP currently obtained by the [11C]methylation reaction, systematic in vivo investigation of F[11C]MSP are as yet not feasable.
Animals↗