Gone with the Wind: JWST-MIRI Unveils a Strong Outflow from the Quiescent Stellar-mass Black Hole A0620-00

We present new observations of the black hole X-ray binary A0620-00 using the Mid-Infrared (MIR) Instrument on the James Webb Space Telescope, during a state where the X-ray luminosity is 9 orders of magnitude below Eddington, and coordinated with radio, near-infrared, and optical observations. The goal is to understand the nature of the excess MIR emission originally detected by Spitzer redward of 8 μm. The stellar-subtracted MIR spectrum is well modeled by a power law with a spectral index of α = 0.72 ± 0.01, where the flux density scales with frequency as Fν ∝ να. The spectral characteristics, along with rapid variability—a 40% flux flare at 15 μm and 25% achromatic variability in the 5–12 μm range—rule out a circumbinary disk as the source of the MIR excess. The Low Resolution Spectrometer reveals a prominent emission feature at 7.5 μm, resulting from the blend of three hydrogen recombination lines. While the contribution from partially self-absorbed synchrotron radiation cannot be ruled out, we argue that thermal bremsstrahlung from a warm (a few tens of thousands of Kelvin) wind accounts for the MIR excess; the same outflow is responsible for the emission lines. The inferred mass outflow rate indicates that the system’s low luminosity is due to a substantial fraction of the mass supplied by the donor star being expelled through a wind rather than accreted onto the black hole

Magnetic resonance imaging, computed tomography, and 68Ga-DOTATOC positron emission tomography for imaging skull base meningiomas with infracranial extension treated with stereotactic radiotherapy - a case series

<p>Abstract</p> <p>Introduction</p> <p>Magnetic resonance imaging (MRI) and computed tomography (CT) with ⁶⁸Ga-DOTATOC positron emission tomography (⁶⁸Ga-DOTATOC-PET) were compared retrospectively for their ability to delineate infracranial extension of skull base (SB) meningiomas treated with fractionated stereotactic radiotherapy.</p> <p>Methods</p> <p>Fifty patients with 56 meningiomas of the SB underwent MRI, CT, and ⁶⁸Ga-DOTATOC PET/CT prior to fractionated stereotactic radiotherapy. The study group consisted of 16 patients who had infracranial meningioma extension, visible on MRI ± CT (MRI/CT) <it>or </it>PET, and were evaluated further. The respective findings were reviewed independently, analyzed with respect to correlations, and compared with each other.</p> <p>Results</p> <p>Within the study group, SB transgression was associated with bony changes visible by CT in 14 patients (81%). Tumorous changes of the foramen ovale and rotundum were evident in 13 and 8 cases, respectively, which were accompanied by skeletal muscular invasion in 8 lesions. We analysed six designated anatomical sites of the SB in each of the 16 patients. Of the 96 sites, 42 had infiltration that was delineable by MRI/CT and PET in 35 cases and by PET only in 7 cases. The mean infracranial volume that was delineable in PET was 10.1 ± 10.6 cm³, which was somewhat larger than the volume detectable in MRI/CT (8.4 ± 7.9 cm³).</p> <p>Conclusions</p> <p>⁶⁸Ga-DOTATOC-PET allows detection and assessment of the extent of infracranial meningioma invasion. This method seems to be useful for planning fractionated stereotactic radiation when used in addition to conventional imaging modalities that are often inconclusive in the SB region.</p

Implicatzions of nuclear medicine imaging using radioactively labelled amino acids in the neurooncology and in the diagnosis of head and neck cancer

Titel und Inhaltsverzeichnis 1. Einleitung 7 1.1 1.2 1.3 1.4 Nuklearmedizinische Bildgebung in der onkologischen Diagnostik Bildgebende Diagnostik von Hirntumoren Magnetresonanztomographie Bildgebende Diagnostik in der Nachsorge von Kopf/Hals-Tumoren 8 11 12 19 21 2. Darstellung der eigenen Arbeiten 25 2.1 2.2 Diagnostik von Hirntumoren: 123I-IMT SPECT und 18F-FET PET Diagnostik von Kopf/Halstumoren: 123I-IMT SPECT/Low-dose-CT 26 30 3. Relevante Originalarbeiten 32 4. Zusammenfassung 34 5. Literaturverzeichnis 36SPECT oder PET mit radioaktiv markierten Aminosäuren eignen sich zur Erfassung des Stoffwechsels von Hirntumoren und erlauben eine Früherkennung von Rezidiven sowie eine präzisere Erfassung von Tumorgrenzen. Somit liefern sie eine relevante Zusatzinformation zur MRT. Auf der anderen Seite, ist eine Bildfusion mit MRT für die korrekte Beurteilung der nuklearmedizinischen Aufnahmen unabdingbar. Die Vorteile der radioaktiv markierten Aminosäuren in der neuroonkologischen Diagnostik liegen zu einem in deren Fähigkeit, in nahezu allen hoch- und niedrigmalignen Hirntumoren zu akkumulieren, zum anderen in der Tatsache, dass der Aminosäurenverbrauch im umgebenden gesunden Hirngewebe sehr niedrig ist und die Tumoren dadurch besser dargestellt werden können. Die 123I-IMT SPECT besitzt eine höhere Sensitivität und Spezifität beim Nachweis von Gliomrezidiven als ein alternatives Verfahren 1H-MR- Spektroskopie. Die PET mit dem kürzlich eingeführten Tracer 18F-FET bietet eine bessere räumliche Auflösung und erscheint für die zukünftige klinische Anwendungen vielversprechend. Die 18F-FET-PET ist geeigneter als die 18F-FDG PET für die Biopsieplanung von nicht Gd-aufnehmenden Hirntumoren und hilfreich für die Beurteilung der Tumorausdehnung bei Glioblastomrezidiven. In der Diagnostik von vorbehandelten Kopf/Hals-Tumoren sind radioaktiv markierte Aminosäuren bei fraglichen Befunden der morphologischen Bildgebung von Nutzen, um Rezidive von den therapiebedingten Veränderungen zu differenzieren. Die Aussagekraft der 123I-IMT SPECT kann erhöht werden, wenn zur Akquisition eine CT-fähige Gammakamera verwendet wird. Für die Diagnose eines Rezidivtumors besitzt die kombinierte 123I-IMT SPECT/Low-dose-CT-Bildgebung einen hohen positiven Vorhersagewert.An advantage of the radioactively labelled amino acids in the neurooncological diagnostics lies in their ability to accumulate in nearly all brain tumours. Moreover, the amino acid consumption in the surrounding healthy brain tissue is very low, and the tumours can be therefore easily delineated. The nuclear medicine methods (PET, SPECT) posess distinctly better ability to discriminate viable tumour from tissue alterations such as peritumoural edema, postoperative scar and radiation necrosis, as compared with the standard imaging tools (CT, MRI). This allows a more precise assessment of tumour extension and diagnosis of residual and recurrent brain tumours. In our study, SPECT using an amino acid 123I-IMT was superior to an alternative procedure, 1H-MRS at distinguishing recurrent/residual glioma from post-therapeutic changes. On the other side, the fusion with MRI is mandatory for the correct judgement of the SPECT images. PET with the recently introduced amino tracer 18F-FET offers a better spatial resolution and seems to be promising for the future clinical applications. 18F-FET PET is more suitable than 18F-FDG PET for the biopsy planning of not Gd-enhancing brain tumours and is helpful for for therapy planning in patients with recurrent glioblastomas. 123I-IMT-SPECT using integrated low dose CT appears to be a helpful complementary imaging tool for the detection of local recurrences and lymph node metastases of head and neck cancer. The advantage of the method is a high positive predictive value for the diagnosis of relapsed tumour

MON-196 A Single-Center Experience of Patients with Metastatic Pheochromocytoma/Paraganglioma Treated with 177Lu-DOTATATE

Abstract The prevalence of metastatic pheochromocytoma/paraganglioma (PPGL) is reported to be 3% to 36% of all the cases. The five-year overall survival rate of such patients ranges from 40 to 77%. The management of metastatic PPGL is challenging taking into account the fact that the optimal strategies for clinical care beyond surgical resection are not guided yet. Peptide receptor radionuclide therapy (PRRT) using somatostatin analogues is effective in other neuroendocrine tumours, can be indicated in patients with positive scans for the respective radiopharmaceuticals. We report preliminary data of the prospective study aimed to assess the safety and efficacy outcomes of 177Lu-DOTATATE for 6 patients with histologically confirmed PPGLs with metastatic progression after the complete PPGL surgery. The mean age of our cohort was 53 years (range 14–73); an equal number of male and female patients was included. Two of them had germline mutations in RET and SDHB genes, respectively. Radiological response utilized RECIST 1.1 criteria; toxicity was graded according to common terminology criteria for adverse events version 4. PPRT scheme varied between three and four cycles. Partial response (PR) was achieved in one and stable disease (SD) in four 4 patients. One patient had treatment refractory with disease progression and dramatic increase of chromogranin A concentration (+268%). Biochemical response (&amp;gt;50% decrease) of chromogranin A was found in 1/6 patients and of catecholamines in 2/6 patients. No hematological or kidney toxicity grade 3–4 was registered. Median overall survival and median progression-free survival rate will be reported after the end of the study. To date, about 250 PPGL patients have been treated with PRRT. PRRT using 177Lu-DOTA-SSAs has shown promise for treatment of PPGLs with improvement of clinical symptoms and/or disease control in the setting of retrospective small case reports or case series. However, more well-designed prospective studies are required to confirm these findings.</jats:p