What to Trust, PSA or [Ga-68]Ga-PSMA-11:Learn from Experience

Brain metastases from prostate cancer typically occur in the more advanced stages of the disease. Clinically, the early diagnosis of visceral disease is crucial, impacting on patient's management and prognosis. Although magnetic resonance imaging (MRI) is the modality of choice for the detection of brain metastases, it is not routinely performed in the surveillance of prostate cancer patients unless neurological manifestations appear. Prostate-specific membrane antigen (PSMA) is a glycoprotein, a membrane-bound metallopeptidase, overexpressed in more than 90% of prostate cancer cells. This molecular target is a suitable tissue biomarker for prostate cancer functional imaging. We present a case of a 73-year gentleman diagnosed with prostate adenocarcinoma and surgically treated (pT3bN1Mx, Gleason Score of 9) in February 2016. Subsequently, he underwent androgen deprivation therapy because of the occurrence of a bone metastasis. Between 2016 and January 2019 PSA levels were maintained under control. Starting from September 2019, it progressively raised up to 0.85 ng/mL with a doubling time of 3.3 months. Therefore, he performed a [Ga-68]Ga-PSMA-11 PET/CT which showed a focal radiopharmaceutical uptake in the right temporal lobe corresponding to the presence of a rounded cystic lesion on brain MRI. The subsequent excisional biopsy diagnosed a prostate adenocarcinoma metastasis. PSMA expression has been reported in brain parenchyma after ischemic strokes and in some brain tumors including gliomas, meningiomas, and neurofibromas. In our case, the lack of symptoms and the relatively low PSA level raised questions about the nature of the lesion, posing the differential diagnosis between brain metastases and primary brain tumor. Finally, our case shows the capability of [Ga-68]Ga-PSMA-11 PET/CT to detect metachronous distant brain metastases in a low biochemical recurrent asymptomatic prostate cancer patient, indicating that proper acquisition - from the vertex to thigh - should be always considered, regardless of the PSA level

YTTRIUM-90 RADIOEMBOLIZATION AS A PROMISING THERAPEUTIC OPTION IN PATIENTS WITH LIVER METASTASES FROM MEDULLARY THYROID CARCINOMA

Surgical resection is the gold standard in the case of single large metastases fro medullary thyroid carcinoma (MTC) but they are often multiple and disseminated throughout the parenchyma. In this situation, chemoembolization should be considered in patients with disseminated tumor less than 30mm in size involving less than a third of the liver. Otherwise, systemic therapy with tyrosine kinase inhibitors (TKI) is the only remaining therapeutic solution, but it is indicated only in patients with significant tumor burden and documented disease progression. Patients with initial presentation of liver metastases from MTC who do not meet the indication criteria for surgery or chemoembolization remain untreated until disease progression is not sufficient to justify the use of TKIs. In this setting, transarterial radioembolization (SIRT) is proposed as a promising therapeutic option. SIRT is suitable for the treatment of liver metastases from neuroendocrine tumor and since MTC belongs to this category, the indication for therapy is feasible. The proposal of radioembolization in these patients is to slow down the progression of the disease in order to postpone the use of TKIs. The primary aim of the present study is to evaluate the efficacy and safety of SIRT in patients with liver metastases from MTC. Other secondary purposes include the assessment of the trend of tumor-specific laboratory markers and the study of dosimetry and radiobiology issues related to SIRT

Negative DAT-SPECT in Old Onset Parkinson's Disease: An Additional Pitfall?

Background Scans without evidence of dopaminergic deficit (SWEDDs) refer to patients clinically diagnosed with Parkinson's disease (PD), but showing normal findings on dopamine transporter single-photon emission computed tomography (DAT-SPECT). This entity remains highly debated, but recent findings suggesting that DAT-SPECT does not reflect either nigral cell bodies or striatal fibers of dopaminergic nigrostriatal neurons could improve our understanding of SWEDDs. Notably, compensatory downregulation of DAT in the early stages of PD seems to be less efficient in older-onset than in young-onset patients. Cases We report eight patients with old-onset clinical parkinsonism and a positive response to levodopa in which DAT-SPECT was normal both visually and semiquantitatively. Two subjects demonstrated an abnormal scan when repeated later. Conclusions We suggest that old-onset patients may truly have dopaminergic degeneration despite normal imaging results, presumably because they are diagnosed in the early stages confirming less efficient striatal compensatory strategies in old-age onset PD

A new study of 25Mg (\u3b1, n) 28Si angular distributions at E\u3b1 = 3-5 MeV

The observation of 26Al gives us the proof of active nucleosynthesis in the Milky Way. However the identification of the main producers of 26Al is still a matter of debate. Many sites have been proposed, but our poor knowledge of the nuclear processes involved introduces high uncertainties. In particular, the limited accuracy on the 25Mg(\u3b1, n)28Si reaction cross section has been identified as the main source of nuclear uncertainty in the production of 26Al in C/Ne explosive burning in massive stars, which has been suggested to be the main source of 26Al in the Galaxy. We studied this reaction through neutron spectroscopy at the CN Van de Graaff accelerator of the Legnaro National Laboratories. Thanks to this technique we are able to discriminate the (\u3b1, n) events from possible contamination arising from parasitic reactions. In particular, we measured the neutron angular distributions at 5 different beam energies (between 3 and 5 MeV) in the 17.5\u25e6-106\u25e6 laboratory system angular range. The presented results disagree with the assumptions introduced in the analysis of a previous experiment

"Malattie dell’apparato respiratorio. Pneumologia e chirurgia toracica"

La tecnica tomografica permette di riconoscere con accuratezza la sede, le dimensioni, le porzioni anatomiche del polmone e le caratteristiche dei processi patologici. Esistono due tecniche di tomografia a emissione, quella a emissione di singolo fotone, la SPET, e quella a emissione di positroni, la PET (Tab. 7-11). Al fine di ottenere un'accurata diagnosi e una corretta interpretazione delle immagini scintigrafiche è diventato fondamentale disporre affianco alle immagini funzionali (SPET o PET) immagini di tipo morfologico (Rx, TC e RM). Inizialmente si è provveduto a effettuare fusioni di immagini provenienti da apparecchiature differenti e acquisite in tempi diversi mediante l'utilizzo di opportuni sistemi software. Attualmente si dispone però di sistemi hardware ibridi, ovvero un unico sistema con integrati SPET o PET e CT o più di recente SPET o PET e RM, in uno stesso gantry, con cui le immagini di due modalità vengono acquisite in un'unica sessione e co-registrate, senza che il paziente si muova dal lettino. Si ottengono così immagini multimodali, funzionali e morfologiche contemporaneamente. La utilizzazione di macchine SPECT/CT per ottenere contemporaneamente e durante un singolo esame sia le immagini di medicina nucleare (scintigrafie polmonari perfusive /ventilatorie) che la TC, rappresentano la migliore scelta tecnica per lo studio delle patologie polmonari. L'indagine che visualizza la distribuzione e la concentrazione del radiofarmaco nei due polmoni o nel torace viene definita scintigrafia statica. Le proiezioni possibili sono: anteriore, posteriore, laterali e oblique a 45° anteriore e posteriore. Se l'esame viene esteso all'intero corpo nelle due proiezioni, anteriore e posteriore, viene detto total body (IB) o whole body (WB). Le immagini WB sono utili nella stadiazione e ristadiazione di pazienti con patologie neoplastiche o infiammatorie con possibile disseminazione in varie sedi come anche nel ricercare patologie la cui sede di origine non è nota. Tale indagine WB rappresenta il primo step per guidare indagini su specifici distretti anatomici sede di patologie. Quando si acquisiscono immagini in sequenza sul torace è possibile ottenere la visualizzazione delle modificazioni spaziali della concentrazione del radiofarmaco nel tempo. Queste vengono definite scintigrafie dinamiche. Queste ultime sono caratterizzate dalla frequenza temporale, con cui vengono ottenute le immagini, e dal tempo di durata dell'esame (per esempio: 1 immagine ogni minuto per 60 minuti). Si può dire che nella maggioranza dei casi i radiofarmaci impiegati in pneumologia si distribuiscono nelle porzioni integre e normo-funzionanti del polmone, mentre nei processi patologici la loro concentrazione appare ridotta o assente. La lesione viene definita ipofissante, non fissante, fredda. Quando si utilizzano radiofarmaci con specifico tropismo per il tessuto patologico, la lesione accumula il radiofarmaco e si mette in evidenza come area Iperattiva o positiva. I radiofarmaci che permettono questo tipo di immagine sono detti indicatori positivi di lesione