Asia Oceania Journal of Nuclear Medicine and Biology最新文献

Although ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is an established method for the staging of malignancies, benign lesions (e.g, active inflammatory lesions) often show increased metabolic activity. Herpes zoster is the clinical manifestation of the activation and replication of dormant varicella-zoster virus (VZV) in individuals with decreased cell-mediated immunity. Although the diagnosis of herpes zoster is clinical, it is sometimes observed incidentally during imaging for another disease. We describe the case of a 67-year-old Japanese female patient diagnosed with cervical cancer in whom FDG-PET/CT revealed herpes zoster manifestations: hypermetabolic cutaneous lesions in the buttock and pelvic lymph node involvement. The resected lymph nodes showed no malignant lesions but revealed lymphoid follicle formation, probably related to viral infection. There has been no report comparing FDG-PET findings of lymph nodes with histologic findings; the present findings are compatible with a clinically VZV-induced inflammatory reaction in regional lymph nodes, which increased FDG accumulation. Active infection with VZV displays increased FDG uptake in regional lymph nodes and may lead to incorrect malignant disease management in oncology. Misdiagnoses can be avoided by a careful interpretation by experienced nuclear medicine physicians as well as proper clinical evaluation.

Objectives: Miltuximab^® is a chimeric antibody targeting Glypican-1 (GPC-1), a cell surface antigen which is overexpressed in solid cancers. Miltuximab^® has shown promising safety and efficacy in radioimmunotherapy models of prostate cancer. This first in human study used Miltuximab^® radiolabelled with Gallium-67 ([⁶⁷Ga]Ga-DOTA-Miltuximab^®). The primary study endpoint was to establish safety and tolerability of Miltuximab^®. Secondary endpoints were biodistribution, tumour targeting and pharmacokinetic analysis.

Methods: Four cohorts of three patients (9 with advanced prostate cancer, 2 with pancreatic and 1 with bladder cancer) were dosed with 1 mg, ~250 MBq of [⁶⁷Ga]Ga-DOTA-Miltuximab^®. Cohort 1 received [⁶⁷Ga]Ga-DOTA-Miltuximab^® alone, while cohorts 2-4 were pre-infused with increasing doses (3.5, 11.5 and 24 mg, respectively) of unlabelled Miltuximab^®-DOTA 1 hour prior to [⁶⁷Ga]Ga-DOTA-Miltuximab^®. Safety and tolerability were assessed by clinical and standard laboratory assessments. Patients underwent whole body gamma-camera scans and SPECT/CT scans up to 144 h post-infusion. Total organ radiation exposure was determined by dosimetry of whole-body gamma scans.

Results: The dosing regimen was well tolerated, with no drug-related adverse events observed. Liver and spleen uptake of [⁶⁷Ga]Ga-DOTA-Miltuximab^® was observed. Liver uptake was reduced by pre-infusion of unlabelled Miltuximab^®-DOTA. Dosimetry analysis showed a favorable exposure profile. [⁶⁷Ga]Ga-DOTA-Miltuximab^® targeting to tumour sites was observed in two prostate cancer patients who had failed enzalutamide treatment. Higher doses of unlabelled antibody achieved lower liver uptake and increased antibody serum half life.

Conclusions: This study is the first in human for Miltuximab^® a first in class antibody targeting GPC-1. The trial met its primary endpoint of safety, demonstrating its potential as a safe and tolerable monoclonal antibody. This safety data, together with targeting to tumour lesions and biodistribution information supports the further clinical development of Miltuximab^® as a theranostic agent in a planned Phase I human trial.

A limitation to the wider introduction of personalised dosimetry in theranostics is the relative paucity of imaging radionuclides with suitable physical and chemical properties to be paired with a long-lived therapeutic partner. As most of the beta-emitting therapeutic radionuclides emit gamma radiation as well they could potentially be used as the imaging radionuclide as well as the therapeutic radionuclide. However, the downsides are that the beta radiation will deliver a significant radiation dose as part of the treatment planning procedure, and the gamma radiation branching ratio is often quite low. Gallium-67 has been in use in nuclear medicine for over 50 years. However, the tremendous interest in gallium imaging in theranostics in recent times has focused on the PET radionuclide gallium-68. In this article it is suggested that the longer-lived gallium-67, which has desirable characteristics for imaging with the gamma camera and a suitably long half-life to match biological timescales for drug uptake and turnover, has been overlooked, in particular, for treatment planning with radionuclide therapy. Gallium-67 could also allow non-PET facilities to participate in theranostic imaging prior to treatment or for monitoring response after therapy. Gallium-67 could play a niche role in the future development of personalised medicine with theranostics.

Brain metabolic imaging using ¹⁸F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) with contemporaneous low-dose CT may be used to assess neurodegenerative diseases. In contrast to oncology whole-body FDG PET, qualitative assessment alone in brain FDG PET is subjective and vulnerable to visual interference due to high physiologic background activity. Therefore, mild changes in brain metabolism may be visually undetectable by qualitative interpretation alone, resulting in diagnostic inaccuracy. To overcome this, some institutions may employ an objective comparison to a normal reference database. To date, there is limited literature describing brain metabolic changes in rare genetic neurodegenerative diseases such as Niemann-Pick disease Type C, spinocerebellar ataxia and Huntington disease. In this case series, we illustrate the typical FDG PET findings in the cortex and deep grey matter for these rare diseases, utilising normal database comparison including three dimensional Stereotactic Surface Projection (3D-SSP) mapping. These comparisons can generate 3D-SSP maps where metabolic changes may be expressed in standard deviations from normal (z-score) and visually depicted in a scale of colours to improve diagnostic accuracy.

A 65-year-old man presented with intermittent abdominal pain for three months. Abdominal ultrasonography revealed a mass in the body of the pancreas. Moreover, abdominal contrast-enhancing computed tomography revealed a homogenously enhancing mass in the body of the pancreas. Scan findings were in favor of the neuroendocrine tumor, and the serum chromogranin level was slightly raised (111.9 ng/ml, normal <98). He had no history of vomiting, jaundice, melena, hematemesis, constipation, diarrhea, weight gain, weight loss, loss of appetite, and fever. He also had no symptoms related to the excessive production of catecholamines, such as hypertension. The patient was referred for Ga-68 DOTANOC positron emission tomography-computed tomography (Ga-68 DOTANOC PET-CT) for further evaluation. The scan was done to rule out metastatic disease or other synchronous lesions to plan surgical excision. The Ga-68 DOTANOC PET-CT revealed a pancreatic lesion with no other abdominal lesions. We noted multiple tracer avid soft tissue lesions on both sides of the neck that were not diagnosed previously. This case report demonstrates a rare case with multiple paragangliomas diagnosed by the Ga-68 DOTANOC PET-CT. This finding could lead to changes in patient management.

Objectives: Only few studies have assessed the use of gallium citrate-67 single-photon emission computed tomography/computed tomography (⁶⁷Ga-SPECT/CT) for localizing the foci of classic fever of unknown origin (FUO) and inflammation of unknown origin (IUO). Hence, the current study aimed to assess the diagnostic contribution of ⁶⁷Ga-SPECT/CT in a tertiary referral setting where nuclear imaging tests are performed after an unsuccessful comprehensive primary diagnostic workup.

Methods: We retrospectively assessed the medical records of 27 adult patients with FUO/IUO who had an unsuccessful diagnostic workup and who underwent ⁶⁷Ga-SPECT/CT for the localization of FUO/IUO foci in our university hospital between 2013 and 2019. The primary outcome was diagnostic yield. The secondary outcomes were overall clinical efficacy and spontaneous remission of FUO/IUO symptoms in patients with a negative ⁶⁷Ga-SPECT/CT finding.

Results: Almost all patients completed the recommended diagnostic workup, except for urine culture and abdominal ultrasonography. Moreover, prior to ⁶⁷Ga-SPECT/CT, all patients underwent thoraco-abdominopelvic CT scan, which was a non-diagnostic procedure. After a median follow-up of 843 days, the cause was identified in 16 (59%) patients. ⁶⁷Ga-SPECT/CT successfully localized the FUO/IUO foci in eight patients (diagnostic yield = 30%; 95% confidence interval [CI]: 14%-50%). However, the causes remained unknown during follow-up in 11 (41%) patients. Among them, five experienced spontaneous regression of symptoms. ⁶⁷Ga-SPECT/CT was negative in four of the five patients with spontaneous regression in symptoms without a definite cause. Considering this an important event, the overall clinical efficacy of ⁶⁷Ga-SPECT/CT increased to 44% (95% CI: 25%-65%).

Conclusion: ⁶⁷Ga-SPECT/CT had an acceptable diagnostic yield for the localization of FUO/IUO foci, which are challenging to diagnose, in a contemporary tertiary referral care setting. In patients who experienced spontaneous regression in symptoms with an unexplained cause, the absence of abnormal uptake might indicate prospective spontaneous remission. Thus, ⁶⁷Ga-SPECT/CT could be an active first-line nuclear imaging modality in settings where fluorine-18-fluorodeoxy glucose positron emission tomography and computed tomography is not available for the assessment of FUO/IUO causes.

Objectives: ¹⁸F-Fluorodeoxyglucose (FDG) uptake in children is different from that in adults. Physiological accumulation is known to occur in growth plates, but the pattern of distribution has not been fully investigated. Our aim was to evaluate the metabolic activity of growth plates according to age and location.

Methods: We retrospectively evaluated 89 PET/CT scans in 63 pediatric patients (male : female=25 : 38, range, 0-18 years). Patients were classified into four age groups (Group A: 0-2 years, Group B: 3-9 years, Group C: 10-14 years and Group D: 15-18 years). The maximum standardized uptake value (SUV_max) of the proximal and distal growth plates of the humerus, the forearm bones and the femur were measured. The SUV_max of each site and each age group were compared and statistically analyzed. We also examined the correlations between age and SUV_max.

Results: As for the comparison of SUV_max in each location, the SUV_max was significantly higher in the distal femur than those in the other sites (p< 0.01). SUV_max in the distal humerus and the proximal forearm bones were significantly lower than those in the other sites (p< 0.01). In the distal femur, there was large variation in SUV_max, while in the distal humerus and the proximal forearm bones, there was small variation. As for the comparison of SUV_max in each age group, the SUV_max in group D tended to be lower than those in the other groups, but in the distal femur, there was no significant difference among each age group.

Conclusion: Our data indicate that FDG uptake in growth plates varies depending on the site and age with remarkable uptake especially in the distal femur.

Prostate cancer is considered to be the most common solid cancer affecting men worldwide and leading to a significant morbidity and mortality. Metastases are usually seen in bone or lymph nodes. For recurrent disease, PET imaging with ⁶⁸Ga-PSMA-11 (also known as HBED-CC, Glu-urea-Lys(Ahx)-HBED-CC, and PSMA-HBED-CC) is widely used. However, preparation of ⁶⁸Ga-PSMA ligand requires the presence of radiochemistry facilities and can therefore not be utilized in centers lacking such facilities. Recently, copper labeled prostate-specific membrane antigen positron emission tomography (⁶⁴Cu-PSMA PET/CT) demonstrated promising results in patients with recurrent disease and in the primary staging of selected patients with progressive local disease. In the present case, a rare manifestation site of a metastatic lesion in a patient with advanced prostate cancer is detected by ⁶⁴Cu-PSMA PET/CT.

High-grade B-cell lymphoma, an aggressive form of Non-Hodgkin's Lymphoma, is known as a double or triple hit lymphoma based on the presence of MYC and BCL2 without or with BCL6 genetic rearrangements, respectively. It carries a poorer prognosis, compared to other variants of B-cell lymphoma, and its management also differs which requires more intensive chemotherapy in contrast to the routine regimen. Terminal deoxynucleotidyl transferase (TdT), a marker of immaturity is commonly expressed in B-cell lymphoblastic leukemia or lymphoma (B cell ALL) which is absent in mature forms of B-cell lymphoma. The TdT is expressed in high-grade B-cell lymphoma; therefore, it poses a classification and management dilemma, which should be accurately differentiated from B-cell ALL and mandates molecular analysis. Herein, we report a case of a 52-year-old female with biopsy reported as high-grade B-cell lymphoma with TdT expression. She was referred for Fluor-deoxyglucose (FDG) Positron Emission Tomography-Computed Tomography (PET/CT) scan for staging in the absence of molecular analysis for B-cell ALL. It was diagnosed as lymphoma on FDG PET/CT based on its characteristic findings of extensive extranodal involvement of multiple organs with no significant lymphadenopathy establishing the incremental value of FDG PET/CT scan, which helped the clinician to arrive at a conclusion.

Epilepsy is a disorder of the brain, which is characterized by recurrent epileptic seizures. These patients are generally treated with antiepileptic drugs. However, more than 30% of the patients become medically intractable and undergo a series of investigations to define candidates for epilepsy surgery. Nuclear Medicine studies using Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) radiopharmaceuticals are among the investigations used for this purpose. Since available guidelines for the investigation of surgical candidates are not up-to-date, The Nuclear Medicine Society of Thailand, The Neurological Society of Thailand, The Royal College of Neurological Surgeons of Thailand, and The Thai Medical Physicist Society has collaborated to develop this Thai national guideline for Nuclear Medicine study in epilepsy. The guideline focuses on the use of brain perfusion SPECT and F-18 fluorodeoxyglucose PET (FDG-PET), the mainly used methods in day-to-day practice. This guideline aims for effective use of Nuclear Medicine investigations by referring physicians e.g. epileptologists and neurologists, radiologists, nuclear medicine physicians, medical physicists, nuclear medicine technologists and technicians.