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F(18) -2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) has become a well established tool in staging and assessing therapy response in lymphoma. Incidental thyroid uptake on PET is not uncommon and can pose a diagnostic and management challenge. We retrospectively evaluate the prevalence and clinical significance of incidental FDG uptake in the thyroid gland in patients with lymphoma. 1868 lymphoma patients underwent PET and PET-CT between August 2002 and August 2008. 52 patients (2.8%) demonstrated FDG thyroid uptake (M  =  17, F =  35; mean age 63 yr). Thyroid uptake was determined as focal or diffuse, maximum standardized uptake values (SUVmax) recorded as well as SUV max ratio compared to background mediastinum activity (SUVR). Corresponding CT findings on PET-CT were evaluated independently. Results were correlated with clinical, histopathological and imaging follow-up. 30 (1.6%) patients had focal thyroid uptake. 16 (53%) had histological confirmation either by surgery (n  =  7) or FNA under USS (n  =  9). The final diagnosis was benign in 12/30 patients and malignant in 9/30. The malignancy risk for focal thyroid uptake was 30%. Five patients had intercurrent thyroid cancer (four papillary, one microinvasive follicular) and four had lymphomatous involvement. There was no significant difference between the mean sizes of benign (23.7 mm, range 12-34) and malignant nodules (23.6 mm, range 8-48). The mean SUVmax of malignant and benign nodules was 4.4 (range 1.8-10.1) and 3.2 (range 1.8-6.9) respectively with no statistically significant difference. 22 (1.2%) patients had diffuse FDG uptake in thyroid and benign aetiology was found in all with adequate follow-up (15/22). Focal FDG thyroid uptake on PET or PET-CT in lymphoma patients warrants further investigations. The malignancy risk is 30% either due to intercurrent thyroid cancer or lymphomatous involvement. SUVmax, SUVR and CT attenuation characteristics are not helpful in distinguishing between benign and malignant aetiologies. Diffuse thyroid uptake has a benign aetiology. [ABSTRACT FROM AUTHOR]

The use of 18F-FDG PET/CT for radiotherapy planning may lead to better tumor volume definition. Reproduction of the patient's position when setting up an 18F-FDG PET/CT scan for radio-therapy planning is more accurate if a radiation therapist is in-volved. The aim of this study was to compare setup time and staff radiation dose between radiation therapists and nuclear medicine technologists. Methods: Forty patients with newly di-agnosed head and neck or non-small cell lung cancer were prospectively recruited into this study. Twenty patients (10 with head and neck cancer and 10 with non-small cell lung cancer) underwent 18F-FDG PET/CT for radiotherapy planning, and 20 patients (10 with head and neck cancer and 10 with non-small cell lung cancer) underwent 18F-FDG PET/CT for staging. Setup time was measured, and a radiation monitor recorded the high-est dose (&mgr;Sv/h) to staff during setup. Results: For radiation therapists, the mean setup time for a lung scan (in min:s) was 5:22 ± 2:11 (range, 2:22-9:23), with a highest dose of 4.94 ± 3.78 JJLSV (range, 2.02-15.23 &mgr;Sv), and the mean setup time for a head and neck scan was 4:49 ± 1:45 (range, 2:03-8:21), with a highest dose of 3.93 ± 1.45 (iSv (range, 1.19-6.83 JJLSV). For nuclear medicine technologists, the mean setup time for a lung scan was 1:58 ± 0:24 (range, 1:17-2:38), with a highest dose of 3.30 ± 1.28 p.Sv (range, 1.92-5.47 (JLSV), and the mean setup time for a head and neck scan was 2:12 ± 0:38 (range, 1:03-3:16), with a highest dose of 3.10 ± 1.78 |a.Sv (range, 1.56-7.49 &mgr;Sv). Conclusion: This study showed that setup time and operator radiation dose were greater for radiation therapists setting up planning 18F-FDG PET/CT scans than for nuclear medicine technologists setting up routine 18F-FDG PET/CT scans. These results have implications for scheduling of radio-therapy planning PET/CT; however, the additional radiation dose was not considered to be significant. [ABSTRACT FROM AUTHOR]

Unlabelled: The use of (18)F-FDG PET/CT for radiotherapy planning may lead to better tumor volume definition. Reproduction of the patient's position when setting up an (18)F-FDG PET/CT scan for radiotherapy planning is more accurate if a radiation therapist is involved. The aim of this study was to compare setup time and staff radiation dose between radiation therapists and nuclear medicine technologists. Methods: Forty patients with newly diagnosed head and neck or non-small cell lung cancer were prospectively recruited into this study. Twenty patients (10 with head and neck cancer and 10 with non-small cell lung cancer) underwent (18)F-FDG PET/CT for radiotherapy planning, and 20 patients (10 with head and neck cancer and 10 with non-small cell lung cancer) underwent (18)F-FDG PET/CT for staging. Setup time was measured, and a radiation monitor recorded the highest dose (μSv/h) to staff during setup. Results: For radiation therapists, the mean setup time for a lung scan (in min:s) was 5:22 ± 2:11 (range, 2:22-9:23), with a highest dose of 4.94 ± 3.78 μSv (range, 2.02-15.23 μSv), and the mean setup time for a head and neck scan was 4:49 ± 1:45 (range, 2:03-8:21), with a highest dose of 3.93 ± 1.45 μSv (range, 1.19-6.83 μSv). For nuclear medicine technologists, the mean setup time for a lung scan was 1:58 ± 0:24 (range, 1:17-2:38), with a highest dose of 3.30 ± 1.28 μSv (range, 1.92-5.47 μSv), and the mean setup time for a head and neck scan was 2:12 ± 0:38 (range, 1:03-3:16), with a highest dose of 3.10 ± 1.78 μSv (range, 1.56-7.49 μSv). Conclusion: This study showed that setup time and operator radiation dose were greater for radiation therapists setting up planning (18)F-FDG PET/CT scans than for nuclear medicine technologists setting up routine (18)F-FDG PET/CT scans. These results have implications for scheduling of radiotherapy planning PET/CT; however, the additional radiation dose was not considered to be significant. [ABSTRACT FROM AUTHOR]

Abstract: A 6-month-old boy presented with a left parietal soft tissue swelling and CT findings of multiple calvarial lytic lesions. 18 F-FDG PET/CT demonstrated hypermetabolic lesions in the left parietal, right occipital, and right femoral bones. The left parietal lesion was excised, and pathology was consistent with Langerhans cell histiocytosis. Interim PET assessment following induction chemotherapy demonstrated a "mixed metabolic response" with discordant rise in metabolic activity of the right femoral lesion. Subsequent core biopsy of the femoral lesion revealed a non-Langerhans cell histiocytosis, likely juvenile xanthogranuloma. Here we describe a rare pediatric case of mixed histiocytosis, unveiled by serial 18 F-FDG PET/CT., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: 4-(N-(S-glutathionylacetyl)amino) phenylarsonous acid (GSAO) when conjugated with a bifunctional chelator 2,2'-(7-(1-carboxy-4-((2,5-dioxopyrrolidin-1-yl)oxy)-4- oxobutyl)-1,4,7-triazonane-1,4-diyl)diacetic acid (NODAGA) (hereafter referred to as Cell Death Indicator [CDI]), enters dead and dying cells and binds to 90kDa heat shock proteins (hsp90)., Objective: This study assesses stability, biodistribution, imaging, and radiation dosimetry of [68Ga]- Ga-CDI for positron emission tomography (PET)., Methods: Preparation of [ 68 Ga]Ga-CDI was performed as previously described. Product stability and stability in plasma were assessed using high-performance liquid chromatography. Biodistribution and imaging were conducted in ten healthy male Lewis rats at 1 and 2 h following intravenous [ 68 Ga]Ga-CDI injection. Human radiation dosimetry was estimated by extrapolation for a standard reference man and calculated with OLINDA/EXM 1.1., Results: Radiochemical purity of [ 68 Ga]Ga-CDI averaged 93.8% in the product and 86.7% in plasma at 4 h post-synthesis. The highest concentration of [ 68 Ga]Ga-CDI is observed in the kidneys; [ 68 Ga]Ga-CDI is excreted in the urine, and mean retained activity was 32.4% and 21.4% at 1 and 2 h post-injection. Lower concentrations of [ 68 Ga]Ga-CDI were present in the small bowel and liver. PET CT was concordant and additionally demonstrated focal growth plate uptake. The effective dose for [ 68 Ga]Ga-CDI is 2.16E-02 mSv/MBq, and the urinary bladder wall received the highest dose (1.65E-02 mSv/Mbq)., Conclusion: [ 68 Ga] Ga-CDI is stable and has favourable biodistribution, imaging, and radiation dosimetry for imaging of dead and dying cells. Human studies are underway., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Selective internal radiation therapy (SIRT) with radiolabeled Yttrium-90 (90Y) microspheres is a relatively new therapeutic option for patients with primary or secondary hepatic malignancy. However, the evaluation of the therapeutic efficacy on anatomic imaging alone is suboptimal. Functional imaging with F18-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is increasingly utilised in therapy monitoring in malignancy and provides an accurate assessment of metabolic response. We report a case of a 75-year-old gentleman with colorectal hepatic metastases who demonstrated a dramatic metabolic response on PET scan following SIRT. This case illustrates the utility of FDG PET in the assessment of the therapeutic efficacy of 90Y microspheres in colorectal hepatic metastases.