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  1. Article ; Online: Localization of TSH-secreting pituitary adenoma using 11C-methionine image subtraction

    Daniel Gillett / Russell Senanayake / James MacFarlane / Merel van der Meulen / Olympia Koulouri / Andrew S. Powlson / Rosy Crawford / Bethany Gillett / Nick Bird / Sarah Heard / Angelos Kolias / Richard Mannion / Luigi Aloj / Iosif A. Mendichovszky / Heok Cheow / Waiel A. Bashari / Mark Gurnell

    EJNMMI Research, Vol 12, Iss 1, Pp 1-

    2022  Volume 10

    Abstract: Abstract Background Pituitary adenomas (PA) affect ~ 1:1200 of the population and can cause a wide range of symptoms due to hormone over-secretion, loss of normal pituitary gland function and/or compression of visual pathways, resulting in significantly ... ...

    Abstract Abstract Background Pituitary adenomas (PA) affect ~ 1:1200 of the population and can cause a wide range of symptoms due to hormone over-secretion, loss of normal pituitary gland function and/or compression of visual pathways, resulting in significantly impaired quality of life. Surgery is potentially curative if the location of the adenoma can be determined. However, standard structural (anatomical) imaging, in the form of MRI, is unable to locate all tumors, especially microadenomas (< 1 cm diameter). In such cases, functional imaging [11C-methionine PET/CT (Met-PET)] can facilitate tumor detection, although may be inconclusive when the adenoma is less metabolically active. We, therefore, explored whether subtraction imaging, comparing findings between two Met-PET scans with medical therapy-induced suppression of tumor activity in the intervening period, could increase confidence in adenoma localization. In addition, we assessed whether normalization to a reference region improved consistency of pituitary gland signal in healthy volunteers who underwent two Met-PET scans without medical suppression. Results We found that the mean percentage differences in maximum pituitary uptake between two Met-PET scans in healthy volunteers were 2.4% for (SUVr) [cerebellum], 8.8% for SUVr [pons], 5.2% for SUVr [gray matter] and 23.1% for the SUVbw [no region]. Laterality, as measured by contrast–noise ratio (CNR), indicated the correct location of the adenoma in all three image types with mean CNR values of 6.2, 8.1 and 11.1 for SUVbw, SUVbwSub and SUVrSub [cerebellum], respectively. Subtraction imaging improved CNR in 60% and 100% of patients when using images generated from SUVbw [no region] and SUVr [cerebellum] scans compared to standard clinical SUVbw imaging. Conclusions Met-PET scans should be normalized to the cerebellum to minimize the effects of physiological variation in pituitary gland uptake of 11C-methionine, especially when comparing serial imaging. Subtraction imaging following endocrine suppression of ...
    Keywords 11C-methionine PET ; Human pituitary tumors ; Normalization ; Subtraction imaging ; Medical physics. Medical radiology. Nuclear medicine ; R895-920
    Subject code 610
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher SpringerOpen
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Development of a bespoke phantom to optimize molecular PET imaging of pituitary tumors

    Daniel Gillett / Daniel Marsden / Rosy Crawford / Safia Ballout / James MacFarlane / Merel van der Meulen / Bethany Gillett / Nick Bird / Sarah Heard / Andrew S. Powlson / Thomas Santarius / Richard Mannion / Angelos Kolias / Ines Harper / Iosif A. Mendichovszky / Luigi Aloj / Heok Cheow / Waiel Bashari / Olympia Koulouri /
    Mark Gurnell

    EJNMMI Physics, Vol 10, Iss 1, Pp 1-

    2023  Volume 23

    Abstract: Abstract Background Image optimization is a key step in clinical nuclear medicine, and phantoms play an essential role in this process. However, most phantoms do not accurately reflect the complexity of human anatomy, and this presents a particular ... ...

    Abstract Abstract Background Image optimization is a key step in clinical nuclear medicine, and phantoms play an essential role in this process. However, most phantoms do not accurately reflect the complexity of human anatomy, and this presents a particular challenge when imaging endocrine glands to detect small (often subcentimeter) tumors. To address this, we developed a novel phantom for optimization of positron emission tomography (PET) imaging of the human pituitary gland. Using radioactive 3D printing, phantoms were created which mimicked the distribution of 11C-methionine in normal pituitary tissue and in a small tumor embedded in the gland (i.e., with no inactive boundary, thereby reproducing the in vivo situation). In addition, an anatomical phantom, replicating key surrounding structures [based on computed tomography (CT) images from an actual patient], was created using material extrusion 3D printing with specialized filaments that approximated the attenuation properties of bone and soft tissue. Results The phantom enabled us to replicate pituitary glands harboring tumors of varying sizes (2, 4 and 6 mm diameters) and differing radioactive concentrations (2 ×, 5 × and 8 × the normal gland). The anatomical phantom successfully approximated the attenuation properties of surrounding bone and soft tissue. Two iterative reconstruction algorithms [ordered subset expectation maximization (OSEM); Bayesian penalized likelihood (BPL)] with a range of reconstruction parameters (e.g., 3, 5, 7 and 9 OSEM iterations with 24 subsets; BPL regularization parameter (β) from 50 to 1000) were tested. Images were analyzed quantitatively and qualitatively by eight expert readers. Quantitatively, signal was the highest using BPL with β = 50; noise was the lowest using BPL with β = 1000; contrast was the highest using BPL with β = 100. The qualitative review found that accuracy and confidence were the highest when using BPL with β = 400. Conclusions The development of a bespoke phantom has allowed the identification of optimal ...
    Keywords 3D printing radioactive phantom ; Optimization of molecular PET imaging ; Pituitary tumors/adenomas ; Medical physics. Medical radiology. Nuclear medicine ; R895-920
    Subject code 616
    Language English
    Publishing date 2023-06-01T00:00:00Z
    Publisher SpringerOpen
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Inter-library loan at ZB MED

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  3. Article ; Online: Methods of 3D printing models of pituitary tumors

    Daniel Gillett / Waiel Bashari / Russell Senanayake / Daniel Marsden / Olympia Koulouri / James MacFarlane / Merel van der Meulen / Andrew S. Powlson / Iosif A. Mendichovszky / Heok Cheow / Nick Bird / Angelos Kolias / Richard Mannion / Mark Gurnell

    3D Printing in Medicine, Vol 7, Iss 1, Pp 1-

    2021  Volume 14

    Abstract: Abstract Background Pituitary adenomas can give rise to a variety of clinical disorders and surgery is often the primary treatment option. However, preoperative magnetic resonance imaging (MRI) does not always reliably identify the site of an adenoma. In ...

    Abstract Abstract Background Pituitary adenomas can give rise to a variety of clinical disorders and surgery is often the primary treatment option. However, preoperative magnetic resonance imaging (MRI) does not always reliably identify the site of an adenoma. In this setting molecular (functional) imaging (e.g. 11C-methionine PET/CT) may help with tumor localisation, although interpretation of these 2D images can be challenging. 3D printing of anatomicalal models for other indications has been shown to aid surgical planning and improve patient understanding of the planned procedure. Here, we explore the potential utility of four types of 3D printing using PET/CT and co-registered MRI for visualising pituitary adenomas. Methods A 3D patient-specific model based on a challenging clinical case was created by segmenting the pituitary gland, pituitary adenoma, carotid arteries and bone using contemporary PET/CT and MR images. The 3D anatomical models were printed using VP, MEX, MJ and PBF 3D printing methods. Different anatomicalal structures were printed in color with the exception of the PBF anatomical model where a single color was used. The anatomical models were compared against the computer model to assess printing accuracy. Three groups of clinicians (endocrinologists, neurosurgeons and ENT surgeons) assessed the anatomical models for their potential clinical utility. Results All of the printing techniques produced anatomical models which were spatially accurate, with the commercial printing techniques (MJ and PBF) and the consumer printing techniques (VP and MEX) demonstrating comparable findings (all techniques had mean spatial differences from the computer model of < 0.6 mm). The MJ, VP and MEX printing techniques yielded multicolored anatomical models, which the clinicians unanimously agreed would be preferable to use when talking to a patient; in contrast, 50%, 40% and 0% of endocrinologists, neurosurgeons and ENT surgeons respectively would consider using the PBF model. Conclusion 3D anatomical models of ...
    Keywords 3D printing ; Pituitary ; PET/CT ; MRI ; Cost analysis ; Clinical utility ; Medical physics. Medical radiology. Nuclear medicine ; R895-920
    Language English
    Publishing date 2021-08-01T00:00:00Z
    Publisher BMC
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  4. Article ; Online: Targeted Molecular Imaging in Adrenal Disease—An Emerging Role for Metomidate PET-CT

    Iosif A. Mendichovszky / Andrew S. Powlson / Roido Manavaki / Franklin I. Aigbirhio / Heok Cheow / John R. Buscombe / Mark Gurnell / Fiona J. Gilbert

    Diagnostics, Vol 6, Iss 4, p

    2016  Volume 42

    Abstract: Adrenal lesions present a significant diagnostic burden for both radiologists and endocrinologists, especially with the increasing number of adrenal ‘incidentalomas’ detected on modern computed tomography (CT) or magnetic resonance imaging (MRI). A key ... ...

    Abstract Adrenal lesions present a significant diagnostic burden for both radiologists and endocrinologists, especially with the increasing number of adrenal ‘incidentalomas’ detected on modern computed tomography (CT) or magnetic resonance imaging (MRI). A key objective is the reliable distinction of benign disease from either primary adrenal malignancy (e.g., adrenocortical carcinoma or malignant forms of pheochromocytoma/paraganglioma (PPGL)) or metastases (e.g., bronchial, renal). Benign lesions may still be associated with adverse sequelae through autonomous hormone hypersecretion (e.g., primary aldosteronism, Cushing’s syndrome, phaeochromocytoma). Here, identifying a causative lesion, or lateralising the disease to a single adrenal gland, is key to effective management, as unilateral adrenalectomy may offer the potential for curing conditions that are typically associated with significant excess morbidity and mortality. This review considers the evolving role of positron emission tomography (PET) imaging in addressing the limitations of traditional cross-sectional imaging and adjunctive techniques, such as venous sampling, in the management of adrenal disorders. We review the development of targeted molecular imaging to the adrenocortical enzymes CYP11B1 and CYP11B2 with different radiolabeled metomidate compounds. Particular consideration is given to iodo-metomidate PET tracers for the diagnosis and management of adrenocortical carcinoma, and the increasingly recognized utility of 11C-metomidate PET-CT in primary aldosteronism.
    Keywords metomidate ; nuclear medicine ; adrenal ; primary aldosteronism ; adrenocortical carcinoma ; Medicine (General) ; R5-920
    Subject code 610
    Language English
    Publishing date 2016-11-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

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