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Image Acquisition Protocols
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
An example of the use of dual isotope imaging is for the diagnosis of parathyroid adenoma [1]. The parathyroids are small glands situated behind the thyroid. A parathyroid adenoma is a benign tumour on one of these glands that can result in the over expression of the parathyroid hormone. There is not a single radiopharmaceutical specific to parathyroid imaging. However, Thallium-201 is taken up by both parathyroid tissue and the thyroid. Unfortunately, as the parathyroid glands are situated behind the thyroid it is very difficult to distinguish the two on a single 201Tl planar acquisition. Technetium-99m pertechnetate may also be administered in combination with the 201Tl. The 99mTc is trapped by functioning thyroid tissue, but not the adenoma. A subtraction of 99mTc events from 201Tl events therefore results in an image of just the adenoma. Typical imaging parameters for this test are described in Table 15.2 with example 201Tl, 99mTc and subtraction images shown in Figure 15.9.
Radiopharmaceuticals for Diagnostics
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Jim Ballinger, Jacek Koziorowski
The parathyroid glands, located adjacent to the thyroid, regulate the body’s use of calcium. Parathyroid adenoma is a benign condition causing hyperparathyroidism, usually resulting in elevated blood calcium levels, which is best treated by minimally invasive surgery. Imaging plays an important role in guiding surgery. Most commonly used now is the myocardial perfusion agent, 99mTc-sestamibi, which accumulates in both the thyroid and parathyroid glands but is only retained in the parathyroid glands. The mechanism of accumulation of 99mTc-sestamibi is not fully understood but is believed to be related to high mitochondrial activity. Two imaging approaches are taken. One uses early and late imaging (15 min and 2 h) following injection of 99mTc-sestamibi. Relative focal increase in the parathyroid glands (as the tracer washes out of the thyroid) is indicative of adenoma. An alternative approach uses a second, thyroid-specific tracer, such as 99mTc-pertechnetate or 123I-iodide, to allow subtraction of thyroid activity for better definition of the parathyroid glands. In either case, SPECT or SPECT/CT imaging is useful to provide the surgeon with a roadmap [29].
Paper 3
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
Brown tumours are historically most commonly attributed to primary hyperparathyroidism, of which the most frequent cause is a parathyroid adenoma. This could be detected with a nuclear medicine 99-Tc-MIBI scan which should reveal the parathyroid adenoma. A pertechnetate thyroid scan investigating for a parathyroid adenoma (e.g. in answer A) would detect a region of decreased tracer uptake compared to the thyroid, rather than increased uptake.
Skin hypersensitivity following application of tissue adhesive (2-octyl cyanoacrylate)
Published in Baylor University Medical Center Proceedings, 2021
Raymond P. Shupak, Sid Blackmore, Roderick Y. Kim
Two women presented for evaluation of primary hyperparathyroidism. Workup included serum parathyroid hormone, calcium levels, and a nuclear medicine parathyroid SPECT scan (Table 1). Both underwent an uncomplicated transcervical approach to their parathyroid adenoma. Closure was undertaken in a standard layered fashion, followed by 4-0 Monocryl running subcuticular closure with topical application of Dermabond. The first patient experienced significant pain, pruritus, and swelling associated with the surgical incision (Figure 1). She was treated with intravenous diphenhydramine and steroids, and an unsuccessful attempt was made to remove the skin adhesive, despite following the manufacturer’s recommendations. In the second case, the patient denied pruritus or pain associated with the reaction. Postoperatively, skin sloughing, necrosis, and superficial infection were observed, requiring a course of antibiotics. Local wound care was prescribed until resolution. She refused any additional revision surgery (Figure 2).
Primary hyperparathyroidism associated with non-Hodgkin lymphoma: a case report and literature review
Published in Postgraduate Medicine, 2020
Yuanyuan Deng, Jiao Wang, Honghong Liu, Jianying Liu, Jixiong Xu
Primary hyperparathyroidism causes hypercalcemia through excessive secretion of PTH. NHL produces hypercalcemia mainly through two mechanisms: (1) local osteolytic hypercalcemia: tumor cells cause hypercalcemia through bone metastasis, bone destruction, bone calcium directly into the blood, and secretion of cytokines with osteolytic activity such as IL-1, IL-6, TNF-α,etc. (2) humoral hypercalcemia of malignancy: the main mechanism involves that lymphoma cells elicits parathyroid hormone-related protein (PTHrP) or 1-α-hydroxylase [7]. Some studies have also shown that certain malignant lymphomas can cause hypercalcemia by producing 1,25-dihydroxyvitamin D or stimulating macrophages to produce 1-alpha hydroxylase [5,17] . In this case, the patient presented clinical manifestations of high calcium. After removal of the parathyroid adenoma, the patient’s serum calcium level returned to normal, but PTH was low. Although PTH suppression is found in patients with hypercalcemia due to diffuse bone metastasis (in a feed-back mechanism), high-functioning adenomas may also inhibit normal parathyroid function. Combined with that the patients did not have any clinical manifestations of pain and serum calcium was normal after repeated examinations. Therefore, the low PTH may be caused by temporary suppression of normal parathyroid function after surgery. We consider that this case of hypercalcemia is caused only by primary hyperparathyroidism.
Incidence of and risk factors for post-parathyroidectomy hungry bone syndrome in patients with secondary hyperparathyroidism
Published in Renal Failure, 2020
Kittrawee Kritmetapak, Sawinee Kongpetch, Wijittra Chotmongkol, Yutapong Raruenrom, Sakkarn Sangkhamanon, Chatlert Pongchaiyakul
All resected parathyroid gland specimens were reviewed by an experienced pathologist to identify the presence of parathyroid hyperplasia or adenoma. Parathyroid hyperplasia was defined as an adaptive increase in parathyroid parenchymal mass resulting from proliferation of chief, oxyphil, and transitional cells in multiple parathyroid glands. Parathyroid adenoma was defined as encapsulated monoclonal cell proliferation composed predominantly of chief cells and involving a single parathyroid gland. HBS was defined as the requirement of intravenous calcium administration due to clinical symptoms of hypocalcemia (e.g. tingling, muscle spasms, tetany) and/or a rapid postoperative reduction in serum calcium concentration to less than 8.4 mg/dL during the first 72 h after parathyroidectomy, despite optimization of supportive therapy including oral calcium and vitamin D supplementation [21–23].