Technetium (99mTc) sestamibi

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Technetium (99mTc) sestamibi
Tc CNCH2CMe2(OMe) 6Cation.png
Clinical data
Trade names Cardiolite
License data
Routes of
administration 		Intravenous
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability NA
Protein binding 1%
Metabolism Nil
Elimination half-life Variable
Excretion Fecal (33%) and renal (27%)
Identifiers
  • Hexakis(2-methoxy-2-methylpropylisonitrile)
    technetium (99mTc)
CAS Number
PubChem CID
ChemSpider
UNII
KEGG
ChEBI
CompTox Dashboard (EPA)
Chemical and physical data
Formula C36H66N6O6Tc
Molar mass 777 g·mol−1
3D model (JSmol)
  • [99Tc-5](C#[N+]CC(C)(C)OC)(C#[N+]CC(C)(C)OC)(C#[N+]CC(C)(C)OC)(C#[N+]CC(C)(C)OC)(C#[N+]CC(C)(C)OC)C#[N+]CC(C)(C)OC
   (verify)

Technetium (99mTc) sestamibi (INN) (commonly sestamibi; USP: technetium Tc 99m sestamibi; trade name Cardiolite) is a pharmaceutical agent used in nuclear medicine imaging. The drug is a coordination complex consisting of the radioisotope technetium-99m bound to six (sesta=6) methoxyisobutylisonitrile (MIBI) ligands. The anion is not defined. The generic drug became available late September 2008. A scan of a patient using MIBI is commonly known as a "MIBI scan".

Contents

Sestamibi is taken up by tissues with large numbers of mitochondria and negative plasma membrane potentials. [1] Sestamibi is mainly used to image the myocardium (heart muscle). It is also used in the work-up of primary hyperparathyroidism to identify parathyroid adenomas, for radioguided surgery of the parathyroid and in the work-up of possible breast cancer.

Cardiac imaging (MIBI scan)

A MIBI scan or sestamibi scan is now a common method of cardiac imaging. Technetium (99mTc) sestamibi is a lipophilic cation which, when injected intravenously into a patient, distributes in the myocardium proportionally to the myocardial blood flow. Single photon emission computed tomography (SPECT) imaging of the heart is performed using a gamma camera to detect the gamma rays emitted by the technetium-99m as it decays.

Two sets of images are acquired. For one set, 99mTc MIBI is injected while the patient is at rest and then the myocardium is imaged. In the second set, the patient is stressed either by exercising on a treadmill or pharmacologically. The drug is injected at peak stress and then imaging is performed. The resulting two sets of images are compared with each other to distinguish ischemic from infarcted areas of the myocardium. This imaging technique has a sensitivity of around 90%. [2] Resting images are useful only for detecting tissue damage, while stress images will also provide evidence of coronary artery (ischemia) disease. [3] [4]

With dipyridamole (Persantine MIBI scan)

When combined with the drug dipyridamole, a brand name of which is Persantine, a MIBI scan is often referred to as a Persantine MIBI scan.

Parathyroid imaging

In primary hyperparathyroidism, one or more of the four parathyroid glands either develops a benign tumor called an adenoma or undergoes hyperplasia as a result of homeostatic dysregulation. The parathyroid gland takes up 99mTc MIBI following an intravenous injection, and the patient's neck is imaged with a gamma camera to show the location of all glands. A second image is obtained after a washout time (approximately 2 hours), and mitochondria in the oxyphil cells of the abnormal glands retaining the 99mTc are seen with the gamma camera. This imaging method will detect 75 to 90 percent of abnormal parathyroid glands in primary hyperparathyroidism. An endocrine surgeon can then perform a focused parathyroidectomy (less invasive than traditional surgery) to remove the abnormal gland.

Radioguided surgery of the parathyroids

Following administration, 99mTc MIBI collects in overactive parathyroid glands. During surgery, the surgeon can use a probe sensitive to gamma rays to locate the overactive parathyroid before removing it. [5]

Thyroid imaging

Several case reports have demonstrated that 99mTc MIBI scan may be useful to differentiae the sub-type of amiodarone-induced thyrotoxicosis. Lack of MIBI uptake in the thyroid is compatible with a form of thyroiditis (type-2 AIT) which may respond to treatment with steroids. [6]

Breast imaging

The drug is also used in the evaluation of breast nodules. Malignant breast tissues concentrate 99mTc MIBI to a much greater extent and more frequently than benign disease. As such, limited characterization of breast anomalies is possible. Scintimammography has a high sensitivity and specificity for breast cancer, both more than 85%. [7]

More recently, breast radiologists administer lower doses of 99mTc sestamibi (approximately 150–300 MBq or 4–8 mCi) for Molecular Breast Imaging (MBI) scans which results in a high sensitivity (91%) and high specificity (93%) for breast cancer detection. [8] It however carries a greater risk of causing cancer, making it not appropriate for general breast cancer screening in patients. [9]

The last reference listed[ which? ] refers to a 740-megabecquerel (20-millicurie) dose, which is given with the Dilon single-head system, which requires a higher dose since only one camera is utilized (meaning the camera needs to be able to see through more tissue). A 150–300 MBq (4–8 mCi) dose, which is used in the other two commercially available MBI systems is essentially equivalent to a mammogram (150 MBq or 4 mCi) or a tomosynthesis exam (300 MBq or 8 mCi). [10]

In order to keep the radiation doses to patients as low as reasonably achievable, MBI is usually limited to women with dense breast tissue, where the medical benefit of the scan outweighs the potential risk of radiation exposure. For the same reason, the administered activity is kept low. This can potentially result in noisy images, which in turn causes inconclusive mammograms. Researchers continue to devote their time to improving the technology, changing scan parameters, and reducing dose to patients. [11]

Related Research Articles

<span class="mw-page-title-main">Single-photon emission computed tomography</span> Nuclear medicine tomographic imaging technique

Single-photon emission computed tomography is a nuclear medicine tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera, but is able to provide true 3D information. This information is typically presented as cross-sectional slices through the patient, but can be freely reformatted or manipulated as required.

<span class="mw-page-title-main">Nuclear medicine</span> Medical specialty

Nuclear medicine or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is "radiology done inside out" because it records radiation emitted from within the body rather than radiation that is transmitted through the body from external sources like X-ray generators. In addition, nuclear medicine scans differ from radiology, as the emphasis is not on imaging anatomy, but on the function. For such reason, it is called a physiological imaging modality. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) scans are the two most common imaging modalities in nuclear medicine.

<span class="mw-page-title-main">Scintigraphy</span> Diagnostic imaging test in nuclear medicine

Scintigraphy, also known as a gamma scan, is a diagnostic test in nuclear medicine, where radioisotopes attached to drugs that travel to a specific organ or tissue (radiopharmaceuticals) are taken internally and the emitted gamma radiation is captured by gamma cameras, which are external detectors that form two-dimensional images in a process similar to the capture of x-ray images. In contrast, SPECT and positron emission tomography (PET) form 3-dimensional images and are therefore classified as separate techniques from scintigraphy, although they also use gamma cameras to detect internal radiation. Scintigraphy is unlike a diagnostic X-ray where external radiation is passed through the body to form an image.

<span class="mw-page-title-main">Radionuclide angiography</span> Nuclear medicine imaging the ventricles of the heart

Radionuclide angiography is an area of nuclear medicine which specialises in imaging to show the functionality of the right and left ventricles of the heart, thus allowing informed diagnostic intervention in heart failure. It involves use of a radiopharmaceutical, injected into a patient, and a gamma camera for acquisition. A MUGA scan involves an acquisition triggered (gated) at different points of the cardiac cycle. MUGA scanning is also called equilibrium radionuclide angiocardiography, radionuclide ventriculography (RNVG), or gated blood pool imaging, as well as SYMA scanning.

<span class="mw-page-title-main">Pertechnetate</span> Chemical compound or ion

The pertechnetate ion is an oxyanion with the chemical formula TcO−
4. It is often used as a convenient water-soluble source of isotopes of the radioactive element technetium (Tc). In particular it is used to carry the 99mTc isotope which is commonly used in nuclear medicine in several nuclear scanning procedures.

<span class="mw-page-title-main">Bone scintigraphy</span> Nuclear medicine imaging technique

A bone scan or bone scintigraphy is a nuclear medicine imaging technique of the bone. It can help diagnose a number of bone conditions, including cancer of the bone or metastasis, location of bone inflammation and fractures, and bone infection (osteomyelitis).

Technetium (99mTc) sulesomab is a radio-pharmaceutical composed of anti-human mouse monoclonal antibody that targets the granulocyte associated NCA-90 cell antigen and a conjugated technetium-99m radionuclide. After intravenous administration, Leukoscan enables sensitive and specific whole body measurement of granulocyte infiltration and activation by gamma camera imaging of 99mTc-antibody bound cells. Total clearance of LeukoScan from blood samples after administration and imaging has been reported at 48 hour time points indicating limited retention of the agent in circulation

<span class="mw-page-title-main">Technetium-99m</span> Metastable nuclear isomer of technetium-99

Technetium-99m (99mTc) is a metastable nuclear isomer of technetium-99, symbolized as 99mTc, that is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used medical radioisotope in the world.

Technetium (99mTc) arcitumomab is a drug used for the diagnostic imaging of colorectal cancers, marketed by Immunomedics. It consists of the Fab' fragment of a monoclonal antibody and a radionuclide, technetium-99m.

<span class="mw-page-title-main">Myocardial perfusion imaging</span> Nuclear medicine imaging method

Myocardial perfusion imaging or scanning is a nuclear medicine procedure that illustrates the function of the heart muscle (myocardium).

<span class="mw-page-title-main">Molecular breast imaging</span>

Molecular breast imaging (MBI), also known as scintimammography, is a type of breast imaging test that is used to detect cancer cells in breast tissue of individuals who have had abnormal mammograms, especially for those who have dense breast tissue, post-operative scar tissue or breast implants.

<span class="mw-page-title-main">Octreotide scan</span> Type of medical imaging

An octreotide scan is a type of SPECT scintigraphy used to find carcinoid, pancreatic neuroendocrine tumors, and to localize sarcoidosis. It is also called somatostatin receptor scintigraphy (SRS). Octreotide, a drug similar to somatostatin, is radiolabeled with indium-111, and is injected into a vein and travels through the bloodstream. The radioactive octreotide attaches to tumor cells that have receptors for somatostatin. A gamma camera detects the radioactive octreotide, and makes pictures showing where the tumor cells are in the body, typically by a SPECT technique. A technetium-99m based radiopharmaceutical kit is also available.

Perfusion is the passage of fluid through the lymphatic system or blood vessels to an organ or a tissue. The practice of perfusion scanning is the process by which this perfusion can be observed, recorded and quantified. The term perfusion scanning encompasses a wide range of medical imaging modalities.

<span class="mw-page-title-main">Parathyroid adenoma</span> Medical condition

A parathyroid adenoma is a benign tumor of the parathyroid gland. It generally causes hyperparathyroidism; there are very few reports of parathyroid adenomas that were not associated with hyperparathyroidism.

<span class="mw-page-title-main">Parathyroid carcinoma</span> Medical condition

Parathyroid carcinoma is a rare cancer resulting in parathyroid adenoma to carcinoma progression. It forms in tissues of one or more of the parathyroid glands.

Technetium (<sup>99m</sup>Tc) tetrofosmin Chemical compound

Technetium (99mTc) tetrofosmin is a drug used in nuclear medicine cardiac imaging. It is sold under the brand name Myoview. The radioisotope, technetium-99m, is chelated by two 1,2-bis[di-(2-ethoxyethyl)phosphino]ethane ligands which belong to the group of diphosphines and which are referred to as tetrofosmin.

<span class="mw-page-title-main">Parathyroid disease</span> Medical condition

Many conditions are associated with disorders of the function of the parathyroid gland. Some disorders may be purely anatomical resulting in an enlarged gland which will raise concern. Such benign disorders, such as parathyroid cyst, are not discussed here. Parathyroid diseases can be divided into those causing hyperparathyroidism, and those causing hypoparathyroidism.

<span class="mw-page-title-main">Gamma probe</span>

A gamma probe is a handheld device containing a scintillation counter for intraoperative use following injection of a radionuclide to locate sentinel lymph nodes by their radioactivity. It is used primarily for sentinel lymph node mapping and parathyroid surgery. Gamma probes are also used for RSL to locate small and non-palpable breast lesions.

<span class="mw-page-title-main">Sestamibi parathyroid scan</span> Procedure in nuclear medicine

A sestamibi parathyroid scan is a procedure in nuclear medicine which is performed to localize parathyroid adenoma, which causes Hyperparathyroidism. Adequate localization of parathyroid adenoma allows the surgeon to use a minimally invasive surgical approach.

A sestamibi scan is a medical imaging technique using gamma rays from the radioactive decay of the manmade compound Technetium (99mTc) sestamibi to penetrate muscle and other tissue to view their condition and function. It may refer specifically to:

References

  1. ↑ Rizk TH, Nagalli S (5 July 2020). "Technetium (99mTc) Sestamibi". StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. PMID   31985941.
  2. ↑ Underwood SR, Anagnostopoulos C, Cerqueira M, Ell PJ, Flint EJ, Harbinson M, et al. (February 2004). "Myocardial perfusion scintigraphy: the evidence". European Journal of Nuclear Medicine and Molecular Imaging. 31 (2): 261–291. doi:10.1007/s00259-003-1344-5. PMC   2562441 . PMID   15129710.
  3. ↑ Gorlin R, Brachfeld N, Macleod C, Bopp P (May 1959). "Effect of nitroglycerin on the coronary circulation in patients with coronary artery disease or increased left ventricular work". Circulation. 19 (5): 705–718. doi: 10.1161/01.CIR.19.5.705 . PMID   13652363.
  4. ↑ Ignatavicius DD (2015). "Assessment of the Cardiovascular System". In Ignatavicius DD, Workman ML (eds.). Medical-surgical Nursing: Patient-centered Collaborative Care. Elsevier Health Sciences. p. 646. ISBN   9781455772551.
  5. ↑ Untch BR, Barfield ME, Bason J, Olson JA (December 2007). "Minimally invasive radio-guided surgery for primary hyperparathyroidism". Annals of Surgical Oncology. 14 (12): 3401–3402. doi:10.1245/s10434-007-9519-0. PMID   17899291. S2CID   11371876.
  6. ↑ Itzkovich D, Ben-Haim S, Godefroy J, Stokar J (2023). "99mTc MIBI Scintigraphy for Classification of Amiodarone-induced Thyrotoxicosis". The Journal of Clinical Endocrinology & Metabolism Case Reports. 1. doi: 10.1210/jcemcr/luac011 . PMC   10578384 . S2CID   254358222.
  7. ↑ Liberman M, Sampalis F, Mulder DS, Sampalis JS (July 2003). "Breast cancer diagnosis by scintimammography: a meta-analysis and review of the literature". Breast Cancer Research and Treatment. 80 (1): 115–126. doi:10.1023/A:1024417331304. PMID   12889605. S2CID   10769269.
  8. ↑ Rhodes DJ, Hruska CB, Phillips SW, Whaley DH, O'Connor MK (January 2011). "Dedicated dual-head gamma imaging for breast cancer screening in women with mammographically dense breasts". Radiology. 258 (1): 106–118. doi:10.1148/radiol.10100625. PMID   21045179. S2CID   34145938.
  9. ↑ Moadel RM (May 2011). "Breast cancer imaging devices". Seminars in Nuclear Medicine. 41 (3): 229–241. doi:10.1053/j.semnuclmed.2010.12.005. PMID   21440698.
  10. ↑ O'Connor MK, Li H, Rhodes DJ, Hruska CB, Clancy CB, Vetter RJ (December 2010). "Comparison of radiation exposure and associated radiation-induced cancer risks from mammography and molecular imaging of the breast". Medical Physics. 37 (12): 6187–6198. Bibcode:2010MedPh..37.6187O. doi:10.1118/1.3512759. PMC   2997811 . PMID   21302775.
  11. ↑ O'Connor MK, Hruska CB, Weinmann A, Manduca A, Rhodes DJ (2010). "Development of radiation dose reduction techniques for cadmium zinc telluride detectors in molecular breast imaging". In Doty FP, Barber HB, Roehrig H, Schirato RC (eds.). Penetrating Radiation Systems and Applications XI. Vol. 7806. Proc SPIE. pp. 7–21. doi:10.1117/12.864649. S2CID   121649895 . Retrieved 10 December 2013.
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