Parathyroid

• Primary hyperparathyroidism: condition in which one or more of the parathyroid glands makes too much PTH.
• Secondary hyperparathyroidism: condition of excessive secretion of parathyroid hormone (PTH) by the parathyroid glands in response to hypocalcemia
• Tertiary hyperparathyroidism: may be due to adenoma
• How do we perform parathyroid scintigraphy?

  Inject the 99mTc-MIBI material. (MIBI is absorbed only by an overactive parathyroid gland)
• Dual phase technique of parathyroid scintigraphy?

  1. Thyroid phase – initial early image is obtained 10-15min after the injection; 99mTc-MIBI is rapidly concentrated in the thyroid gland
  2. Parathyroid phase – 1.5-3h after the injection; emphasizes the differential washout of 99mTc-MIBI from abnormal parathyroid glands
• Two isotope technique of parathyroid scintigraphy?

  • Optional technique which includes the acquisition of right and left anterior oblique images to better depict the relationship of the parathyroid glands and thyroid gland.
  • 99mTc pertechnetate can be administered w/ sestamibi
• can dual phase technique and two isotope technique be combined with each other?

  yes
• Indications of parathyroid scintigraphy?

  • localization of adenoma
  • Primary hyperparathyroidism
  • secondary hyperparathyroidism
  • tertiary hyperparathyroidism
  • carcinoma
• Findings of parathyroid scintigraphy

  • norm = no activity
  • adenoma = hot nodule behind thyroid / mediastinum
  • high MIBI affinity = Oxyphil parathyroid adenomas
  • some MIBI affinity = Chief cell adenomas
  • no MIBI affinity = Clear cell parathyroid adenomas
• False positive finding in parathyroid scintigraphy?

  • Thyroid adenoma
  • Patient movement (in case of subtraction)
  • Lymphoma, Sarcoidosis
• False negative findings in parathyroid scintigraphy?

  • too small adenoma
  • clear cell parathyroid adenoma
• What is the subtraction technique in parathyroid scintigraphy?

  Imaging with 99mTc-pertechnetate and later/next day with 99mTc-MIBI, then image subtraction (by computer).
• What does minimally invasive radio-guided parathyroidectomy mean?

  Focused exploration/removal of a single abnormal parathyroid gland, directed by pre-operative localizing studies, performed through an incision measuring 2.5 cm (1 in) or less.
• Radio-guided parathyroidectomy procedure?

  1. Make the overproducing parathyroid gland radioactive
  2. Operate only where necessary
  3. Use a miniature hand-held radiation detecting probe to find the radioactive parathyroid.
  4. Remove the radioactive parathyroid tumor
  5. Measure the radioactivity in the parathyroid tumor to help make sure that the patient is cured of their disease.
• What are the basic benefits of radio-guided parathyroidectomy?

  • quick
  • high cure rate
  • low complication rate
  • no stitches to remove
  • can be performed on all ages
• How we call generally the radionucleotide in surgery? What device we use for that?

  Micro-gamma camera or probes, for laparoscopic operation
• what method of imaging is shown?

  subtraction technique