*4.3.1 Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi*

The rationale that stands behind dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi, is that 99mTc-sestamibi accumulates in both, thyroid gland and hyperfunctioning parathyroid glands, while 99mTc-pertechnetate uptakes only in the thyroid. First thyroid specific radionuclide 99mTc-pertechnetate

#### **Figure 7.**

*(а) Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi. Upper image on the left-image of thyroid gland obtained with 99mTc-pertehnetat. Upper image on the right an image obtained with 99mTc sestamibi (arrow). Lower image. Subtractional image showing a focus of a residual activity (arrow) in upper back part of the left thyroid lobe consistent with left parathyroid adenoma and (b) (same patient) dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi. Early SPECT images showing an area of intense uptake located dorsally and cranially of the left thyroid lobe.*

**57**

**Figure 8.**

*Parathyroid Scintigraphy*

*DOI: http://dx.doi.org/10.5772/intechopen.90341*

is injected and at 30th min images are obtained. Afterwards, while the patient is still under the detector, second radionuclide 99mTc sestamibi with dual accumulation is applied and a second set of images on the 20th min are obtained. Later images are subtracted digitally from the first set of images and if a focus of residual activity on the subtractional images is detected, a hyperfunctioning parathyroid gland is supposed. The combination with early SPECT can improve sensitivity (**Figure 7a** and **b**). The subtraction could be of help, when the patients had undergone surgery of the thyroid, but some thyroid parenchyma is still present. This method is important

in the presence of more than one abnormal parathyroid gland.

Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi combined with SPECT in a 51 years old man with MEN-type 1

*(а) Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi. Subtractional image showing two areas of intense uptake consistent with two parathyroid adenomas and (b) SPECT images* 

*showing an area of intense uptake located dorsally and caudally of the right thyroid lobe.*

### *Parathyroid Scintigraphy DOI: http://dx.doi.org/10.5772/intechopen.90341*

*Medical Isotopes*

*sestamibi*

**4.3 Dual-isotope subtractional scintigraphy with: 99mTc-pertehnetat/99mTc** 

The rationale that stands behind dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi, is that 99mTc-sestamibi accumulates in both, thyroid gland and hyperfunctioning parathyroid glands, while 99mTc-pertechnetate uptakes only in the thyroid. First thyroid specific radionuclide 99mTc-pertechnetate

*(а) Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi. Upper image on the left-image of thyroid gland obtained with 99mTc-pertehnetat. Upper image on the right an image obtained with 99mTc sestamibi (arrow). Lower image. Subtractional image showing a focus of a residual activity (arrow) in upper back part of the left thyroid lobe consistent with left parathyroid adenoma and (b) (same patient) dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi. Early SPECT images showing* 

*an area of intense uptake located dorsally and cranially of the left thyroid lobe.*

*4.3.1 Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc* 

**sestamibi or 99mTc-pertehnetat/99mTc-tetrofosmin**

**56**

**Figure 7.**

is injected and at 30th min images are obtained. Afterwards, while the patient is still under the detector, second radionuclide 99mTc sestamibi with dual accumulation is applied and a second set of images on the 20th min are obtained. Later images are subtracted digitally from the first set of images and if a focus of residual activity on the subtractional images is detected, a hyperfunctioning parathyroid gland is supposed. The combination with early SPECT can improve sensitivity (**Figure 7a** and **b**).

The subtraction could be of help, when the patients had undergone surgery of the thyroid, but some thyroid parenchyma is still present. This method is important in the presence of more than one abnormal parathyroid gland.

Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi combined with SPECT in a 51 years old man with MEN-type 1

#### **Figure 8.**

*(а) Dual-isotope subtractional scintigraphy with 99mTc-pertehnetat/99mTc sestamibi. Subtractional image showing two areas of intense uptake consistent with two parathyroid adenomas and (b) SPECT images showing an area of intense uptake located dorsally and caudally of the right thyroid lobe.*

#### *Medical Isotopes*

syndrome—pheochromocytoma, parathyroid adenoma and prolactinoma, who had previously undergone thyroid (subtotal thyroidectomy) and parathyroid (left upper parathyroid gland) surgery. Subtractional images (**Figure 8a**) and early SPECT images (**Figure 8b**) show two areas of intense uptake located below the remnants of the both thyroid lobes. SPECT images show that the lesion below the right thyroid lobe was located also adjacent to the back part of the right thyroid lobe.

In some cases, obtaining late images could also be of help. Combining dualisotope, 99mTc-pertehnetat/99mTc sestamibi, subtractional scintigraphy with SPECT, and also recording late planar images on the 120th min (late phase) would improve sensitivity (**Figures 9** and **10**).
