Mayo clinic
SPECT scan: Why it's done - MayoClinic.com
"The most common uses of SPECT are to help diagnose or monitor brain disorders, heart problems and bone disorders"
Since you seem so interested to know what SPECT is for...let me cut/paste from medical resource:
SPECT scans — SPECT uses gamma ray emitting radioisotopes and a gamma camera to record data that a computer uses to construct two- or three-dimensional images of active tissue regions [89]. When applied to neuroimaging, SPECT relies on an injection of radioactive tracer, which is rapidly taken up by the brain but does not redistribute.
The most common tracers to image the CNS are 99mTc labeled hexamethylpropylene amine oxime (HMPAO) and ethyl cysteinate dimer (ECD). Uptake is nearly 100 percent complete within 30 to 60 seconds, reflecting cerebral blood flow at the time of injection [89].
A significant limitation of SPECT is its poor resolution (approximately 1 cm) compared to that of MRI [90]. (See 'Magnetic resonance imaging' above.)
SPECT applications —
SPECT may be useful for the evaluation of central nervous system (CNS) tumors, lymphoma, and epilepsy.
CNS tumors — SPECT has the potential to add valuable information to the diagnosis and management of certain types of CNS tumors. Radioactive tracers such as 99mTc-MIBI (sestamibi) are sensitive markers for brain tumors in children, particularly higher-grade astrocytomas [91]. Tumor types that take up 99mTc-MIBI include brainstem glioma, fibrillary astrocytoma, other low-grade astrocytomas, and glioblastoma multiforme. 99mTc-MIBI scans demonstrate changes in these tumors over time and correlate with histologic grade. In contrast, tumors demonstrated on MRI that are not visualized on 99mTc-MIBI SPECT include craniopharyngioma, medulloblastoma, and optic glioma [91].
CNS lymphoma — Thallium 201 (201-TI SPECT) is useful for the diagnosis of head and neck lymphoma. In particular, increased 201-TI uptake with co-localization of the lesion on MRI is highly specific for primary CNS lymphoma. (See "AIDS-related lymphomas: Primary central nervous system lymphoma", section on 'SPECT scanning'.)
Neuroblastoma — 123-I- metaiodobenzylguanidine (MIBG) is a useful tracer in the diagnosis of childhood neural crest tumors such as neuroblastoma, which can arise anywhere throughout the sympathetic nervous system. The uptake of 123-I-MIBG tracer within the tumor and its biodistribution can be used to determine if treatment with 131-I-MIBGm is warranted. (See "Clinical presentation, diagnosis, and staging evaluation of neuroblastoma", section on 'Radiologic evaluation'.)
Epilepsy — SPECT can be utilized in the diagnosis of seizures and is particularly important in surgical candidates. Ideally, both ictal and interictal SPECT should be obtained to localize the seizure focus; subtraction examinations can be performed off-line once the images are processed. Because cerebral blood flow changes are extremely rapid during the ictal phase, ictal injections should be performed within the first five to 10 seconds of seizure onset to obtain accurate localization. Timely injections during the ictal phase remain the main limitation of SPECT in children with epilepsy [92].
Ictal SPECT scans can be used to localize the epileptic focus in patients with epilepsy. Focal increased perfusion via SPECT occurs in up to 90 percent of patients with temporal lobe epilepsy [89]. Ictal patterns vary, but the most common pattern is unilateral temporal hyperperfusion with relatively decreased perfusion in other cortical areas in the ipsilateral and contralateral hemisphere. SPECT localization of epileptic focus has been reported in 70 to 90 percent of patients with frontal lobe epilepsy. Ictal SPECT studies also are useful in studying seizure spread. In temporal lobe epilepsy, ipsilateral basal ganglia hyperperfusion may be seen. In extra-temporal lobe epilepsy, the pattern of spread is more complex. In mesial frontal seizures, for example, the areas of activation often involve ipsilateral or bilateral basal ganglia and the contralateral cerebellar hemisphere.
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Radiation — Radiation dose is particularly important in children because radiation exposure from CT scanning appears to be associated with a small increased lifetime cancer risk [19,20]. In addition, there is a suggestion in the literature that
early radiation to the brain may impair long-term cognitive function [21,22]. Although pediatric CT accounts for approximately 15 percent of radiographic examinations, it contributes to an estimated 70 percent of the total radiation dose to the population [23,24].
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Now you know why i criticized Dr. Amen for (proudly) saying that he has scanned all his children and their dates with SPECT! That is just plain stupid!
But, i respect him as a businessman because he has found a niche to grow...and be very successful with deceiving people of what he can offer outside the medical standard of care.
