Thallium-201 tumor/cardiac ratio estimation of residual astrocytoma
Treatment of high-grade astrocytoma includes surgery, chemotherapy, and various methods of irradiation. Radiation therapy usually results in necrosis and edema around the primary tumor site. Contrast-enhanced computerized tomography (CT) and standard radionuclide imaging techniques are unable to reliably distinguish recurrent tumor from necrosis or edema since these images depict localization of contrast material or tracer, which primarily depends on blood-brain barrier breakdown. Thallium-201 (201Tl) appears to incorporate into viable tumor cells more rapidly than into normal brain cells. This report describes a new method to quantify the uptake of 201T1 in the tumor: the tumor-to-cardiac uptake ratio (T/C). Twenty-three 201T1 brain scans were performed on eight patients to differentiate recurrent viable high-grade astrocytoma from posttherapy changes. Planar images of the head and heart were obtained in order to calculate the ratio of tumor counts to cardiac counts. This ratio represents a numerical estimation of 201T1 uptake in the brain tumor relative to cardiac counts and is expressed as the T/C index. The T/C index correlated well with the clinical course in all eight patients. In general, however, CT suggested more extensive regrowth of tumor than the actual clinical status suggested. In one patient's course of radiological monitoring, tumor recurrence was detected by means of 201T1 imaging four months prior to its appearance on CT. In conclusion, when performed serially, the T/C index can provide an accurate estimate of residual tumor burden or recurrence, and detect and quantify viable tumor during therapy.
- Research Organization:
- Univ. of Michigan Medical Center, Ann Arbor (USA)
- OSTI ID:
- 7069495
- Journal Information:
- J. Neurosurg.; (United States), Vol. 68:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ASTROCYTOMAS
DIAGNOSIS
BRAIN
RADIOISOTOPE SCANNING
HEART
THALLIUM 201
UPTAKE
IMAGE PROCESSING
PATIENTS
BETA DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR SYSTEM
CENTRAL NERVOUS SYSTEM
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
GLIOMAS
HEAVY NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NEOPLASMS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PROCESSING
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
THALLIUM ISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics