Methods of nuclear medicine in oncology

Scintigraphy

• 'Positive scintigraphy' - deposit accumulates radiopharmaceutical (hot deposit);
• 'negative scintigraphy' - deposit accumulates less (cold deposit);
• uses nuclides with a short half-life ( ^99m Tc - 6h, ¹¹¹ In - 67h, ⁶⁷ Ga - 3.3 days).

Skeletal scintigraphy

• Technetium-labeled diphosphonate complexes;
• the amount of accumulation depends on blood flow and osteoblast activity;
• display much earlier than X-ray;
• good for kidneys - lung cancer, breast cancer, prostate cancer, kidney cancer and bladder cancer;
• it is worse for osteolytic processes (myeloma), where there is only a reactive margin.

Liver and spleen scintigraphy

• Colloids trapped by RES, pathological deposits in liver appear as "cold";
• however, the defects were not less than 2 cm.

Thyroid scintigraphy

• Sodium pertechnetate.

Octreotide scintigraphy

• India-labeled octreotide (somatostatin analogue);
• detection of tumors with somatostatin receptors (gastrinoma, carcinoid, VIPom, small cell lung cancer, pheochromocytoma).

Immunoscintigraphy

• Radiolabelled Ig (against CEA, etc.).

Single photon emission tomography (SPECT)

• Spatial distribution of radiopharmaceuticals in tissue, more accurate assessment of shape and size;

• resolution less than CT;

• PET is considered more preferable.

Positron emission tomography (PET)

PET / CT pelvis: Increased metabolic activity in the lymph node (left) and near the sigmoid colon (right)

• Assessment of metabolic activity in tissues;

• uses positron emitters ( ¹⁵ O, ¹³ N, ¹¹ C, ¹⁸ F), have a very short half-life , must be produced on site ( 'cyclotron y' );

• only fluorine can be transported ( 'FDG - fluoroureoxyglucose' );

• FDG accumulation indicates metabolic activity (distinguishes active tumor from residual fibrotic tissues).

Source

• ws:Metody nukleární medicíny v onkologii