Radionuclide therapy

As radionuclide therapy (also Endoradiotherapie ) are therapies refer to operations where radionuclides are used in non-enclosed form. The most frequently used radionuclide therapies are radioiodine therapy and - by a large margin - radiosynoviorthesis . Radionuclide therapy is counted among the nuclear medicine therapies.

Principles of enrichment

The highest possible activity of the radionuclide used in the target tissue is desired in order to achieve a high and therapeutically effective focus dose there. At the same time, the radiation exposure for the tissue that has not been pathologically changed should be as low as possible. For this purpose, suitable enrichment mechanisms must be selected.

The radiopharmaceutical can - if it is not very diffusible - be introduced locally into a pre-existing cavity ( e.g. joints , pleura (pleura), peritoneum (peritoneum) or cysts ) (intracavitary therapy). In other therapies, the radiopharmaceutical enters the target tissue via metabolic processes, via coupling to receptors or specific binding of antibodies .

Nuclides used

In the early days, only natural radionuclides such as radium or thorium were available, the decay radiation of which had a proportion of high-energy beta and gamma rays that was unfavorable for near-field therapy. They were also used in ignorance or in disregard of the associated risks (see Peteosthor ). Today only or predominantly beta emitters are used, only in exceptional cases alpha emitters ( ²²⁴ Ra ). If the nuclide used also emits gamma radiation , this radiation does not contribute to the therapeutic effect, but can be used to create a scintigram to monitor the therapy . The bremsstrahlung of certain beta emitters can also be used for a scintigram.

The colloidal ¹⁹⁸ Au used from 1945 for injection into cavities (intracavitary therapy) was initially replaced by the pure beta emitter ³² P due to its unfavorable radiation properties . Other beta emitters such as ⁹⁰ Y , ⁸⁹ Sr , ¹⁸⁶ Re or ¹⁶⁹ Er were added later . For the radioiodine therapy , which has the highest specificity of the metabolic accumulation rates, only the beta emitter ¹³¹ I is predominantly used. For the other methods, either ¹³¹ I or ⁹⁰ Y is usually used.

List of radionuclide therapies

This alphabetical list is not exhaustive. The therapies that are frequently performed are highlighted in bold. The other therapies are partly out of date, experimental or reserved for a few centers. The colored highlighting is used to assign neighboring lines to one another.

Surname	indication	Enrichment Mechanism	Radiopharmaceutical	nuclide	Type of radiation	HWZ	annotation
MIBG therapy	Neuroendocrine tumors , especially pheochromocytoma	active uptake in neuroendocrine cells , storage in neurosecretory granules	Metaiodbenzylguanidine	131 I.	predominantly β emitter	8.02 days	see also MIBG scintigraphy
palliative therapy of skeletal metastases	Bone metastases	Incorporation in calcium phosphate	Strontium chloride	89 Sr	pure β radiator	50.6 days
			Yttrium citrate	90 Y	pure β radiator	2.67 days
palliative therapy of skeletal metastases	Bone metastases	Attachment to the bone surface	Bisphosphonates e.g. B. HEDP or EDTMP	186 Re	pure β radiator	3.72 days
				153 Sm	pure β radiator	1.93 days
peritoneal therapy	recurrent malignant ascites ( ascites )	Puncture of the abdominal cavity	Protein colloid	90 Y	pure β radiator	2.67 days
				32 P	pure β radiator	14.3 days
pleural therapy	recurrent malignant pleural effusion	Puncture of the pleural space	Protein colloid	90 Y	pure β radiator	2.67 days	Alternative: pleurodesis
				32 P	pure β radiator	14.3 days
Radioimmunotherapy	various cancers	specific antibody binding	Immunoconjugates	div.
Example: Ibritumomab-Tiuxetan	malignant lymphoma of B cells	specific antibody binding to CD20	Immunoconjugate of ibritumomab and tiuxetan	90 Y	pure β radiator	2.67 days
Radioiodine therapy	Thyroid autonomy , Graves' disease , goiter , thyroid cancer	active uptake in thyroid cells ( sodium iodide symporter ), incorporation into thyroid hormones (including thyroid peroxidase )	Sodium iodide	131 I.	predominantly β emitter	8.02 days	in many countries only possible as a stationary
Radiopeptide therapy	neuroendocrine tumors	specific binding to the somatostatin receptor	Edotreotide (DOTATOC)	90 Y	pure β radiator	2.67 days
Radiophosphorus therapy	Polycythemia vera , essential thrombocythemia	Incorporation into nucleic acids , incorporation into calcium phosphate	Dihydrogen phosphate or sodium phosphate	32 P	pure β radiator	14.3 days
Radiosynoviorthesis	Rheumatoid arthritis , activated osteoarthritis	Injection into the affected joint	Protein colloid	90 Y	pure β radiator	2.67 days	Nuclide depending on the size of the joint being treated; mostly possible on an outpatient basis
				186 Re	predominantly β emitter	3.72 days
				169 he	pure β radiator	9.40 days
224 Ra Radium Chloride Therapy	Ankylosing spondylitis (Bechterew's disease)		Radium chloride	224 ra	α emitters	3.66 days
Selective internal radiotherapy	Liver cell carcinoma , cholangiocellular carcinoma , liver metastases	selective angiography of the hepatic artery	Microspheres	90 Y	pure β radiator	2.67 days	see also transarterial chemoembolization
			Lipiodol	131 I.	predominantly β emitter	8.02 days

swell

• H. Schicha, M. Dietlein, K. Scheidhauer. Therapy with unsealed radioactive substances. In: U. Büll, H. Schicha, H.-J. Biersack, WH Knapp, Chr. Reiners, O. Schober . Nuclear medicine. Stuttgart, New York 2001. ISBN 3-13-128123-5

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