Radioactive pharmaceutical preparations ( eng. Radiopharmaceuticals ) are pharmaceutical preparations that contain an unstable isotope that makes these preparations radioactive . Radiation can be used either to assess the metabolism of an isotope-labeled substance in the body, or to oppress tissues that have absorbed the isotope. Designed for biomedical research, radioisotope diagnosis and treatment of various diseases, mainly for radiotherapy of malignant tumors . [one]
For diagnostic purposes, radioisotopes are used, which, when introduced into the body, participate in the studied types of metabolism or the studied activity of organs and systems, and can be registered using radiometric methods. Such radioactive preparations, as far as possible, have a short effective half-life and low-energy radiation that is poorly absorbed in the tissues, which causes a slight radiation load on the organism of the subject. [2]
The criterion for the selection of radioactive drugs intended for radiotherapy of malignant neoplasms is the possibility of creating the necessary therapeutic dose of ionizing radiation in the neoplasm with minimal impact on healthy tissues. This effect is achieved both by choosing the type and duration of exposure and by choosing the method of delivering the radiopharmaceutical to the target. Delivery is possible both through the body's metabolism with selective accumulation of a radioactive isotope in the tissues to be irradiated, and by surgical means in the form of granules, probes, application bands, etc. [2]
Content
Classification
Radioactive drugs are divided into open and closed [1] :
- In closed preparations, the radioactive material is enclosed in a protective coating or capsule to prevent radioactive contamination of the environment and contact with the radioactive compound of the patient and staff.
- In open preparations, direct contact of the radioactive substance with body tissues and the environment is carried out.
List of radioisotopes used
| Isotope | Half-life period [3] [4] | Type and energy of radiation [3] [4] [average] | Application [2] | |
|---|---|---|---|---|
| 11 C | 20.385 min | β + | 1982.1 keV [390 keV] | Diagnosis using positron emission tomography . Metabolic state of the heart, assessment of amino acid consumption ( methionine , leucine ) and protein synthesis, diagnosis of brain tumors, evaluation of the parathyroid metabolic state, metabolic rate of fatty acids in the myocardium |
| 13 N | 9.97 min | β + | 1200.3 keV | Diagnosis using positron emission tomography . Blood flow measurement, myocardial perfusion evaluation |
| 15 o | 122.24 seconds | β + | 1731.9 keV [735.28 keV] [5] | Diagnosis using positron emission tomography . Investigation of lung function, central and peripheral hemodynamics, etc. |
| 18 F | 109.771 min | β + | 633.5 keV | Diagnosis using positron emission tomography . Visualization of tumors of various localizations, assessment of glucose metabolism in the myocardium, lungs, brain, Alzheimer's disease diagnosis, diagnosis of diffuse Levy's Taurus disease, diagnosis of Parkinson's disease, localization of the epileptic focus. |
| 32 P | 14,262 days | β− | 1710.66 keV [694.9 keV] | Interstitial and intracavitary radiation therapy of tumors; treatment of polycythemia and related disorders. For the same purpose, 33 P can be applied. |
| 60 Co | 5.2714 years old | β− | 317.88 keV | in the treatment of tumors of the female genital organs, cancer of the mucous membrane of the mouth and lung, brain tumors, etc. |
| γ | 1173.237 keV 1332.501 keV | |||
| 85 Kr | 10,756 years | β− | 687.4 keV | investigation of lung function, central and peripheral hemodynamics, etc. |
| 90 Y [6] | 64.1 hours | β− | 2280.1 keV [933.7 keV] | for interstitial and intracavitary radiotherapy (in the treatment of tumors of the female genital organs, cancer of the mucous membrane of the mouth and lung, brain tumors, etc.) |
| 99m Tc | 6.01 hours | γ | 140.511 keV | Diagnosis using gamma cameras of brain tumors, the study of central and peripheral hemodynamics, etc .; examination of the lungs, liver, brain, etc. |
| 111 In [6] | 2.8047 days | γ | 171.28 keV 245.40 keV | examination of the lungs, liver, brain, etc. |
| 113m In [7] | 1.6582 hours | γ | 391.69 keV | liver research, etc. |
| 123 I | 13 hours | γ | 160 keV | Diagnosis using gamma cameras of the thyroid gland and the nervous system of the heart. |
| 125 I | 59.5 days | γ | 35 keV | Treatment of prostate oncology with brachytherapy . Diagnostics for long-term studies, where there is not enough iodine-123 lifetime. |
| 131 I [6] | 8.02070 days | β− | 606.3 keV [191.58 keV] | Treatment of iodine-absorbing metastases of malignant tumors of the thyroid gland. Associated treatment studies of iodine metabolism. |
| γ | 364.489 keV | |||
| 133 Xe [6] | 5,243 days | β− | 346.0 keV [100.5 keV] | investigation of lung function, central and peripheral hemodynamics, etc. |
| γ | 80,997 keV | |||
| 192 Ir | 73,827 days | β− | 672 keV (50.46%) | in the treatment of tumors of the female genital organs, cancer of the mucous membrane of the mouth and lung, brain tumors, etc. |
| 535 keV (43.55%) | ||||
| γ | 468.0688 keV 316,50618 keV | |||
| 308.45507 keV 295.9565 keV 316,50618 keV | ||||
| 198 Au | 2,69517 days | β− | 962 keV | examination of the lungs, liver, brain, etc .; for interstitial and intracavitary radiation therapy of tumors |
| γ | 411.80205 keV | |||
| 201 Tl | 3,038 days | γ | 919.50 keV | in ischemic heart disease - ischemia and myocardial infarction |
Notes
- ↑ 1 2 Bochkarev V.V. Radioactive drugs // Short medical encyclopedia . - 2nd ed. - M .: Soviet Encyclopedia, 1989.
- ↑ 1 2 3 Radioactive drugs - an article from the Great Soviet Encyclopedia .
- ↑ 1 2 Table of Nuclides (English) . Nuclear Data Evaluation Lab. (2000). The appeal date is December 29, 2007. Archived on February 25, 2012.
- 2 1 2 Chu SYF, Ekström LP and Firestone RB WWW Table of Radioactive Isotopes (English) (inaccessible link) . Nuclear Data Search. Version 2.0 . Lund / LBNL (02/28/1999). The appeal date was December 31, 2007. Archived February 25, 2012.
- ↑ Positrons almost instantaneously annihilate with the electrons of the surrounding matter, emitting two gamma quanta with an energy of 511 keV and an oppositely directed pulse.
- ↑ 1 2 3 4 Medical Isotopes (English) . MDS Nordion. The date of circulation is January 2, 2008. Archived on February 25, 2012.
- ↑ 113 In is a stable non-radioactive isotope.
Literature
- Saksonov P.P., Shashkov V.S., Sergeev P.V. Radiation pharmacology. - M .: Medicine, 1976.