The Principles of Nuclear Medicine
The term nuclear medicine may be defined as the use of atomic nuclei’s abilities and nuclear physical methods of measurement in medical diagnostics and therapie. Gamma radiation (Electromagnetic waves) is set free in the body during radioactive decay of radionuclides. It is capable of passing through thick tissue layers and may also be detected outside the body. There are radionuclides used in nuclear medicine that are an isotope of elements having a known distribution in the body, or can be built into chemical compounds (Biotracer) and into the natural metabolism.
Those radioactive atoms can be used in such small doses that there is no influence on cell metabolism at all, as the radiation exposure is very small. Thus examinations in nuclear medicine are so-called functioned examinations. Besides the advantage of a detecting abnormal changes, during examinations there often is a higher sensitivity than under normal procedures. An image illustration of corporal activity distribution is called a Scintigram, which is also possible as tomographic scintigraphy (using a Gamma-Camera). Using this method, a functioned-morphologic illustration in section technique can be created. This has a high information value about the dimension and extent of a disease, which becomes particularly important during follow-up therapy-controlling-examinations.
Processes in nuclear medicine are non-invasive, which means that examination substances are only injected intravenously no discomfort whatsever, so that the patient doesn´t feels.
Examples of diagnostics:
- Thyroid Gland
- Cardiac muscle perfusion (Myocardial-Scintigraphy) in rest and under stress
- Renal function diagnostics (Measure of side-divided renal functions)
- Bone Scintigraphy (Inflammation, Search for metastases, early fracture evidence)
- Brain blood circulation / perfusion
Case Study 1: Liver metastasis
The patient complained about an unclear weightloss, performance decrease in and nightly perspiration.
1.) Consultation: Sonography
Sonography of the abdomen detecting abnormal focuses. Suggestion to perform a CT.
2.) Computer Tomography
CT, Diagnosis: suspicious lesions
Using PET/CT the suspicious liver lesions were directly diagnosed as liver metastasis
The PET/CT examination directly showed in the very first procedure the primary tumour in the Colon transversum.
Histologic examinations of the OP-preparation: Poorly differentiated adenocarcinoma of the Colon transversum
Case Study 2: Epiglottis carcinoma with metastasis
A swelling in the right lateral. cervical triangle was operated. Operation, histology: Metastasis of a squamos epithilial carcinoma, unknown primary tumour: CUP-Syndrome.
Primary tumour in the areas of the Epiglottis with additional lymph node metastasis (reference to the following picture)
An ENT doctor (otorhinolaryngologist) performed an endoscopy because of the PET/CT with no pathological findings.
Only after consulation per telefone an OP was advised and performed.
The histological examination finding: To medium to low differentiated, invasive squamous epithelium carcinoma in the area of the laryngeal Epiglottis (right-sided) with a lymph node metastasis. Thus the primarius of the already known lympatic-metastasis was most probably found.