2.1 Interventional Radiologist
2.1 Interventional Radiologist
Definition and Purpose:
Interventional radiologists are physicians specialized in treating diseases using minimally invasive techniques involving radiation.
The controlled use of radioisotopes has led to significant advancements in medical diagnosis and treatment.
Advantages of Interventional Radiology:
Many conditions that traditionally required lengthy and traumatic surgeries can now be treated non-surgically, which brings several benefits:
Reduced cost.
Lower levels of pain.
Shorter length of hospital stay.
Faster recovery times for patients.
Example Case - Liver Tumors:
Historically, patients with one or more tumors in the liver had limited treatment options: surgery or chemotherapy.
Challenges with these methods:
Some liver tumors may be difficult to access surgically.
Surgeries may require excessive removal of liver tissue.
Chemotherapy can be highly toxic to the liver, and certain tumors do not respond well to it.
Treatment Method - Radioembolization:
An interventional radiologist can treat difficult liver tumors by disrupting their blood supply, essential for tumor growth.
Procedure Steps:
The radiologist accesses the liver through a fine needle inserted into one of the patient's blood vessels.
Tiny radioactive "seeds" are then inserted into the blood vessels supplying the tumors.
The radiation emitted from these seeds destroys blood vessels and directly kills tumor cells in the treatment area.
Role of Radioisotopes in Imaging:
Radioisotopes emit subatomic particles detectable by imaging technologies.
A notable use of radioisotopes in medicine is the positron emission tomography (PET) scanner.
Function of PET Scan:
It detects activity in the body after a small injection of radioactive glucose, which is a vital energy source for cells.
By revealing which tissues take up the most glucose, PET scanners can identify metabolically active tissues, highlighting potential cancerous masses that consume glucose rapidly.
Figure 2.6 - PET Scan Analysis:
PET highlights areas of high glucose use indicative of cancerous tissue.
A sample image from a PET scan shows sites of metastatic spread from a primary tumor.
The Behavior of Electrons
Atoms in the Human Body:
Atoms do not exist as independent entities; they react with other atoms to form and break down complex substances.
Understanding anatomy and physiology requires grasping the interactions of atoms, focusing on electron behavior.
Electron Shells:
Electrons do not follow rigid orbits around an atom’s nucleus but remain within regions of space known as electrons shells.
Definition of Electron Shell:
An electron shell is a layer of electrons surrounding the nucleus at a specific energy level.
Each atom may have between one to five electron shells.
All shells hold a maximum of eight electrons, except the first shell, which can hold two.
Atom Examples Based on Electron Configuration:
Hydrogen and Helium:
Hydrogen has 1 electron (1st shell).
Helium has 2 electrons (1st shell, fully filled).
Lithium (Li, atomic number 3):
Has 3 electrons: 2 fill the first shell; the 3rd goes to the 2nd shell.
Carbon:
6 electrons: fills its first shell and half-fills its second shell.
Neon (Ne):
10 electrons: fully fills its two shells.
Reactivity and Stability of Atoms:
The principal factor governing an atom’s reactivity is its valence shell, or outermost shell.
Definition of Valence Shell:
An atom's outermost electron shell that determines its chemical reactivity.
Reactive Atom:
If the valence shell is not full, the atom is reactive and seeks to fill it.
Example: Hydrogen, with one electron, will react with other atoms to stabilize its valence shell.
Octet Rule:
Atoms, except Hydrogen and Helium, are most stable with eight electrons in their valence shell.
This principle states that atoms will gain, lose, or share electrons to achieve a full valence shell.
Chemical Formula Examples:
Oxygen (6 valence electrons) commonly interacts with 2 Hydrogen atoms, forming H₂O (water).
In this example, oxygen achieves stability by gaining two electrons.
Carbon often forms four bonds with hydrogen atoms to attain full valence shell, creating methane (CH₄), a common carbon-containing compound.
Etymology of Hydrogen:
The name “hydrogen” reflects its role in forming water (from Greek hydro- for "water" and -gen for "maker").
Figure 2.7 - Electron Shells Visualization:
Illustrates how electrons orbit the atomic nucleus at distinct energy levels, highlighting example elements:
Hydrogen with half-filled shell, Helium fully filled, Carbon filling first shell and half-filling the second, Neon filling both shells.