Cancer and Body Organization

• Doctors utilize radioactive decay to transform atoms and diagnose/treat illness.

Levels of Organization

• Cell: The fundamental unit of life.
• Tissue: A group of similar cells performing a specific function.
• Organ: A collection of tissues completing a specialized bodily function (e.g., lungs, skin).
• Organ System: A group of organs collaborating on a specific function (e.g., digestive, reproductive).
• Organism: A living entity (e.g., human, mouse).

Cancer

• Cancer arises from uncontrolled growth and division of abnormal cells due to genetic mutations that disrupt cell regulation.
• Tumors are abnormal cell growths.
• Benign tumors are non-cancerous.
• Malignant tumors are cancerous, invade nearby tissues/organs and spread (metastasize).
• Cancer causes include:
  • Environmental factors: radiation, chemicals and pollution
  • Lifestyle factors: poor diet, smoking, lack of exercise and alcohol consumption.
  • Inherited factors: passed down genetic predispositions
  • Biological factors: viruses, chronic inflammation.
• Breast cancer is the most common cancer in women.
• Prostate and Lung cancer are the most common cancer in men.
• Colon cancer is also common.
• Cancer treatments:
• Surgery: physically removes cancerous masses
• Chemotherapy: to kill cancer cells with chemicals
  • Radiation therapy: is a unit focus and uses energy to destroy cancer cells' DNA, so they can no longer divide
  • Radiation therapy involves high-energy rays.
  • Radiation therapy can also pose health risks.

Atomic Structure and Ions

• An atom diagram shows three subatomic particles.
  • Protons, neutrons, and electrons are distinguishable.
  • The periodic table is used to determine a number of protons, neutrons, and electrons in an element.
  • Ions are atoms that have either gained or lost electrons, and differ from atoms.
• Atoms are matter's basic units.
  • Approximately 100 trillion atoms are in each cell.
  • Electrically neutral atoms have equal protons (positive charge) and electrons (negative charge).
  • Neon (Ne) exemplifies a neutral atom.
• Nucleus: The atom's center, containing protons and neutrons.
• Subatomic particles comprise:
  • Protons: positive charge
  • Particles: found in the nucleus
  • Neutrons: Particles with no charge are located in the nucleus.
  • Electrons: negatively charged particles in an atom.
  • The number of protons = the number of electrons in the atom
• Ions are atoms or molecules with gained or lost electrons, giving them an electric charge.
  • Losing electrons results in a positive charge like Na+ (sodium cation).
  • Gaining electrons results in a negative charge like Cl- (chloride anion).

Periodic Table

• The periodic table presents elements with their atomic number, symbol, and average atomic mass; elements are grouped by similar chemical properties.
• Mass number: the total of protons and neutrons in an atom's nucleus.
• Atomic number: the number of protons in an atom's nucleus.

Isotopes and Radiation

• Isotopes: explained as atoms of the same element, possessing equal protons, but different neutrons.
• Unstable isotopes decay into new elements while releasing radiation.
• Electromagnetic radiation can be used to excite electrons.
• Ionizing radiation transfers energy to knock electrons out of atoms, ionizing them.
• Isotopes are atoms of the same element with the same number of protons but differing numbers of neutrons.
• Calculating the average atomic mass of an element given percentages of the isotopes is possible.
• Average Atomic Mass: it is calculated as the weighted average from the atomic masses for the isotopes of an element and is based on the weight and abundance of its isotopes.
• Stable isotopes have a balanced ratio of protons and neutrons, and they do not change over time like Lithium-7 (Li).
• Unstable isotopes have an unbalanced ratio of protons and neutrons, and they undergo radioactive decay, causing them to emit radiation.
• Radioactive decay is the loss of energy by the unstable atomic nucleus which emits radiation and transforms elements in the process.
• Nuclear radiation is the energy and particles released during radioactive decay (alpha, beta and gamma). Can penetrate materials.

Properties of Radiation

• Nuclear radiation has three types.
• Ionizing ability and penetrating properties are able to be explained for the three types of ionizing radiation.
• Nuclear decay equations should be written for all three types of ionizing radiation.
• Alpha (α) decay features:
  • High-energy Helium
  • Made of 2 neutrons and 2 protons and is equal to 4 atomic mass and a +2 charge
  • When the atom loses an He particle, the atomic mass # decreases by 4 and the charge by 2
  • A new element is created as a result and is 2 places lower on the periodic table.
• Beta (β) Decay:
  • When an isotope has too many neutrons. -A neutron changes to a proton and an electron
  • The electron has high energy and is called a b particle.
  • A new element is formed that is one place higher in the periodic table.
• Gamma (γ) Decay:
  • Gamma rays are high-energy forms of light.
  • To get rid of excess energy, a gamma wave is emitted.
• Alpha particles are mostly damaging because they are a heavier mass and higher charge.

Radiation application

• Half-life: the time required for a radioactive isotope to decay to half of its initial quantity, happens at a constant rate.
• Activity: the average number of decays per second measured in Becquerel (Bq).
• The number of radioactive particles decreases exponentially.
• Basics involve using the properties of nuclear radiation to scan for and treat cancers.
  • A specific application of Nuclear medicine should be explained.
• Medical Application:
  • Therapeutic applications includes; external and internal therapy
    • external therapy is done through targeting cancerous tumors from outside via things like gamma knives.
    • internal therapy is done through putting small pieces of radioactive material inside the tumor or right next to it via radiation seeds.
  • Diagnosis: can use radiation to penetrate through the body to see the inside of the body without surgery via PET Scans, X-rays, MRIs, etc.
  • In order to achieve this, a radioactive tracer is injected, swallowed, or inhaled by the patient and absorbed in specific tissues or organs.
• High-energy radioactive isotopes emit ionizing radiation and damage is the cell's DNA.
• Damage prevents the cell from dividing and will then cause the cells to die.
• Some types of radiation like gamma rays can penetrate deep into the body for tumors in the brain or lungs.
• Isotopes for appropriate half-lives can be chosen to treat tumors that decay quickly and minimize harm to the patient.
• Radioactive isotopes can be combined with safe chemicals can be absorbed more by cancer cells than normal cells.
• Radiation therapy maximises the effect on the cancer, while not effecting tissues around it.