Medical Physics & Electrotherapy IB Quiz

A pacemaker is an electronic device implanted in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate, maintaining an adequate heart rhythm to meet the body’s needs. It is essential for patients with arrhythmias, such as bradycardia or heart block, where the heart beats too slowly.

Sonography, or ultrasound imaging, uses high-frequency sound waves to create images of the inside of the body. It is particularly useful for examining soft tissues, which do not show up well on X-rays. Ultrasound is non-invasive and does not use ionizing radiation, making it safe for a variety of applications, including fetal imaging during pregnancy, and assessing organ structure and function. The ability to see live images helps in real-time diagnosis and treatments.

MRI, or Magnetic Resonance Imaging, utilizes the principles of nuclear magnetic resonance. In an MRI, the nuclei of hydrogen atoms in water molecules within the body are excited using a strong magnetic field and radio waves. When the nuclei return to their original state, they emit signals that are used to create detailed images of the body's internal structures. This technology is particularly adept at visualizing soft tissues and is invaluable in diagnosing a wide range of conditions.

PET stands for Positron Emission Tomography, a type of imaging test that allows physicians to check for diseases in the body. The scanner detects the radiation emitted by a positron-emitting radionuclide in the organ or tissue being examined. The images produced show where the radioactive substances are distributed in the body, helping doctors to see how well organs and tissues are functioning. PET scans are particularly useful for detecting cancer and examining effects of cancer treatment.

A defibrillator is primarily used to deliver a therapeutic dose of electric current to the heart when a patient is experiencing life-threatening arrhythmias, such as ventricular fibrillation or pulseless ventricular tachycardia. The electric shock delivered by the defibrillator depolarizes a large amount of the heart muscle, ending the arrhythmia. This allows the body's natural pacemaker to regain control and re-establish a normal heart rhythm.

Ionization in the context of medical physics refers to the process where ionizing radiation passes through air, causing the air molecules to lose electrons and form ions. This process is fundamental to the operation of various types of radiation detectors, which measure the concentration of ions to evaluate the presence and intensity of radiation. Understanding ionization is essential for ensuring radiation safety and effective application in medical imaging and treatments.

The Gray (Gy) is a unit of ionizing radiation dose in the International System of Units, used to measure the absorbed dose of radiation energy per unit mass of tissue. It is crucial in various applications, including radiotherapy, where it helps ensure that precise doses are administered to cancer patients. By measuring the energy absorbed, healthcare providers can better protect healthy tissue while maximizing the treatment impact on diseased tissues.

CT scans often require the use of a contrast agent, which is swallowed or injected into the patient’s bloodstream. The contrast agent helps to clearly define the organs and tissues being examined by making them appear different on the scan because it absorbs X-rays at a different rate than the surrounding tissues. This distinction helps in providing more detailed and accurate images, which are essential for diagnosis and treatment planning.

An impedance meter measures the resistance of tissues to the flow of electrical current in electrotherapy. It is crucial because different tissues and conditions exhibit specific impedance characteristics, which affect how the treatment should be applied. Accurate impedance measurements help in customizing electrotherapy settings to optimize therapeutic outcomes, ensuring that the right amount of energy is delivered to the targeted area without causing discomfort or harm to the patient.

A Linear Accelerator (LINAC) is used in external beam radiotherapy to treat cancer. It generates high-energy electrons that are targeted to conform to the shape of a patient's tumor. The accuracy and intensity of the beam can be controlled so that it destroys cancer cells while sparing surrounding healthy tissue. LINACs are pivotal in modern oncology because they offer precise treatment options with fewer side effects compared to traditional radiation therapy methods.