Non-Invasive therapy Notes GPT Flashcards
(80 cards)
What major global trend in healthcare spending drives interest in non-invasive therapies?
Rising healthcare costs as a growing fraction of GDP worldwide.
Why is an ageing population particularly relevant for non-invasive therapies?
Older patients often have multiple or systemic conditions, making invasive surgery riskier and less scalable.
Which diseases have become predominant as a result of vaccination and better infection control?
Non-communicable (chronic) diseases such as cancer, heart disease, and diabetes.
Why can systemic or metastatic disease be poorly addressed by surgery alone?
Surgery is local; metastases often spread throughout the body and require whole-body (systemic) treatments.
Give one main advantage of non-invasive therapies over invasive methods.
Reduced trauma to healthy tissues, often leading to faster recovery times.
Name two non-invasive modalities covered in this course.
(1) Radiation therapy (ionizing or non-ionizing), (2) Ultrasound-based therapy, (3) Drug-based approaches, etc.
What defines ionizing radiation in terms of photon energy? (threshold)
Ionizing radiation has photon energies above about 10 eV, sufficient to knock electrons off atoms.
State the equation linking photon energy (E) to frequency (f).
E=hf, where h is Planck’s constant.
How are X-rays typically generated for radiotherapy?
By accelerating electrons in a linear accelerator (LINAC) and colliding them with a metal target.
How do gamma rays differ from X-rays in their source?
Gamma rays arise from radioactive decay in nuclei; X-rays typically come from electronic transitions or bremsstrahlung in an X-ray tube.
What are alpha particles composed of, and how deeply do they penetrate tissue?
Alpha particles are helium nuclei (2 protons + 2 neutrons); they have very poor penetration (a few cell layers).
In what scenario is alpha-particle therapy often used?
As alpha-emitting radiopharmaceuticals for metastatic bone lesions or targeted alpha therapies.
Why do protons deposit most of their energy at the Bragg peak?
Because protons slow down rapidly near the end of their path in tissue, releasing maximal energy there.
Which formula is used to calculate absorbed dose (D)?
D=E/m (energy deposited per unit mass).
What is the half-value layer (HVL) in radiation physics?
The thickness of an absorber that reduces the beam intensity by 50%.
Name the key biological molecule targeted by ionizing radiation.
DNA. Radiation-induced double-strand breaks can trigger cell death.
Why is fractionation used in radiation therapy?
It allows normal cells to repair damage while tumor cells, often less proficient at repair, accumulate lethal damage.
What is the main advantage of proton therapy over conventional X-rays?
Protons spare healthy tissue beyond the tumor due to the sharp dose falloff after the Bragg peak.
How do beta particles differ from alpha particles?
Beta particles are high-speed electrons (or positrons), with deeper penetration than alpha particles but shallower than photons.
Give an example of a radiopharmaceutical for beta therapy.
Iodine-131 for thyroid cancer, or beta-emitting isotopes linked to antibodies in radio-immunotherapy.
How does oxygenation influence radiotherapy efficacy?
Oxygen enhances the formation of free radicals, increasing radiation-induced DNA damage in tumor cells.
What is the typical energy range for medical LINAC X-ray beams?
Around 6–15 MeV.
Name two types of non-ionizing electromagnetic radiation used therapeutically.
Visible/Infrared light (lasers) and microwaves (RF waves).
How does laser light cause tissue heating or ablation?
Photons elevate electron energy levels in tissue molecules, converting photonic energy into heat.
