Radiation - Exposure and Protection MCQs

Ionizing radiation is the term given to forms of radiation that are energetic enough to displace orbiting electrons from the atoms in the absorbing medium, thus forming positive ions. High Energy Electromagnetic Radiation like X Rays, Gamma Rays, and Cosmic Rays are Ionising Radiation Particulate Radiation Like Alpha, Beta, Protons, Neutrons, and Electrons are Ionising Radiation. Most other electromagnetic radiation like UV rays, Visible light, Infrared Rays, Radiowaves are Nonionising Sound waves used in Ultrasound are also Nonionising. Reference: Bell, D. Ionizing radiation. Reference article, Radiopaedia.org. https://doi.org/10.53347/rID-59177

All electromagnetic Radiation have the same velocity, that is velocity of speed of Light. Reference: Christensen's Physics of diagnostic radiology page 6

The embryo/foetus is most susceptible to teratogenic effects of radiation during 2-7 weeks as this is the period of organogenesis The foetus is more resistant to the radiation during the second and third trimester. Reference : Yoon I, Slesinger TL. Radiation Exposure In Pregnancy. [Updated 2022 May 8]. In: Stat Pearls [Internet]. Treasure Island (FL): Stat Pearls Publishing; 2022 Jan.

Accidental Exposure of Radiation during pregnancy-reassure the patient and continue the pregnancy as the threshold required for fetal damage is very high and termination is usually not advised unless very high exposure Above 10RAD, which is highly unlikely with routine diagnostic modalities.

Modern X ray tube has a rotatory anode, not cathode Motor is attached to the anode to make it rotatory The Cathode is made of Tungsten alloyed with Thorium The Target of Anode is made of Tungsten Alloyed with Rhenium The major source of X RAY Generation in Modern X ray tube is Bremstrahlung Radiation/Braking Radiation

According to Inverse square law in radiation, the intensity of radiation is inversely proportional to the square of distance from the source. Rapidly dividing cells , which are less differentiated are actually more radiosensitive Amongst the body cells, the most sensitive are spermatogonia and the least sensitive are nerve cells and muscle fibres Gi mucosa is Radiosensitive Small blood vessels are generally radioresistant

The most commonly used thickness of Lead in Lead Apron for Radiation protection -0.5mm The Minimum Thickness of Lead in Lead Apron required for radaiation protection -0.25mm

Ultrasound does not use ionising radiation and is considered safe for use at all gestational ages in pregnancy. Reference: A Radiologist's Guide to the Performance and Interpretation of Obstetric Doppler US, Anne M. Kennedy and Paula J. Woodward, RadioGraphics 2019 39:3, 893-910