DP Physics Questionbank

Description

Nature of science:

Risk analysis: The doctor’s role is to minimize patient risk in medical diagnosis and procedures based on an assessment of the overall benefit to the patient. Arguments involving probability are used in considering the attenuation of radiation transmitted through the body. (4.8)

Understandings:

• Detection and recording of X-ray images in medical contexts
• Generation and detection of ultrasound in medical contexts
• Medical imaging techniques (magnetic resonance imaging) involving nuclear magnetic resonance (NMR)

Applications and skills:

• Explaining features of X-ray imaging, including attenuation coefficient, half-value thickness, linear/mass absorption coefficients and techniques for improvements of sharpness and contrast
• Solving X-ray attenuation problems
• Solving problems involving ultrasound acoustic impedance, speed of ultrasound through tissue and air and relative intensity levels
• Explaining features of medical ultrasound techniques, including choice of frequency, use of gel and the difference between A and B scans
• Explaining the use of gradient fields in NMR
• Explaining the origin of the relaxation of proton spin and consequent emission of signal in NMR
• Discussing the advantages and disadvantages of ultrasound and NMR scanning methods, including a simple assessment of risk in these medical procedures

Guidance:

• Students will be expected to compute final beam intensity after passage through multiple layers of tissue. Only parallel plane interfaces will be treated.

Data booklet reference:

International-mindedness:

• There is constant dialogue between research clinicians in different countries to communicate new methods and treatments for the good of patients everywhere
• Organizations such as Médecins Sans Frontières provide valuable medical skills in parts of the world where medical help is required

Theory of knowledge:

• “It’s not what you look at that matters, it’s what you see.” – Henry David Thoreau. To what extent do you agree with this comment on the impact of factors such as expectation on perception?

Utilization:

• Scanning the human brain (see Biology sub-topic A.4)

Aims:

• Aim 4: there are many opportunities for students to analyse and evaluate scientific information
• Aim 8: the social impact of these scientific techniques for the benefit of humankind cannot be over-emphasized
• Aim 10: medicine and physics meet in the hi-tech world of scanning and treatment. Modern doctors rely on technology that arises from developments in the physical sciences.

Directly related questions

• 18M.3.HL.TZ2.15b.iii: Compare the use of high and low energy X-rays for medical imaging.
• 18M.3.HL.TZ2.15b.ii: A monochromatic X-ray beam of energy 20 keV and intensity I0 penetrates 5.00 cm of fat and then...
• 18M.3.HL.TZ2.15b.i: State what is meant by half-value thickness in X-ray imaging.
• 18M.3.HL.TZ2.15a: Outline the formation of a B scan in medical ultrasound imaging.
• 18M.3.HL.TZ1.14d.ii: Explain, with appropriate calculations, why a gel is used between the transducer and the skin.
• 18M.3.HL.TZ1.14d.i: Calculate the density of skin.
• 18M.3.HL.TZ1.14c: Suggest one reason why doctors use ultrasound rather than X-rays to monitor the development of a...
• 18M.3.HL.TZ1.14b: Describe one advantage and one disadvantage of using high frequencies ultrasound over low...
• 18M.3.HL.TZ1.14a: Outline how ultrasound is generated for medical imaging.
• 17N.3.HL.TZ0.16b: A technician operates an X-ray machine that takes 100 images each day. Estimate the width of the...
• 17N.3.HL.TZ0.16a: Show that the attenuation coefficient of lead is 60 cm–1.
• 17M.3.HL.TZ2.16: In nuclear magnetic resonance (NMR) imaging radio frequency electromagnetic radiation is detected...
• 17M.3.HL.TZ2.15c.ii: Ultrasound of intensity 0.012 W\(\,\)cm–2 is incident on a water–muscle boundary. The acoustic...
• 17M.3.HL.TZ2.15c.i: Calculate the acoustic impedance Z of muscle.
• 17M.3.HL.TZ2.15b: Describe how an ultrasound transducer produces ultrasound.
• 17M.3.HL.TZ2.15a: State a typical frequency used in medical ultrasound imaging.
• 17M.3.HL.TZ1.13c.iii: the non-uniform magnetic field applied to the patient.
• 17M.3.HL.TZ1.13c.ii: the radio-frequency signal emitted towards the patient.
• 17M.3.HL.TZ1.13c.i: the large uniform magnetic field applied to the patient.
• 17M.3.HL.TZ1.13b: The diagram shows X-rays incident on tissue and bone. The thicknesses of bone and tissue are...
• 17M.3.HL.TZ1.13a: Outline why the fracture in a broken bone can be seen in a medical X-ray image.
• 16N.3.HL.TZ0.20b: Explain how a gradient field and resonance are produced in NMR to allow for the formation of...
• 16N.3.HL.TZ0.20a: State the property of protons used in nuclear magnetic resonance (NMR) imaging.
• 16N.3.HL.TZ0.19c: Suggest why more energetic beams of about 150 keV would be unsuitable for imaging a bone–muscle...
• 16N.3.HL.TZ0.19b: The density of muscle is 1200 kg m–3. Calculate the ratio of intensities to compare, for a beam...
• 16N.3.HL.TZ0.19a: Show that the attenuation coefficient for bone of density 1800 kg m–3, for X-rays of 20 keV, is...
• 16M.3.HL.TZ0.16b: Explain why a gradient field is required in nuclear magnetic resonance (NMR) imaging.
• 16M.3.HL.TZ0.16a: State one advantage and one disadvantage of magnetic resonance imaging (MRI) compared to X-ray...
• 16M.3.HL.TZ0.15b: With reference to your answers to (a)(i) and (a)(ii), discuss the advantages of using the...
• 16M.3.HL.TZ0.15a: X-rays are incident on an aluminium sheet of thickness 8.0 cm. Calculate the fraction of the...
• 15M.3.HL.TZ1.19a: Outline how ultrasound is generated for medical diagnostic purposes.
• 15M.3.HL.TZ1.20a: Two parallel beams of monochromatic X-rays of the same intensity are incident on equal...
• 15M.3.HL.TZ1.19b: When ultrasound of intensity I0 travels in a medium of acoustic impedance Z1 and is incident on a...
• 15M.3.HL.TZ1.19c: In medical scanning, practitioners have the option of using A-scans or B-scans. Distinguish, with...
• 15M.3.HL.TZ1.20b: Explain how fluorescent emitters are used to enhance the image formed on a photographic X-ray plate.
• 15M.3.HL.TZ2.21b: The acoustic impedances for various media are shown in the table. Ultrasound is incident...
• 15M.3.HL.TZ2.21a: Define acoustic impedance of a medium.
• 15M.3.HL.TZ2.20a: (i) X-rays travelling in a medium experience attenuation. State what is meant by...
• 15N.3.HL.TZ0.18b: Medical practitioners select the frequency of the ultrasound depending on the diagnosis they are...
• 15N.3.HL.TZ0.18a.ii: State the significance of acoustic impedance in the use of ultrasound techniques.
• 15N.3.HL.TZ0.18a.i: Define acoustic impedance.
• 14M.3.HL.TZ1.21b: The graph below shows the variation of attenuation coefficient μ with photon energy E for X-rays...
• 14M.3.HL.TZ1.21a: Define attenuation coefficient.
• 14N.3.HL.TZ0.22b.ii: Suggest why an X-ray scan does not allow for the differentiation between muscle and blood.
• 14N.3.HL.TZ0.22c: A contrast medium containing iodine is injected into the patient. This increases the attenuation...
• 14N.3.HL.TZ0.22d: X-rays are a form of ionizing radiation. To reduce the danger to a patient, the intensity of...
• 14N.3.HL.TZ0.22a.i: Define attenuation coefficient.
• 14N.3.HL.TZ0.22b.i: Calculate the ratio \(\frac{{{I_{{\text{blood}}}}}}{{{I_{{\text{muscle}}}}}}\) for 1 cm of tissue.
• 14N.3.HL.TZ0.22a.ii: Calculate the half-value thickness for blood.
• 14M.3.HL.TZ2.19c: The intensity of a parallel X-ray beam is reduced to 50% of its initial intensity when it passes...
• 14M.3.HL.TZ2.20c: State one advantage and one disadvantage of using ultrasound of frequency 1 MHz, rather than 3...
• 14M.3.HL.TZ2.20a: Define acoustic impedance
• 14M.3.HL.TZ2.20b: (i)     Calculate the speed of ultrasound in muscle. (ii)     Determine the thickness of the...
• 13M.3.HL.TZ1.21a: The diagram below shows X-rays being used to scan a sample of bone and muscle. (i) Outline how...
• 13M.3.HL.TZ1.21b: The same sample is now investigated with an ultrasound A-scan from the side as shown. (i)...
• 13M.3.HL.TZ2.21a: Define attenuation coefficient.
• 13M.3.HL.TZ2.21b: The graph shows how the attenuation coefficient μ of muscle varies with photon energy E.   In...
• 13M.3.HL.TZ2.22b: State two advantages of NMR imaging over computed tomography (CT) imaging.   1.   2.
• 13M.3.HL.TZ2.22a: Outline the physical principles of NMR imaging.
• 12M.3.HL.TZ1.15b: The table gives the velocity of sound in, and the densities of, the materials. (i) State the...
• 11M.3.HL.TZ2.19a: Use the data from the table to calculate a value for the density of bone.
• 11M.3.HL.TZ2.19b: The fraction F of the intensity of an ultrasound wave reflected at the boundary between two media...
• 11M.3.HL.TZ2.19c: Use your answers in (b) to explain the need for a gel on the patient’s skin.
• 11N.3.HL.TZ0.16a: Outline how ultrasound is produced for use in diagnostic imaging.
• 11N.3.HL.TZ0.16b: In order to look for damage to the chambers of the heart, ultrasound is used to form an image of...
• 11N.3.HL.TZ0.16c: The speed of sound in skin is about five times the speed of sound in air. Given that the density...
• 11N.3.HL.TZ0.16d: Explain, using your answer to (c), why, in using ultrasound for imaging, a layer of gel is placed...
• 11N.3.HL.TZ0.16e: A wide range of frequencies of ultrasound may be used to image internal body organs. The choice...
• 12N.3.HL.TZ0.20d: Outline why X-rays are not suitable to image an organ such as the liver.
• 12N.3.HL.TZ0.20a: Define the attenuation coefficient as applied to a beam of X-rays travelling through a medium.
• 12N.3.HL.TZ0.20b: Derive the relationship between the attenuation coefficient μ and the half-value thickness...
• 13N.3.HL.TZ0.16a: Define attenuation coefficient.
• 13N.3.HL.TZ0.16c: A complete dental record of all the teeth in a patient’s mouth requires about 20 separate X-ray...
• 13N.3.HL.TZ0.16d: The table shows data about the acoustic impedance of some materials that would be involved in the...
• 12M.3.HL.TZ2.20a: The half-value thickness of the tissue is 4.0 cm. On the axes below, sketch a graph to show the...
• 12M.3.HL.TZ2.20b: Calculate the attenuation coefficient of X-rays for this tissue.
• 12M.3.HL.TZ2.19: This question is about nuclear magnetic resonance (NMR). In nuclear magnetic resonance imaging,...
• 12M.3.HL.TZ2.20c: For a different type of tissue, the ratio \(\frac{{{I_t}}}{{{I_0}}}\) is smaller for the same...
• 12M.3.HL.TZ2.20d: Barium has an attenuation coefficient that is much larger than that for human tissue. Explain...
• 11M.3.HL.TZ1.21b: A successful ultrasound scan relies on changes of acoustic impedance around the structure being...
• 11M.3.HL.TZ1.21a: When producing the X-ray photograph, the dose is kept to a minimum by a technique called...
• 10N.3.HL.TZ0.I2c: For X-rays of higher energy than those in (b), the half-value thickness is greater than 3.50 mm....
• 10N.3.HL.TZ0.I2a: Define half-value thickness.
• 10N.3.HL.TZ0.I2b: The half-value thickness in tissue for X-rays of a specific energy is 3.50 mm. Determine the...