This document discusses x-rays and medical imaging technology. It covers: 1. X-rays are a form of ionizing radiation that can potentially damage DNA and increase cancer risk, though risk from medical imaging is generally small depending on dose, age, sex, and body region exposed. 2. X-rays are used in medical imaging to non-invasively diagnose disease, monitor therapy, and guide procedures through techniques like radiography, fluoroscopy, and CT scans. 3. Principles of radiation protection include justifying exams based on medical need and optimizing techniques to use the lowest dose for adequate diagnosis. Risks include potential long-term cancer risk and rare tissue effects.

1. Technology basis of roentgen
diagnostics.
Organization of job and
equipment.

2. Ionizing radiation
is a form of radiation that has enough energy to
potentially cause damage to DNA and may
elevate a person’s lifetime risk of developing
cancer.

3. The risk of developing cancer from medical
imaging radiation exposure is generally very
small, and it depends on:
• Radiation dose - The lifetime risk of cancer increases the larger the
dose and the more X-ray exams a patient undergoes.
• Patient’s age - The lifetime risk of cancer is larger for a patient who
receives X-rays at a younger age than for one who receives them at
an older age (hormonal status and metabolism)
• Patient’s sex - Women are at a somewhat higher lifetime risk than
men for developing radiation-associated cancer after receiving
the same exposures at the same ages.
• Body region - Some organs are more radiosensitive than others.

4. Benefits of X-ray examinations
`The discovery of X-rays represented major advances
in medicine.
X-ray imaging exams are recognized as a valuable
medical tool for a wide variety of examinations and
procedures. They are used to:
• noninvasively and painlessly help to diagnosis
disease and monitor therapy;
• support medical and surgical treatment planning;
and
• guide medical personnel as they insert catheters,
stents, or other devices inside the body, treat
tumors, or remove blood clots or other blockages.

5. Risks
• a small increase in the possibility that a person
exposed to X-rays will develop cancer later in life.
• tissue effects such as cataracts, skin reddening, and
hair loss, which occur at relatively high levels of
radiation exposure and are rare for many types of
imaging exams.
• The exact dose distribution and time !
• another risk of X-ray imaging is possible reactions
associated with an intravenously injected contrast
agent (dye), that is sometimes used to improve
visualization.

6. Principles of radiation protection:
Justification
• The imaging procedure should be judged to do more
good (e.g., diagnostic efficacy of the images) than
harm (e.g., detriment associated with radiation
induced cancer or tissue effects) to the individual
patient.
• Therefore, all examinations using ionizing radiation
should be performed only when necessary to answer
a medical question, treat a disease, or guide
procedure (intervention).
• The clinical indication and patient medical history
should be carefully considered before referring a
patient for any X-ray examination.

7. Principles of radiation protection:
Optimization
• X-ray examinations should use techniques that are
adjusted to administer the lowest radiation dose
that yields an image quality adequate for diagnosis
or intervention (i.e., radiation doses should be "As
Low as Reasonably Achievable" (ALARA)).
• The technique factors used should be chosen based
on the clinical indication, patient size, and
anatomical area scanned; and the equipment should
be properly maintained and tested.

8. Radiology and children
• children have an increased
radiosensitivity to ionizing
radiation (on average 2 - 3
times), which creates high risk,
both somatic and genetic
effects of radiation;
• physical and physiological
differences between adults and
children, including the
closeness of the bodies, as well
as irregular dynamics of their
development, lead to higher
levels of radiation children
than adults...

9. methods of limiting and reducing
radiation exposure in children
• !!!!!!! exclude unnecessary studies or those studies
in which there is no need... !!!!!
• Not subject to preventive radiological studies
children up to 14 years of age and pregnant women.
• Routine radiographs of the thorax should not be
performed simply because the baby is unhealthy.
Before making the patient images, it is necessary to
verify the presence of obvious clinical
manifestations

10. Caution- to avoid danger
Women of child-bearing age should be
questioned about possibility of pregnancy
before abdominal X-ray investigation

11. Imaging for medical purposes
Involves a team which includes the service of
• radiologists,
• radiographers (X-ray technologists),
• sonographers (ultrasound technologists),
• medical physicists,
• nurses,
• biomedical engineers, and
• other support staff working together to optimize the
wellbeing of patients, one at a time.
Appropriate use of medical imaging requires a
multidisciplinary approach.

12. The primary role of a radiologic
technologist
 is using x-ray equipment to produce images of
tissues, organs, bones, and vessels and
administering radiation therapy treatments.
 also called an x-ray technologist or radiographer

13. Homework survey
1. History of the discovery of X-rays
2. The physical properties of X-rays
3. Imaging mechanism (X-ray tube)

14. X-ray – as ionizing radiation

15. What are x-rays?
 No mass
 No charge
 Energy
X-rays are a type
of electromagnetic
energy

27. The principles of radiography

28. X-ray modalities
General method Complementary methods Contrast media
Radiography Convential linear tomography Barium meal
Fluoroscopy Decubitus Barium enema
Fluorography Cholangiography
Mammography Angiography
CT-scan Bronchography ….

29. All X-ray modalities work on the same
basic principle:
• an X-ray beam is passed through the body where
a portion of the X-rays are either absorbed or
scattered by the internal structures, and the
remaining X-ray pattern is transmitted to a
detector (e.g., film or a computer screen) for
recording or further processing by a computer.

30. X ray exams differ in their purpose:
• Radiography - a single image is recorded for later evaluation.
Mammography is a special type of radiography to image the internal
structures of breasts.
• Fluoroscopy - a continuous X-ray image is displayed on a monitor,
allowing for real-time monitoring of a procedure or passage of a
contrast agent (“dye”) through the body. Fluoroscopy can result in
relatively high radiation doses, especially for complex interventional
procedures (such as placing stents or other devices inside the body)
which require fluoroscopy be administered for a long period of time.
• CT-scan - many X-ray images are recorded as the detector moves
around the patient's body. A computer reconstructs all the
individual images into cross-sectional images or “slices” of internal
organs and tissues. A CT exam involves a higher radiation dose than
conventional radiography because the CT image is reconstructed
from many individual X-ray projections.

31. How image is produced

33. X ray film

34. Radiographic film

38. How do x-rays passing through the
body create an image?
• X-rays that pass through the body represent the
image dark (black)
• X-rays that are totally absorbed represent image
ligth (white)
__________________________________
• Air - image is dark (black)
• Metal = image is light (white)

43. Principles of radiography

44. Radiography
• Different views of the chest
can be obtained by changing
the relative orientation of the
body and the direction of the
x -ray beams:
• The most common views are:
1. Posteroanterior view (PA);
2. Anteroposterior view (AP);
3. Lateral

45. Radiography PA view

46. Lateral
film

49. Basic Concepts
• One view is no view – use it all!
• Patterns are your clue
• Be sure you are looking
• Know what you’re looking for
• Know the limits of your test

50. One View is No View Posterior sulcus nodule = Cancer

51. One View is No View
RML collapse

52. Patterns are Your Clue
Interstitial Lung Disease - Acute
PCP Pneumonia
CHF

53. Patterns are Your Clue

54. Find the pathology
What clues do you have?

55. Can you recognize
shapes and density?

56. Find the pathology
What clues do you have?

57. History: 11 year old twisting
injury of the foot

58. Word bank: epiphysis, metaphysis, diaphysis, cortex, medullary cavity
Naming the parts of a long bone

59. Review: What are the 5 basic radiographic
densities from black to bright white?
• Air
• Fat
• Soft tissue/fluid
• Bone/mineral
• Metal

60. Practice: How do x-rays create an image of
internal body structures?
• X-rays pass through the body to varying degrees
• Higher atomic number structures block x-rays
better, example bone
• Lower atomic number structures allow x-rays to
pass through, example: air in the lungs

64. Real time
imaging