Book contents
- Frontmatter
- Contents
- List of contributors
- Foreword by Professor Lord Ara Darzi KBE
- Preface
- Section 1 Perioperative care
- Section 2 Surgical emergencies
- Section 3 Surgical disease
- Section 4 Surgical oncology
- Section 5 Practical procedures, investigations and operations
- Section 6 Radiology
- Principles and safety of radiology
- X-rays
- Contrast examinations
- Ultrasound
- Computed tomography (CT)
- Magnetic resonance imaging (MRI)
- Section 7 Clinical examination
- Appendices
- Index
X-rays
Published online by Cambridge University Press: 06 July 2010
- Frontmatter
- Contents
- List of contributors
- Foreword by Professor Lord Ara Darzi KBE
- Preface
- Section 1 Perioperative care
- Section 2 Surgical emergencies
- Section 3 Surgical disease
- Section 4 Surgical oncology
- Section 5 Practical procedures, investigations and operations
- Section 6 Radiology
- Principles and safety of radiology
- X-rays
- Contrast examinations
- Ultrasound
- Computed tomography (CT)
- Magnetic resonance imaging (MRI)
- Section 7 Clinical examination
- Appendices
- Index
Summary
Introduction
X-rays are transmitted through different parts of the body with varying intensity. The number of X-rays that are transmitted through a material depends on the atomic number and the density of that material. For example, bone has a higher atomic number and a greater density than air; fewer X-rays penetrate bone than the air-filled lungs. The plain radiograph is obtained when the emergent X-rays interact with a photosensitive plate.
Gas, fat, soft tissue/fluid, bone/calcification and non-organic radio-opaque materials/contrast can be differentiated on a plain radiograph.
Indications
‘Making the Best Use of a Department of Clinical Radiology: Guidelines for Doctors’ is a very useful reference. If in doubt, discuss the case with a radiologist.
Preoperative chest X-ray: not routinely performed. Consider if the patient is known to have cardiorespiratory disease, >60 years.
Preoperative cervical spine: not routinely performed. Consider in patients who are at risk of atlanto-axial instability, who may be at risk of subluxation at the time of intubation e.g. rheumatoid arthritis, Down's syndrome.
Post-procedure chest X-ray: to check the satisfactory position of tubes and lines:
▪ Nasogastric tube: tip should be seen within the stomach i.e. below the diaphragm; this should be confirmed before use.
▪ Endotracheal tube (ETT): flexion and extension of the neck can cause the tip of ETT to move by up to 5 cm; therefore the tip should be placed 5 cm above the carina. If seen within 2 cm of the carina then the likelihood of it passing into the right main bronchus is increased and the tube should be withdrawn.
▪ Tracheostomy tube: the tip should be seen centrally within the trachea at the level of T3.
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- Type
- Chapter
- Information
- Hospital SurgeryFoundations in Surgical Practice, pp. 706 - 711Publisher: Cambridge University PressPrint publication year: 2009