Radio imaging examinations are noninvasive tests that produce images of inside patient's body and provide valuable information to help diagnosis of illnesses and injuries.
The ray of hope for radiological investigation has first appeared on November 8, 1895, when physicist Professor Conrad Wilhelm RÖntgen (1845–1923) stumbled on X-rays while experimenting with Lenard tubes and Crookes tubes and began studying them. He wrote an initial report “ON A NEW KIND OF RAY: A PRELIMINARY COMMUNICATION” and on December 28, 1895 submitted it to Würzburg's Physical-Medical Society journal. This was the first paper written on X-rays. Röntgen referred to the radiation as “X”, to indicate that it was an unknown type of radiation. The name stuck, although (over Röntgen's great objections) many of his colleagues suggested calling them Röntgen rays. They are still referred to as such in many languages, including German, Hungarian, Danish, Polish, Swedish, Finnish, Estonian, Russian, Japanese, Dutch, Georgian, Hebrew, and Norwegian. Röntgen received the first Nobel Prize in Physics for his discovery.
X-rays are electromagnetic energy waves that act similarly to light rays, but at wave lengths approximately 1,000 times shorter than those of light. Röntgen holed up in his laboratory and conducted a series of experiments to better understand his discovery. He learned that X-rays penetrate human flesh but not higher-density substances such as bone or lead and that they can be photographed. He discovered their medical use when he made a picture of his wife's hand on a photographic plate formed due to X-rays. The photograph of his wife's hand was the first photograph of a human body part using X-rays. When she saw the picture, she said “I have seen my death”. Röntgen immediately noticed X-rays could have medical applications. Along with his 28 December Physical-Medical Society submission he sent a letter to physicians he knew around Europe (January 1, 1896). The first use of X-rays under clinical conditions was by John Hall-Edwards in Birmingham, England on 11 January 1896, when he radiographed a needle stuck in the hand of an associate. On February 14, 1896 Hall-Edwards was also the first to use X-rays in a surgical operation.
Röntgen's discovery was labeled as medical miracle and X-rays soon became an important diagnostic tool in medicine, allowing doctors to see inside the human body for the first time without surgery. In 1897, X-rays were first used on a military battlefield, during the Balkan War, to find bullets and broken bones inside patients.
What is X-ray?
- X-rays are a form of electromagnetic waves that can penetrate through the body and the images appear in shades of black and white, depending on the type of tissue the X-rays pass through.
- Bones absorb more radiation and appear white on X-rays.
- Muscle or fat absorbs less, and appears in shades of gray on X-ray film.
- Air absorbs little of the X-rays, so the lungs appear black on an X-ray film.
TYPES OF X-RAYS
Conventional Plain X-rays
The most common of X-rays and is the cheapest modality of radiological investigation.
Computed Tomography (CT) Scans
Computer-based three-dimensional X-ray images are processed to create detailed pictures (scans) of cross-sections of the body.
It is X-rays and a fluorescent screen to study moving or real-time structures in the body. When it is combined with swallowed or injected contrast agents the digestive processes or blood flow can be viewed. Clogged arteries can be opened by internally threaded contrast injected guided catheter using a fluoroscopy called cardiac angioplasty. Epidural injections or joint aspirations can be precisely done with the help of fluoroscopy.
WHAT ARE THE DANGERS AND RISKS OF X-RAYS?
When X-ray was first introduced, scientists were quick to realize the benefits of X-rays, but slower to comprehend the harmful effects of radiation. Initially, it was believed X-rays passed through flesh as harmlessly as light. However, within several years, researchers began to report cases of burns and skin damage after exposure to X-rays, and in 1904, Thomas Edison's assistant, Clarence Dally, who had worked extensively with X-rays, died of skin cancer. With the widespread experimentation with X-rays after their discovery in 1895 by scientists, physicians, and inventors came many stories of burns, hair loss, and worse in technical journals of the time. In February 1896, Professor John Daniel and Dr William Lofland Dudley of Vanderbilt University reported hair loss after Dr Dudley was X-rayed. A child who had been shot in the head was brought to the Vanderbilt laboratory in 1896. Daniel reported that 21 days after taking a picture of Dudley's skull (with an exposure time of 1 hour), he noticed a bald spot of 2 inches (5.1 cm) in diameter on the part of his head nearest the X-ray tube.
In August 1896 Dr HD Hawks, a graduate of Columbia College, suffered severe hand and chest burns from an X-ray demonstration. Elihu Thomson deliberately exposed a finger to an X-ray tube over a period of time and suffered pain, swelling, and blistering. Dally's death caused some scientists to begin taking the risks of radiation more seriously, but they still were not fully understood.
Though the risk of tissue damage due to X-ray radiation is relatively small, it may increase with cumulative repeated multiple X-ray exposure over one's life time. The risk of developing cancer, cataracts, and skin burns are likely to occur with cumulative exposure. Radiation does have some risks to consider, but it is also important to remember X-rays can help detect disease or injury at early stages so the ailment can be treated appropriately. Sometimes X-ray testing can be lifesaving.
BARIUM STUDIES FOR DIGESTIVE TRACT
Types of Barium X-rays
- Barium swallow
- Barium small bowel follow through
- Barium enema.
A barium swallow is to examine the back of the throat, esophagus, and stomach. With a barium swallow, the patient is asked to drink barium-containing chalky liquid. The indications for barium swallow include:
- Abdominal pain
- Unusual bloating
- Unexplained vomiting
- Weight loss of unexplained origin.
The barium coats the walls of the esophagus and stomach, which is then visible on X-rays. The test is effective in locating strictures, ulcers, hiatal hernias, erosions in the esophagus or stomach, muscle disorders such as achalasia, and other abnormalities such as esophageal cancer.
Barium Small Bowel Follow Through
Barium studies may also be used to look further down into the digestive tract. In a barium small bowel follow through the patient is observed as the barium passes beyond the stomach into the small intestine, and eventually makes its way to colon. In the procedure, the patient is often turned side to side to best visualize the small bowel or small intestine. A barium small bowel follow through may be done to help diagnose tumors of the small bowel, a small bowel obstruction, or inflammatory diseases of the small intestine such as Crohn's disease.
- Pain abdomen
- Rectal bleeding
- Unexplained vomiting
- Abnormal bowel movements
- Chronic diarrhea or constipation
- Unexplained weight loss
- Unusual bloating
- To locate anatomical abnormalities.
It is modality of choice for detecting pathology of large bowel and ano rectal region. It is mainly used for Hirschsprung disease to detect length of aganglionic segment. Before the availability of ultrasound scanning it was modality to diagnose and treat large bowel (Colo-colic) intussusception. Pre-procedure bowel preparation is not required
- Anterior: Toward the front of the body
- Posterior: Toward the back of the body
- Superior: Toward the top of the body
- Inferior: Toward the bottom of the body
- Medial: Toward the midline
- Lateral: Away from the midline.
- Erect: Standing or sitting
- Decubitus: Lying down
- Supine: Lying on back
- Prone: Lying face-down
- Lateral decubitus: Lying on one side
- Right lateral: Right side touches the cassette
- Left lateral: Left side touches the cassette.
Views in Chest Radiography
- Posteroanterior (PA)
- Anteroposterior (AP) erect
- Cross table lateral.
The chest radiograph is the most commonly requested radiographic examinations in the assessment of the pediatric patient.
- Respiratory distress
- Cardiac disease
- Pulmonary tuberculosis
- Foreign bodies
- Line placement location (e.g. Endotracheal tube).
- PA erect
- AP erect
- AP supine
- Lateral view and cross table lateral view
- To highlight pathology in the mediastinum, costophrenic recess and localize lesions.
Tips for Pediatric Chest Radiography
The challenges in acquiring radiographs in children are:
- Difficulty in achieving inspiration
- Likelihood of motion blurring
- Wide range of tissue densities
- Need to minimize radiation dose.
To overcome these:
- Attention diversion with toys, games, and/or conversation
- Immobilization with blankets and velcro straps
- Child-appropriate language.
IMPORTANCE OF DECUBITUS POSITION
Decubitus position: A position used in producing a radiograph of the chest or abdomen of a patient who is lying down, with the central ray horizontal.
The patient may be:
- Prone (ventral decubitus)
- Supine (dorsal decubitus)
- Left or right side (left or right lateral decubitus).
- Lateral decubitus view of the chest: To demonstrate small pleural effusions, pneumothorax, and inhaled foreign bodies.
- Side marking should be clearly labeled.
- In an ideal chest X-ray, lung fields should be visible from the apices down to the lateral costophrenic angles
- No superimposition of chin over any structures
- No superimposition of the scapulae borders on the lung fields
- Sternoclavicular joints at equidistance
- Clavicle should be in the same horizontal plane
- A minimum of nine posterior ribs should be visualized above the diaphragm
- Ribs and thoracic cage are seen only faintly over the heart
- Clearly visible vascular markings of the lungs.
Lateral Decubitus for Pleural Effusions
The fluid in the chest gets layered when the patient lies on the suspected side and can be viewed by chest X-ray in the lateral decubitus position is more sensitive and can detect as little as 50 mL of fluid. At least 300 mL of fluid must be present before upright chest X-rays can detect a pleural effusion.