Diagnostic Imaging Modalities
Skeletal metastases can be evaluated by four clinical imaging modalities: plain film radiography, computed tomography (CT), magnetic resonance imaging (MRI), and skeletal scintigraphy.
Plain Film Radiography
Plain film radiographs are commonly used to evaluate symptomatic areas and to confirm findings seen with other imaging modalities. Because of its poor sensitivity (ie, 44% to 50% less sensitive than scintigraphy in detecting breast cancer metastases[3]), it is generally not used as a screening method.[3–5] Considerable bone destruction must be present before a bone metastasis is evident radiographically. An estimated 30% to 75% reduction in bone density is required for a lesion to be visualized on radiographs.[1] Moreover, the radiographic bone survey remains useful in the event of a "skeletal emergency," such as an impending pathological fracture, particularly of weight-bearing bones (Fig 2A). Radiography is invaluable for assessing the extent of cortical compromise and the risk of pathological fracture in tubular bones.[6] For example, lytic lesions that destroy 50% or more of the diaphyseal cortex can result in a 60% to 90% reduction in bone strength, significantly increasing the risk of fracture.[6] Radiographs are recommended for patients with symptoms of pain or tenderness that might be related to a weight-bearing bone (eg, femur or tibia).[6] The radiographic bone survey, however, remains important in staging of multiple myeloma due to poor sensitivity of scintigraphy in this condition.[4,6]

Plain radiography

Radiography is the use of x-rays to visualize the internal structures of a patient. X-Rays are a form of electromagnetic radiation, produced by an x-ray tube. The x-rays are passed through the body and captured behind the patient by a detector; film sensitive to x-rays or a digital detector. There is variance in absorption of the x-rays by different tissues within the body, dense bone absorbs more radiation, while soft tissue allows more to pass through. This variance produces contrast within the image to give a 2D representation of all the structures within the patient.
Common clinical applications * Chest: to assess lung pathology * Skeletal: to examine bone structure and diagnose fractures, dislocation or other bone pathology * Abdomen: can assess abdominal obstruction, free air or free fluid within the abdominal cavity * Dental: to assess common dental pathologies such as cavities or abscesses
Safety
* Radiography utilizes x-rays, a proportion of which are absorbed within the body. The potential effects on the body from ionizing radiation are categorized as deterministic (including skin reddening or burns) dependent on the dose or stochastic (long term effects such as cancer). * Due to the potential risk from ionizing radiation, exposures from radiography procedures must adhere to the ALARA principal; "as low as reasonable achievable" to obtain a diagnostic examination. * Special consideration should be given to pregnant women and children as they are more sensitive to radiation. * X-ray personnel should at all times ensure that the benefit of the examination will outweigh potential risk from radiation exposure, and that the patient is exposed to as little radiation as possible.

Mr Ben O'Sullivan
Prof Stacy Goergen
Date last modified: May 01, 2009

1. What is Plain radiography/X-rays?

Figure 1: Chest X-ray. Bone (collar bone and back) appears light grey. Air (lungs and stomach gas) appears dark grey.
Radiography is the imaging of body structures using X-rays. X-rays are a form of radiation similar to visible light, radiowaves and microwaves. X-radiation is special because it has a very high energy level that allows the X-ray beam to penetrate through the body and create an image or picture.
The image is created due to the X-ray beam being absorbed differently by different structures or parts in the body. A dense structure like bone absorbs a high percentage of the X-ray beam (which appears light grey on the image), whilst low density structures like soft tissues absorb a small percentage (which appears dark grey on the image). The body has many different structures of varying densities and this difference creates a picture or image (see Figure 1).

2. How do I prepare for Plain radiography/X-rays?
For a plain X-ray there are no specific preparation instructions but there are some important things you need to do: * Ensure you remember to arrive at the X-ray department with the X-ray order (request form or referral letter) from your doctor. This is a legal requirement and no X-ray examination can be performed without it. * Please inform your own doctor or the radiographer who is performing the X-ray if there is any chance you may be pregnant. This is important information as a different approach may be needed or even a different test altogether may be required. Safety of the patient and unborn child is the number one priority. * Be prepared to wear a hospital gown. This ensures the X-ray is of the highest quality as some clothing can make it difficult to see the images clearly. * Be prepared to remove certain items like watches, necklaces and certain types of clothing that contain metal objects such as zips, as these items may interfere with the quality of the image.

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3. What happens during Plain radiography/X-rays?
The following are the steps involved in a typical plain radiography/X-ray: 1. A radiographer (a trained X-ray technologist) will call your name and escort you through to an X-ray examination room. 2. They will explain the procedure and prepare you accordingly (as above). 3. Depending on the part of your body being examined the following will vary: * Your position (e.g. standing, sitting or lying) * The number of X-rays taken * The of the speed of the test 4. It is important that you stay completely still when the radiographer instructs you to, as any movement may create a blurred image. 5. After the X-rays have been performed, the radiographer has to process each X-ray and check the results for quality. This can sometimes take several minutes. 6. Sometimes there will be a need for additional images to be taken to obtain more information to help the radiologist make a diagnosis. There is no need for concern if this happens as it is quite common. In most cases the extra X-rays are performed to obtain a better view of your anatomy or body structure, not because there is a problem. 7. The radiographer will instruct you when the procedure is finished. You may wish to ask them when the results will be available. 8. A radiologist (specialist X-ray doctor) then carefully assesses the images, makes a diagnosis and produces a written report on the findings. This report is sent to the referring doctor, specialist or allied health professional who referred you for the test. 9. At any stage you are welcome to ask questions about the process if you have any concerns.
The entire process is straightforward and you will not feel anything strange or feel any different during the examination.
X-ray examinations are fast. Most procedures are quicker then 15 minutes (depending on the part of the body being X-rayed).

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4. Are there any after effects of Plain radiography/X-rays?
X-rays are invisible and you will not feel anything while the X-ray is being taken or afterwards.

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5. How long do Plain radiography/X-rays take?
It usually takes less than 15 minutes for an entire X-ray procedure. This obviously depends on the number of parts of your body being examined and your mobility, i.e. your ability to move about, and your general health. In most cases, the area being examined needs to be viewed from different directions to obtain enough information to make the diagnosis and this may require you to move into different positions.
For example, a simple chest X-ray on an able and willing patient could take less than 1 minute. However, a distressed patient needing a full spine, pelvis, both shoulders and both legs X-rayed could take 45 minutes.
People with disabilities and children will also take longer, particularly if they find it difficult to keep still or to cooperate with or understand instructions given by the radiographer (medical imaging technologist) who performs the X-ray examination.

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6. What are the risks of Plain radiography/X-rays?
Generally, the benefit of the X-ray procedure is far more important than the small estimated risk. At the radiation dose levels that are used in diagnostic radiography there is little or no evidence of health effects (see X-radiation (X-rays)– Radiation risk in general).
There are two major risks to health that occur as a result of exposure to medical ionizing radiation (which is the kind of radiation in X-rays). These are: * Cancer occurring many years after the radiation exposure; and * Health problems in the children born to people exposed to radiation because of damage to the reproductive cells in the body.
Medical research has as yet been unable to establish conclusively that there are significant effects for patients exposed to ionizing radiation at the doses used in diagnostic imaging. In addition, the dose of radiation that you receive from plain X-rays is very much lower than for other types of radiology procedures such as Computed Tomography (CT) scanning or angiography (X-ray examination of the blood vessels).
To put this all into perspective, a patient would need to have approximately 38 chest X-rays to receive an amount of radiation similar to that of normal background radiation that everyone receives for one year from the environment (ARPANSA 2008). This is very encouraging and supports the use of the small doses involved in diagnostic radiography.

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7. What are the benefits of Plain radiography/X-rays?
The benefits of plain radiography/X-ray are: * X-ray imaging is useful to diagnose disease and injury such as pneumonia, heart failure, fractures, bone infections, arthritis, cancer, blockage of the bowel, and collapsed lung, etc. * X-ray imaging is fast and easy so it is particularly useful in emergency diagnosis and treatment. * X-ray equipment is relatively inexpensive and widely available in hospitals and X-ray clinics and other locations, making it convenient for both patients and doctors, even in remote locations.
It is worth noting that Dr Brad Cassels (Manager, Radiation Safety, DHS) suggests that there haven’t been any hereditary effects observed in human populations (Monash Workshop 2007).

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8. Who does the Plain radiography/X-rays?
A radiographer or medical imaging technologist (MIT) is a health professional who performs diagnostic radiography.
A radiologist is a specialist medical doctor who reviews and interprets the images and provides a written report of the test to your referring doctor, specialist or allied health worker.

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9. Where are Plain radiography/X-rays done?
Plain radiography/X-rays are done in the diagnostic imaging department of most hospitals (although this depends on the size of hospital as some small hospitals do not perform X-rays). They can also be done at a private radiology practice.

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10. When can I expect the results of my Plain radiography/X-rays?
The time that it takes your doctor to receive a written report on the test or procedure you have had will vary, depending on: * the urgency with which the result is needed * the complexity of the examination * whether more information is needed from your doctor before the examination can be interpreted by the radiologist * whether you have had previous x-rays or other medical imaging that needs to be compared with this new test or procedure (this is commonly the case if you have a disease or condition that is being followed to assess your progress) * how the report is conveyed from the practice or hospital to your doctor (in other words, email, fax or mail)
Please feel free to ask the private practice, clinic, or hospital where you are having your test or procedure when your doctor is likely to have the written report.
It is important that you discuss the results with the doctor who referred you, either in person or on the telephone, so that they can explain what the results mean for you.

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11. Further information about Plain radiography/X-rays:
X-rays are safe when performed in a controlled environment like an X-ray department. X-ray equipment is checked regularly to ensure that it is functioning properly and not delivering excess radiation to patients or staff. People operating X-ray equipment are required by law to be licensed to do so, to ensure they are properly qualified to operate the radiation equipment.
If you require any more information or have queries about your X-ray procedure then please contact your local doctor or the hospital department/private radiology practice where you have been referred for the X-ray examination.

Plain radiographs are often called "plain X rays" - but you can't see the X-rays, only the images created by them. Radiographs can be produced using a variety of imaging methods, and they all require exposing the patient to X-ray radiation.
The image or picture is basically a shadow of the parts of the patient that absorb or block the X-Rays. The image can be collected on photosensitive film, on a digital imaging plate, or seen "live" on a fluoroscope - sort of like an X-ray TV camera.
The radiographic image is a "photographic negative" of the object - the "shadows" are white regions (where the X-rays were blocked by the object). The image is black in the regions that did not stop the Xrays, and they passed through to expose the film or sensor.
Plain radiographs ("plain films") are usually taken by a trained Registered Radiologic Technologist. The resulting films or images are then interpreted by the Radiologist to make a diagnosis or suggest further tests.

Radiography (Plain X-rays)
Despite the development of newer technologies such as computed tomography (CT), ultrasound imaging and magnetic resonance imaging (MRI), plain film X-rays remain an important tool for the diagnosis of many disorders. In radiography, a beam of X-rays, produced by an X-ray generator, is transmitted through an object, e.g. the part of the body to be scanned. The X-rays are absorbed by the material they pass through in differing amounts depending on the density and composition of the material. X-rays that are not absorbed pass through the object and are recorded on X-ray sensitive film (Figure 1) 1.

Fig. 1: The basic setup for X-ray imaging. The collimator restricts the beam of X-rays so as to irradiate only the region of interest. The antiscatter grid increases tissue contrast by reducing the number of detected X-rays that have been scattered by tissue.
While bone absorbs X-rays particularly well, soft tissue such as muscle fiber, which has a lower density than bone, absorbs fewer X-rays. This results in the familiar contrast seen in X-ray images, with bones shown as clearly defined white areas and darker areas of tissue (Figure 2) 2. This makes conventional X-rays very suitable for scans of bones and tissue dense in calcium such as in dental images and detection of bone fractures. Other uses of radiography include the study of the organs in the abdomen, such as the liver and bladder; chest radiography for diseases of the lung, such as pneumonia or lung cancer and mammographyto screen for breast cancer. X-ray fluoroscopy is used to detect a number of diseases associated with the stomach and intestine, genitals and urinary tract.

Fig. 2: A typical X-ray radiograph of the chest, in which the regions of bone appear white.
Traditionally, medical X-ray images were exposed onto photographic film, which require processing before they can be viewed and take up a lot of space in hospitals and doctors’ offices. Digital X-rays, which overcome these problems, have therefore become increasingly popular in radiography. Similar to a digital camera, an electronic detector is used instead of film. This “electronic image” is processed by a computer, enabling it to be stored digitally and viewed on screen immediately without processing.
X-ray imaging provides fast, high-resolution images and is relatively inexpensive. The average examination for most plain film examinations takes no more than 10–15 minutes and requires no special preparation of the patient. The operator, usually the radiographer (also known as a radiologic technologist), selects the amount and type of X-rays to be used according to the patient’s size, the tissue or part of the body being imaged and the amount of image contrast required. Because movement, e.g. of the lungs and diaphragm, blurs the image, patients are usually asked to hold their breath during the exposure. The X-ray picture is stored on a piece of film called a radiograph. These are interpreted by a physician specially trained to interpret them, known as a radiologist.
The ionizing radiation used in the production of X-ray images is carcinogenic and continuous exposure to these rays over time may cause damage to the body and increase the risk of cancer. However, experts consider the benefits of an accurate diagnosis and treatment to far outweigh the comparatively small risk involved in X-ray imaging.
Since the developing embryo is much more sensitive to the effects of ionizing radiation than adult patients, X-rays of any part of the body are not recommended for pregnant women. The risks of X-rays are greater for young children and unborn babies and the doctor will always bear this in mind when deciding on the need for medical imaging.
1. Modified according to: http://media.wiley.com/product_data/excerpt/63/04712376/0471237663.pdf (Last visited: Aug 17, 2011)
2. Courtesy of Klinikum St. Marien Amberg, Germany
Last updated: Mar 6, 2012

What is an x-ray?
X-rays use a special type of radiation to take pictures of bones and some parts inside the body, including the lungs. You will be asked to lie on a bed or sit down between the x-ray tube and a receiving plate which makes the picture.

A plain x-ray is used to look at bones for: * Fractures * Dislocated joints * Fluid around bones and joints * Infection * Bone growths * Bone diseases | Benefits of x-rays * Painless, fast and easy * No radiation is left in your body after the x-ray is finished |

Risks of x-rays
Your doctor knows the risks of having an x-ray. Your doctor will consider the risks before recommending you to have an x-ray. Possible risks are: * Not recommended for pregnant women * Very small chance you could develop cancer in the long term from the radiation.
Preparation
* Bring your referral letter or request form and all x-rays taken within the last 2 years with you * Leave the x-rays with the radiology staff as the doctor may need to look at them. The radiology staff will tell you when these are ready to be picked up * Leave all jewellery and valuables at home
Just before the x-ray * There is no special preparation for x-rays * You may be given a gown to wear * You may be asked to remove any metal objects
Important to tell your doctor before the x-ray * If you are or may be pregnant * If you have difficulty taking a deep breath and holding your breath
What happens during an x-ray?
X-ray staff will ask you to stand, sit or lie down depending on which part of the body is being x-rayed. Tell the x-ray staff if you have difficulty standing or sitting.

X-ray staff may place a protective shield over the parts of your body not being x-rayed, or you may be asked to wear a protective apron.

Once you are ready, the x-ray staff will go behind a screen or into the next room to start the x-ray machine. They will ask you to be still, and may ask you to take a deep breath and hold your breath during the x-rays.

When your x-ray is finished you will be asked to wait while the x-ray staff check the pictures, as you may need another x-ray.

The x-ray usually takes about 15 minutes including time taken to get ready.

Consent
You have the right to refuse an examination and may do so if you wish. A written consent is generally not required for plain x-rays.

When will I get the results?
The amount of time it takes for you to get your results will differ depending on where you get your scans done. The radiology doctor will look at the pictures and write a report. The pictures may be on films or on a CD.

Ask whether you should wait to take the pictures and report with you, or whether they will be sent to your doctor.

Your doctor will need to discuss the report with you. You will need to make an appointment to do this.

After the x-ray
You will be able to go soon after the x-ray is finished and can continue with normal activities.