Digital Imaging and Digital Imaging and Radiology Radiology

Traditional x-raysTraditional x-rays

Use electromagnetic waves to make picturesUse electromagnetic waves to make pictures

New imaging techniques use New imaging techniques use computers computers to to generate pictures of internal body organsgenerate pictures of internal body organs

Computers can make pictures using Computers can make pictures using mathematical informationmathematical information

Newer TechnologiesNewer Technologies

Computerized tomography is a diagnostic procedure Computerized tomography is a diagnostic procedure that uses special x-ray equipment to obtain cross that uses special x-ray equipment to obtain cross sectional pictures of the body.sectional pictures of the body.

The CT computer displays these pictures as detailed The CT computer displays these pictures as detailed images of images of organsorgans, bones, and other , bones, and other tissuestissues. .

In In cancercancer, CT is used to detect a , CT is used to detect a tumortumor, provide , provide information about the extent of the disease, help plan information about the extent of the disease, help plan treatment, and determine whether the cancer is treatment, and determine whether the cancer is responding to treatment responding to treatment

A A CT scanCT scan uses slightly more uses slightly more radiationradiation than a than a chest x-raychest x-ray, but the benefits generally , but the benefits generally outweigh the risks outweigh the risks

During a CT scan, the person lies very still on a table. The table slowly passes During a CT scan, the person lies very still on a table. The table slowly passes through the center of a large x-ray machine. The person might hear whirring sounds through the center of a large x-ray machine. The person might hear whirring sounds during the procedure. People may be asked to hold their breath at times, to prevent during the procedure. People may be asked to hold their breath at times, to prevent blurring of the pictures. blurring of the pictures.

Often, a contrast agent, or “dye,” may be given by mouth or injected into a vein Often, a contrast agent, or “dye,” may be given by mouth or injected into a vein before the CT scan is done. The contrast dye can highlight specific areas inside the before the CT scan is done. The contrast dye can highlight specific areas inside the body, resulting in a clearer picture.body, resulting in a clearer picture.

Magnetic Resonance Imaging Magnetic Resonance Imaging (MRI)(MRI)

MR imaging uses a powerful magnetic field, MR imaging uses a powerful magnetic field, radio waves and a computer to produce radio waves and a computer to produce detailed pictures of organs, soft tissues, bone detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. and virtually all other internal body structures. The images can then be examined on a The images can then be examined on a computer monitor or printed. MRI does not computer monitor or printed. MRI does not use ionizing radiation (x-rays).use ionizing radiation (x-rays).

In most cases, an MRI exam is safe for In most cases, an MRI exam is safe for patients with metal implants, except for a few patients with metal implants, except for a few types. People with the following implants types. People with the following implants cannot be scanned and should not enter the cannot be scanned and should not enter the MRI area: MRI area:

internal (implanted) internal (implanted) defibrillatordefibrillator cochlear (ear) implant cochlear (ear) implant clips used on brain clips used on brain aneurysmsaneurysms

Positron Emission TomographyPositron Emission Tomography

A PET scan, unlike a normal X-ray, can detect cancer A PET scan, unlike a normal X-ray, can detect cancer before organ or gland enlargement occurs. Here a before organ or gland enlargement occurs. Here a normal X-ray of the chest (left) is compared with a normal X-ray of the chest (left) is compared with a PET scan of the chest producing normal results (top PET scan of the chest producing normal results (top right) and a PET scan revealing cancer that's spread to right) and a PET scan revealing cancer that's spread to the lymph nodes (bottom right).the lymph nodes (bottom right).

Advantages of digital imaging Advantages of digital imaging

No developing processNo developing process Copies are as good as originalsCopies are as good as originals Viewed on computer screenViewed on computer screen Can be transmitted over telephone linesCan be transmitted over telephone lines Less radiationLess radiation More flexibleMore flexible Can be highlighted or enhancedCan be highlighted or enhanced

X-rays are most frequently used in orthopedics and dentistryX-rays are most frequently used in orthopedics and dentistry

As with many of mankind's monumental discoveries, As with many of mankind's monumental discoveries, X-ray technologyX-ray technology was was invented completely by accident. In 1895, a German physicist named invented completely by accident. In 1895, a German physicist named Wilhelm Roentgen made the discovery while experimenting with Wilhelm Roentgen made the discovery while experimenting with electron electron beamsbeams in a in a gas discharge tubegas discharge tube. Roentgen noticed that a . Roentgen noticed that a fluorescentfluorescent screen in screen in his lab started to glow when the electron beam was turned on. This response his lab started to glow when the electron beam was turned on. This response in itself wasn't so surprising -- fluorescent material normally glows in reaction in itself wasn't so surprising -- fluorescent material normally glows in reaction to electromagnetic radiation -- but Roentgen's tube was surrounded by heavy to electromagnetic radiation -- but Roentgen's tube was surrounded by heavy black cardboard. Roentgen assumed this would have blocked most of the black cardboard. Roentgen assumed this would have blocked most of the radiation. radiation.

Roentgen placed various objects between the tube and Roentgen placed various objects between the tube and the screen, and the screen still glowed. the screen, and the screen still glowed.

Finally, he put his hand in front of the tube, and saw the Finally, he put his hand in front of the tube, and saw the silhouette of his bones projected onto the fluorescent silhouette of his bones projected onto the fluorescent screen. Immediately after discovering X-rays screen. Immediately after discovering X-rays themselves, he had discovered their most beneficial themselves, he had discovered their most beneficial application application

Mammography is a traditional x-rayMammography is a traditional x-ray Mammography is a low-powered x-ray technique that captures Mammography is a low-powered x-ray technique that captures

a picture of the internal structure of the breast. Additional a picture of the internal structure of the breast. Additional angles and magnified views are taken of suspicious areas. angles and magnified views are taken of suspicious areas.

A mammogram may help in the diagnosis of breast problems, A mammogram may help in the diagnosis of breast problems, including cancer.including cancer.

It is recommended a woman have a baseline mammogram It is recommended a woman have a baseline mammogram

at age 40, followed by a at age 40, followed by a

mammogram every couple ofmammogram every couple of

years until age 50. years until age 50.

After 50, a woman should After 50, a woman should

have a mammogram every year.have a mammogram every year.

Ultrasound can distinguish between Ultrasound can distinguish between cysts and tumorscysts and tumors

It is used along with mammogramsIt is used along with mammograms

Does not use radiation but high frequency Does not use radiation but high frequency sound wavessound waves

Computer TomographyComputer Tomography

Uses x-rays and digital technology to produce Uses x-rays and digital technology to produce a cross-sectional image of the body. a cross-sectional image of the body. (Enhanced CT’s use dye)(Enhanced CT’s use dye)

Magnetic Resonance ImagingMagnetic Resonance Imaging

Produces images of soft tissue within the bodyProduces images of soft tissue within the body The image is produced by a computer with a The image is produced by a computer with a

magnetic field that is 25,000 times stronger magnetic field that is 25,000 times stronger than the earth’s magnetic fieldthan the earth’s magnetic field

Positron Emission Tomography Positron Emission Tomography (PET)(PET)

Scans can be two or three dimensionalScans can be two or three dimensional Used in the study of Alzheimer’s and Used in the study of Alzheimer’s and

Parkinson’s diseaseParkinson’s disease They produce pictures of activity and functionThey produce pictures of activity and function

Interventional RadiologyInterventional Radiology

Treats an ever-widening range of conditions inside Treats an ever-widening range of conditions inside the body from the body from outsideoutside the body by inserting various the body by inserting various small instruments or tools, such as catheters or wires, small instruments or tools, such as catheters or wires, with the use of various x-ray and imaging techniques with the use of various x-ray and imaging techniques (i.e., CT scanners, MRI scanners, ultrasound (i.e., CT scanners, MRI scanners, ultrasound scanners).scanners).

Interventional radiology offers an alternative to the Interventional radiology offers an alternative to the surgical treatment of many conditions and can surgical treatment of many conditions and can eliminate the need for hospitalization, in some cases eliminate the need for hospitalization, in some cases

Surgical biopsies have now been replaced with needle Surgical biopsies have now been replaced with needle biopsiesbiopsies

Stereotactic RadiosurgeryStereotactic Radiosurgery Stereotactic radiosurgeryStereotactic radiosurgery (SRS) treats brain disorders with a (SRS) treats brain disorders with a

precise delivery of a single, high dose of radiation in a one-day precise delivery of a single, high dose of radiation in a one-day session. Focused radiation beams are delivered to a specific area session. Focused radiation beams are delivered to a specific area of the brain to treat abnormalities, tumors or functional of the brain to treat abnormalities, tumors or functional disorders.disorders.

Is the very precise delivery of radiation to a brain tumor with Is the very precise delivery of radiation to a brain tumor with sparing of the surrounding normal brain.sparing of the surrounding normal brain.

Stereotactic Radiosurgery Stereotactic Radiosurgery cont.cont.

Uses a gamma knife which is a painless deviceUses a gamma knife which is a painless device

The gamma knife uses multiple beams of The gamma knife uses multiple beams of radiation converging in three dimensions to radiation converging in three dimensions to focus precisely on a small volume, such as a focus precisely on a small volume, such as a tumor, permitting intense doses of radiation to tumor, permitting intense doses of radiation to be delivered to that volume safely. be delivered to that volume safely.

Focused ultrasound surgeryFocused ultrasound surgery

Uses sound waves which create a powerful Uses sound waves which create a powerful ultrasonic beamultrasonic beam

High-intensity ultrasound energy focused on a High-intensity ultrasound energy focused on a small target volume raises the tissue small target volume raises the tissue temperature high enough to destroy it. This is temperature high enough to destroy it. This is similar to the manner in which sunlight focused similar to the manner in which sunlight focused by a magnifying glass can create sufficient heat by a magnifying glass can create sufficient heat to start a fire. The use of heat to destroy tissue to start a fire. The use of heat to destroy tissue is called thermal ablation is called thermal ablation