The Difference Between Diagnostic Radiology, Radiation Therapy and Interventional Radiology

radiation therapy

At first glance, these three disciplines within veterinary medicine seem pretty much the same, but at the Animal Medical Center, diagnostic radiology, radiation therapy, and interventional radiology represent three different groups of veterinarians with three very different sets of background and training. What ties these three disparate groups together is their use of radiation to diagnose and treat disease.

Diagnostic Radiology
These days you are more likely to find a Department of Diagnostic Imaging in a hospital than a Radiology Department. Radiology is an older term, used when x-rays were the only testing modality using radiation available in medicine. Today, AMC’s Diagnostic Imaging Service uses not only traditional x-rays but also ultrasound, computed tomography (CT) scans, and magnetic resonance imaging (MRI) in the diagnostic evaluation of patients. AMC’s Diagnostic Imaging Service also has a fluoroscopy unit, which is like a video x-ray. This machine allows us to watch bodily functions like blood flow or swallowing in real time. To see an example of fluoroscopy, read about Molly the Ganaraskan. Every veterinarian at AMC depends on our diagnostic imaging team for their expertise in imaging sick pets and helping us to make an accurate diagnosis.

Radiation Therapy
A very accurate description, AMC’s Radiation Oncology Service uses radiation to treat tumors. Specifically, we have a linear accelerator (linac), a giant machine that creates various types of radiation depending on patient needs. Our state-of-the-art linac can make electrons for superficial treatments, produce high energy pinpoint beams for stereotactic radiosurgery, and stereotactic body radiation therapy. Diagnostic Imaging’s CT scanner interfaces with Radiation Oncology’s 3-D computer planning system. The interface allows the linac’s multileaf collimator to sculpt the radiation beam to precisely target the tumor being treated. The veterinarians working in radiation therapy have training in both the physics of radiation as well as the management of cancer.

Interventional Radiology
Specialists in interventional radiology use minimally invasive techniques to make image-guided diagnoses and also deploy high tech treatments for a variety of diseases. Using a range of techniques which rely on the use of images generated by diagnostic radiology equipment such as fluoroscopy, ultrasound, CT scan, or MRI imaging, the interventional radiologist precisely targets various organs with treatments such as stents, occluders and medications. Watch a video where AMC’s interventional radiology team uses fluoroscopy to close off abnormal blood vessels in the liver. The veterinarians in our Interventional Radiology Service have diverse backgrounds in surgery, internal medicine plus specialized training to use minimally invasive equipment.

Linked together by their use of radiation as a diagnostic and therapeutic tool, diagnostic radiology, radiation therapy and interventional radiology are just a few of the highly trained specialists at AMC working to make sick pets healthy again.

Veterinary Interventional Radiology & Interventional Endoscopy

interventional radiologyInterventional Radiology and Interventional Endoscopy are well established tools in human medicine. The Animal Medical Center is the first veterinary facility to implement a complete interventional service. Our interventional veterinarians refine procedures currently used in people, tailoring the tremendous potential of these techniques to treat serious pet maladies. Examples of the disorders treated interventionally here at the AMC include:

Veterinary Interventional Radiology

Interventional radiology involves the use of contemporary imaging methods (primarily video x-ray, called fluoroscopy) to gain access to different structures of the pet’s body for diagnostic and therapeutic reasons without the need for traditional surgery.

Veterinary Interventional Endoscopy

Interventional endoscopy involves the use of endoscopes, small cameras which can be guided throughout the body via naturally existing orifices, often in conjunction with other contemporary imaging modalities, such as ultrasound or fluoroscopy. Guided by these images, the clinician can reach most parts of the body without the need for open surgery.

Using these modalities, The AMC provides non-surgical alternatives to many disease processes thereby:

  • Decreasing mortality rates
  • Minimizing anesthesia time
  • Reducing hospital stays
  • Lowering costs
  • Providing alternative options for pets

By offering interventional medicine to our clientele, we are providing options to patients in whom conventional therapies are declined, not indicated or associated with excessive morbidity or mortality. Additionally, some of these techniques present treatment opportunities for patients with various conditions for which there may not be standard remedies.

The interventional service offers care to a wide range of patients – from pocket pets to zoo animals! Please don’t hesitate to contact us if you think your pet might benefit from our help.

Support New Procedures

You can help provide the much needed philanthropic support to perfect such procedures. Your support of this program will enable The Animal Medical Center to continue to be a center of excellence in minimally invasive procedures and provide training to interested veterinarians around the world.

Human and Veterinary Doctors Collaborate

Thanksgiving dinner was just too tempting to pass up for an eleven year old Weimaraner named Gretel. The result of eating what was to be the family’s holiday meal turned out to be a severe case of pancreatitis. Gretel’s owners, seeing their dog in pain, took her to their local veterinarian in Philadelphia who had her hospitalized several times in their attempts to help her recover. Unfortunately, despite their valiant attempts, Gretel’s condition got progressively worse. Over a period of several weeks, Gretel developed scar tissue to the outflow tract of her bile, called the common bile duct. This resulted in a severe biliary obstruction causing her bilirubin levels to rise to a dangerously high level in her blood. The surgical and critical care specialists in Levittown, Pennsylvania were hesitant to operate on Gretel knowing the risks of this type of surgery. They called Drs. Allyson Berent and Chick Weisse at The Animal Medical Center to discuss placing a biliary stent endoscopically, a procedure called ERCP or endoscopic retrograde cholangiopancratography. This was considered as an attempt to un-obstruct her biliary tract without doing the invasive surgery, which can be met with major complications.

Drs. Berent and Weisse had some experience with conducting this procedure prior to joining The AMC, however, the procedure they conducted was performed in a research setting with the help of a human gastrointestinal interventionalist. These doctors had never performed and ERCP on a clinically ill patient like Gretel. This procedure is very difficult and, in humans, expertise is needed before this should be attempted. Drs. Berent and Weisse knew they needed a special endoscope and stents, as well as the expertise of a human physician to assist them if they were to successfully conduct this procedure on Gretel.

Over the last several years while practicing at The AMC, Drs. Berent and Weisse have developed close working relationships with the doctors at Memorial Sloan-Kettering Cancer Center (MSKCC), as well as with representatives from Olympus and Boston Scientific, who provided the required scoping and stenting equipment needed for an ERCP. With the help of the highly responsive physician, Dr. Mark Schattner, all the pieces came together to help Gretel.

Gretel’s owners were pleased to know their dog would not have to undergo open surgery if this were successful, and were willing to take the chance using a non-invasive procedure, even though it was still untested in a clinical setting for veterinary patients.

On December 13, 2012, nearly three weeks after Gretel became ill, a biliary stent was placed in Gretel endoscopically. This was accomplished in a period of 26 minutes, thanks to the expertise of the GI interventionalists at MSKCC, Drs. Schattner, Gerdes and Tilara. Gretel’s condition improved immediately, her bilirubin levels dropped precipitously, and she wanted to eat right away. She was reunited with her owners and went home three days later, and has continued to eat ravenously.


The doctors are so pleased with her outcome, and the immediate success of this procedure, that they are currently recruiting more cases with Gretel’s condition to try and help in a similar way. The doctors at MSKCC are eager to continue to collaborate with Drs. Berent and Weisse and make a biliary intervention program a reality at The Animal Medical Center.

Managing Tracheal Collapse in your Dog

A Facebook friend of The Animal Medical Center posted a question asking how they might prevent tracheal collapse in their dog. Unfortunately, tracheal collapse may not be preventable, but dog owners can help lessen the impact of a collapsing trachea on their dog’s quality of life. Since tracheal collapse is an important problem in dogs and is likely to flare up more now that spring is here, I have expanded on my Facebook response for the readers of Fur the Love of Pets.

The problem

If you are a large dog owner, you may not know what tracheal collapse is since the disorder is most common in toy and miniature breed dogs – Chihuahuas, Pomeranians, Poodles, Shih tzus, Lhasa apsos, and Yorkies. In a normal dog, the tubular shape of the trachea comes from cartilage in the C-shaped tracheal rings. The two ends of the C are joined by a soft membrane completing the circle. In dogs with tracheal collapse, the cartilage loses it rigidity and becomes flabby. The flabby rings pull on the soft membrane, stretching it and flattening the tubular trachea into an oval with a narrow inner dimension. With each inspiration, the flabby trachea collapses, producing noisy respirations and a cough. Sometimes the cough progresses to full-blown respiratory distress requiring a trip to the animal ER for a stay in an oxygen cage pictured above.

Weight control

Overweight dogs have more difficulty breathing and being overweight contributes to the chronic cough typical of tracheal collapse. If your dog is already overweight, see your veterinarian to develop a plan of diet and exercise to take off the extra pounds. In a small dog like a Yorkie, 1/4-1/2 pound of weight loss may make a big difference.

Change your restraint method

Use a harness and not a collar when walking your dog. You may want a collar for the ID tags (and don’t forget the microchip too) but hook the leash to a harness, which pulls less on the throat and neck. Less pulling usually means less coughing.

Avoid heat and humidity

As the weather warms up and the humidity climbs, owners of dogs with tracheal collapse will begin to worry about the impact of heat and humidity on their dogs’ respirations. When it is hot outside your dog should be inside if she is one with tracheal collapse. Every veterinarian will tell you when the humidity is up, coughing increases and the oxygen cages in animal ERs are full. To prevent your dog from being in the ER oxygen cage, take them out only in the cool of the early morning or late evening to avoid provoking coughing spells instigated by breathing heavy, wet summer air. Keep your dog in the air conditioning on days the air can be cut with a knife.

For other tips to prevent heat-related health issues in your pet, click here.