Our Team

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William Ratterree, DVM, DACVIM, DACVR

Board Certified Specialist in Medical and Radiation Oncology

Dr. William Ratterree is originally from South Carolina and pursued an Animal and Veterinary Science degree at Clemson University. He received his doctorate in veterinary medicine at the University of Georgia in May of 2008. He completed a small animal surgery and medicine internship at Louisiana State University, School of Veterinary Medicine in July of 2009.Dr. Ratterree stayed on at the Louisiana State University, School of Veterinary Medicine to complete a medical oncology residency in July of 2011. 

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He received his board certification by the American College of Veterinary Internal Medicine in May of 2012. A strong passion for treating small animal oncology patients with multimodality treatments led him to pursue a second residency in radiation oncology at Louisiana State University, School of Veterinary Medicine. He recently completed his radiation residency in July of 2013 and became boarded by the American College of Veterinary Radiology in September of 2013. With the unique background of being boarded in both medical and radiation oncology, it allows him to formulate multimodality treatment plans specifically for each patient keeping in mind quality of life and the human-animal bond. Dr. Ratterree has a special interest in combining newer radiation techniques (IMRT & SRS) for his patients in combination with chemotherapy and alternative techniques. Dr. Ratterree has headed the oncology, radioiodine departments at multiple veterinary hospitals in South Florida, serves as a radiation oncology consultant for multiple clinics nationwide, is adjunct oncology faculty at Louisiana State University, School of Veterinary Medicine and in addition holds the seat of Secretary for the Collier County Veterinary Society (CCVS).Dr. William Ratterree and Dr. Carrie Kosarek, husband and wife, are the founders of Fetch. They saw a great need for a specialized veterinary oncology center on the west coast and in June 2016 moved here from the east coast of Florida and opened Fetch at the Naples location in the Emergency Pet Hospital. In April 2017 they opened the second location in Bonita Springs, which is a state-of-the-art cancer center to include radiation therapy.When he is not tending to his local or distant patients, Dr. Ratterree is spending quality time with his family, his 2 cats, Luke and Leia and puppy Finn. During football season you will find him cheering on his favorite team, the Clemson Tigers! He also aspires to get his private pilot’s license.

Dr. Carrie Kosarek, DVM, MS

Diplomate ACVIM (Oncology)

Dr. Kosarek was born in Illinois but grew up in St. Petersburg, Florida and she attended The University of Florida for both her undergraduate and veterinary degrees. She graduated with her Doctorate of Veterinary Medicine in 1999 and continued her training at Florida Veterinary Specialists in Tampa, Florida as a rotating small animal medicine and surgery intern.

She then completed a one-year oncology internship prior to starting her medical oncology residency at The Ohio State University in 2001. Dr. Kosarek completed her residency and Masters of Science degree in 2004 and she became a Diplomate in the American College of Veterinary Medicine at that time.

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After working in Tampa, Florida as the staff oncologist for 2 years, Dr. Kosarek was a clinical assistant professor at the University of Georgia from 2006 – 2008. Dr. Kosarek moved back to Florida in 2009, where she held the position of an associate oncologist and intern director at Animal Cancer Care Clinic until March of 2016.

Dr. Carrie Kosarek and Dr. William Ratterree, husband and wife, are the founders of Cancer Veterinary Centers. They saw a great need for a specialized veterinary oncology center on the west coast and in June 2016 moved here from the east coast of Florida and opened Fetch Specialty & Cancer Veterinary Centers at the Naples location in the Emergency Pet Hospital. In April 2017 they opened the second location in Bonita Springs, which is a state-of-the-art cancer center to include radiation therapy.

When not treating her 4-legged patients with cancer, Dr. Kosarek enjoys spending time with her husband and their 10-year-old son. She also has 2 cats, Luke and Leia, and a puppy Finn who manages to keep her busy! She likes to stay healthy with pilates and cycling, but one of her favorite things to do with her son is birdwatching!

Education

  • Bachelors of Science, University of Florida
  • Masters of Science, The Ohio State University
  • Doctor of Veterinary Medicine, University of Florida
  • Diplomate, American College of Veterinary Internal Medicine
    Board Certified in Oncology

Dr. Tanya Gustafson, DVM, PhD

Diplomate ACVIM (Oncology)

Dr. Gustafson is originally from Dallas, Texas, Dr. She moved across the country to Boston, MA to attend Tufts University for her undergraduate degree in Biochemistry. She returned to her home state to complete her veterinary degree at Texas A&M University in 2009. She also received a Ph.D. in cancer research there concurrently. After graduation, she continued her training with a one-year general internship at the Animal Medical Center in New York, and a one-year oncology internship at Animal Cancer Care Clinic in Fort Lauderdale. Dr. Gustafson began her residency at Michigan State University and completed it through Colorado State University, leading to board certification in oncology. She returned to South Florida to practice oncology since 2015. During that time, she also directed an internship program in oncology and directed a clinical trials program. She has an interest in feline lymphoma and transitional cell carcinoma and recently published a study evaluating the use of Palladia in canine bladder cancer. When not at the clinic, she enjoys spending time with her husband and children visiting parks and museums. They also share their home with Neo, a playful Corgi mix. When possible, they love to go “glamping” at the beautiful Florida state parks.

Our Oncology Nurses

Amy

Radiation Oncology Nurse

Amy is originally from Quebec, Canada where she was born. She has lived in Florida for 15 years and in that time graduated from Edison State College in 2013 with an Associate Arts degree. From there she went on to earn her Associate of Science in Veterinary Technology with honors in 2015. Amy has always been interested in animals from domestic pets to large farm animals and even reptiles. Her desire to help animals brought her to Fetch Specialty & Cancer Veterinary Centers where she is an Oncology Nurse treating domestic pets. Since joining the team, she is now one of our radiation therapy nurses which has expanded her experience and responsibilities in oncology medicine.

Amy enjoys her free time with her. She also likes to stay mentally and physically healthy with reading, working out, and having good meals!

Shannon

Medical Oncology Nurse

Shannon was raised in Naples Florida but was born in East Longmeadow, Massachusetts. While going to school for a teaching degree, she realized that her passion really was helping animals. She quickly changed career paths and focused on the general veterinary practice field. She worked in general practice for 8 years and from there went into specialty medicine and joined ER. In 2016 she moved into neurology and then into oncology where she took a special interest in. She felt this specialized area of veterinary medicine was the most challenging, yet the most rewarding. If there is any one area she could say is most intriguing to her in oncology, she would have to say brain tumors and lymphoma. Shannon’s 11 years of general and specialty experience as well as her true passion for veterinary oncology brought her to Fetch Specialty & Cancer Veterinary Centers where she works as an Oncology Nurse. She is currently studying at Penn Foster to receive her CVT license.

In her personal time, Shannon shares her life with her husband TJ, their horse Partner, Shelby their Australian Shepherd and Chitty the cat! She finds her relaxation at the barn with her family horses or doing water activities.

Michelle

Lead Medical Oncology Nurse

Michelle was born and raised in Florida. She was born in West Palm Beach, was raised in Orlando and moved to Fort Myers in 2009. She has worked in veterinary medicine since 2006. Michelle spent 4 years in veterinary internal medicine before she decided to pursue veterinary oncology. Her special interest in lymphoma in pets not only helped with that decision, but it is what brought her to Fetch Specialty & Cancer Veterinary Centers as a Medical Oncology Nurse. She sees many patients with lymphoma successfully go into remission and do well and this is gratifying to her. As a Lead Medical Oncology Nurse, she wears many hats and performs tasks in many areas such as; chemotherapy, CT scans and x-rays along with doing inventory and just the day to day duties.

Michelle and her son enjoy their time together with their Pitbull, Dixie. Outside of spending time with her son, she enjoys going to the beach and sipping wine!

Terri

Medical Oncology Nurse

Terri is originally from Alaska where she was born and lived until 2003. Prior to her moving to Florida in 2018, she lived in Idaho, Washington, California, and Las Vegas, Nevada. It was in Las Vegas where she earned her Veterinary Assistant Certificate from Pima Medical Institute in 2014. She then passed her VTNE and received her Veterinary Technician license in the Fall of 2014.

Terri was inspired to become a Veterinary Technician simply by watching Animal Planet on TV! Watching people help and save lives of animals was what she had a passion to do. She came to Fetch Specialty & Cancer Veterinary Centers as a Medical Oncology Nurse after 7 years in the general practice veterinary field. She wanted to be in specialty care and cancer was the specialty care she wanted to pursue. There isn’t really one particular thing she enjoys most about working in cancer specialty, she says she loves everything about treating patients. Her primary responsibilities at Fetch are the duties of a Medical Oncology Nurse, assisting with CT scans, and Radiation Therapy.

When she is not treating patients at work, she is spending quality time with her daughter and family going on road trip adventures, enjoying the beach and collecting shells as well as reading. Terri and her daughter have 2 cats of their own.

Jess

Oncology Nurse Assistant

Jessica (Jess) is a native to Florida originally from Fort Lauderdale. Her role at Fetch Specialty & Cancer Veterinary Centers is an Oncology Nurse Assistant where she assists our Veterinary Oncologists as well as our Medical Oncology Nurses with the day-to-day care of patients. Jess is currently studying for her certification as a Certified Veterinary Technician. Her care for our patients and willingness to assist our medical team is appreciated in all departments of Fetch.

In her personal time, Jess is very busy with her 2 sons and the various pets they have; 3 dogs, 4 cats, 4 tortoises, 1 snake, and a bearded dragon. Jess will tell you that in her free time she enjoys time with her boys, cleaning and taking her children from one sports practice to another!

Elizabeth

Medical Oncology Nurse

Elizabeth grew up in Indiana but lived in South Carolina and California for a while before moving to Florida in the summer of 2019. She started her career in general practice veterinary medicine in 1999. After 12 years in general practice, she moved into specialty veterinary medicine.

Her love for animals and wanting to make a difference in an animal’s life with cancer brought her to Fetch Specialty & Cancer Veterinary Centers as a Medical Oncology Nurse. Elizabeth equally enjoys getting to know the patient’s owners and making their experience the best they can have while seeing their pet through cancer treatments.

In her personal time, Elizabeth enjoys spending time on the soccer field with her son and daughter. She and her family very much enjoy outdoor activities like the beach and swimming. She is also a mom to a pitbull/boxer mix, Mia.

Our Client Service Representatives

Dena

Customer Service Representative

Dena is originally from Connecticut and has been in Florida since 1991. She received her medical assistant certificate from Edison Community College in Florida. Through the U.S Career Institute, she received her certificate in medical coding. As one of Fetch Specialty & Cancer Veterinary Centers Customer Service Representatives, her smiling face greets our patients as they walk through the doors. Dena’s 20 years of experience in the human medical field as a CSR and her love of animals brought her to Cancer Veterinary Centers. Her natural talent for such friendly and sincere compassion for clients and patients is a warm feeling upon arrival and departure. She is also one of the pleasant voices on the other end of the phone when our clients call our office.

Dena spends time with her son and their dog Oreo who is a border collie mix. She enjoys relaxing with a bike ride, shopping, or going out to dinner with family and friends. One of her most interesting hobbies is attending fan conventions where she gets the opportunity to meet her favorite actors! It is there that she collects celebrity items, autographs, and pictures with the celebrities.

Karina (Kari)

Customer Service Representative

Kari is originally from Corozal, Puerto Rico, and moved to Florida recently. She has joined Fetch Specialty & Cancer Veterinary Centers as a Client Service Representative where she assists in the welcoming and caring customer service we pride ourselves on. Kari’s love for animals, as well as people, is felt by our clients as they walk through the front doors. Kari enjoys being able to spend time observing the different areas of treatment offered at Fetch so she can expand her veterinary medicine knowledge.

In her personal time, she loves to spend as much time as she can with her 2 daughters. She likes to watch movies on Netflix as well as seeing good movies at the movie theater, going to the beach and hanging out with her family.

Kayla

Customer Service Representative

Kayla grew up in a military household and moved to different areas, lastly Pennsylvania until she recently moved to Florida. She has joined Fetch Specialty & Cancer Veterinary Centers as a Customer Service Representative as a way to learn more about specialty care and in particular oncology. Her interest in veterinary medicine began with her first cat, Miss Mimi. With several visits to the vet’s office with Mimi’s health issues, she decided she wanted to be part of helping animals and went to work for a veterinary practice. Over the last 6 years, she has become certified as an abdominal ultrasound technician/ultrasonographer for small animals.

Kayla studied secondary education and mathematics at Temple University then transferred to The University of Pittsburgh to study biological sciences. She will complete her Bachelor of Science degree in Business Health Services Management at Temple University.

In her free time, Kayla enjoys spending time with her 2 dogs, Maple, a rottweiler, Charlie, a mixed breed, and 6 cats. She also likes fishing, binge-watching TV shows, reading, and relaxing on the beach with a good book!

Our Office Administration

Ellen

Financial Manager

Ellen was born in Texas but moved around quite a bit in the U.S as well as Europe before she settled in Florida. She received her Bachelor’s degree in pre-veterinary medicine from the University of Delaware and her Master’s degree in biomedical and genetic engineering at Drexel University and Villanova. She then went on to get her MBA from Penn State University.

Ellen has worked full time in general veterinary medicine for 20 years. Her passion to spend her career life in the veterinary industry started at the age of 12 when she worked in veterinary practices in the kennels and on horse farms. Ellen worked as a veterinary technician and moved into a practice management position. She brings over 21 years of experience to Fetch Specialty & Cancer Veterinary Centers in her role as the Financial Manager. Her extensive veterinary knowledge and ability to manage a team of employees with harmony is a strength for Ellen. There is not an area of the practice she cannot assist with at any given time.

In her private time, you will find Ellen enjoying time with her son and their dog Darcy, a golden retriever mix, 2 cats, and a macaw. She enjoys being physically active by going to the gym, weightlifting, playing pickleball, and tennis. For relaxation, she likes to go boating and having brunch with friends.

Alesia

Practice Manager/Marketing Outreach Coordinator

Alesia is originally from Syracuse, New York, and has lived in Florida for many years. She brings with her over 15 years of experience in the marketing and sales industry. She comes to Fetch Specialty & Cancer Veterinary Centers from the Country Club business, where she served as a Director of Sales and Marketing for 15 years.

She is also the President and founder of Golden Retriever Rescue of Southwest Florida, Inc. It is through the rescue Alesia first met Dr. Kosarek and Dr. Ratterree and a good working relationship between Fetch Specialty & Cancer Veterinary Centers and the rescue began. Alesia comes to Fetch with a great passion for animals and good medical knowledge as a medical coordinator for the rescue. Through the rescue, she has also developed good working relationships with many of the local veterinarians in the area.

Alesia has a dual role at Fetch; she is the Practice Manager where she oversees daily operations, staff management, and client relationships ensuring patients and their families have a positive Fetch experience. She is also the Marketing Outreach Coordinator where she manages the outreach and community engagement activities of Fetch. She keeps all of the local veterinary hospitals and pet owners up-to-date on all that Fetch has to offer their patients and pets in cancer care.

In her free time, you will find her working hard in the Golden Retriever Rescue of Southwest Florida. She also spends as much time as possible with her husband and their 5 dogs; Bo, Riley, Stormy, and Willow who are golden retrievers and Monty a yellow lab.