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About us

At Sirona, we stand by our promise of providing the very best patient care. Our friendly and knowledgable staff is on hand to help answer your questions and concerns.

Laura Pak, M.D.


Dr. Pak grew up in Dallas, Texas and graduated Magna Cum Laude from Harvard University with a major in English. She attended University of Pennsylvania for medical school and did a research fellowship in Cardiac Transplantation at Texas Heart Institute in Houston, Texas. She completed a General Surgery residency and Interventional Radiology and Vascular Surgery fellowships at UCSF. Before going into private practice in Marin, she was an Assistant Professor in the Division of Vascular Surgery at UCSF. She has authored numerous peer reviewed papers and chapters, was a founding member of the Young Surgeons Advisory Board of the Society of Vascular Surgery (SVS) and currently serves on the SVS Community Practice Council. 



Tina Desai, MD 

Dr Desai grew up in Chicago. She earned her MD at Brown University and then completed General Surgery residency, a vascular Surgery fellowship, and a Medical Ethics fellowship at University of Chicago.  Before moving to the Bay Area, she served as an Assistant Professor and Director of Endovascular Services at University of Chicago until 2010 and then joined the Division of Vascular Surgery at Northshore University Health System. Her published research is on the topics of IVC filters, mesenteric ischemia, and ethics of delivery of health care. She has also consulted in the development of structured reporting for EMR. She is a competitive tennis player and a discriminating enophile.

Wanda Zhao, PA-C


Wanda was born in a small village in the Canton province of China and emigrated to the U.S. with her family at the age of 7. She grew up in San Francisco and attended college at Loyola Marymount University, where she graduated with honors and received accodades as a Department Scholar. She did her P.A. training at Duke University and then a Surgical P.A. residency at Norwalk/Yale University. This year she celebrates her fifth year in our practice. She is a competitive volleyball player and also enjoys eating out, cooking and entertaining. She is fluent in Chinese. She says she works at Sirona because "I love the people I work with. It is rewarding to see the positive impact of what we've done for other people."

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Brandon Wong, PA-C 

Brandon grew up in living in San Francisco. He attended University of California, Santa Cruz and graduated with a baccalaureate degree in Marine Biology. He completed his Physician Assistant training at Clarkson University in Potsdam, NY. He graduated with honors, served as the P.A. class president and was inducted as an honorary member to the National Honor Society for Physician Assistants.  Outside of work, he enjoys spending time with his family and cooking food with his wife.



Mei Dan, BS, RVT

Mei was born in Beijing, China. She came to the U.S. as a foreign exchange student at the age of 17. She attained her BS in Information Systems and the in Vascular Ultrasound at Oregon Institute of Technology. She completed internships at San Jose Medical Group in echocardiograms and then at Highland Hospital in vascular ultrasound. She worked at the Center for Cardiovascular Care in San Jose and Health Diagnostics before joining Sirona. She is fluent in Mandarin and has her BLS certification.  She says, "Many times patients ask me if I enjoy what I am doing. I always respond proudly with a yes.  I enjoy the fact that my job contributes in part to their diagnosis. I enjoy helping people and putting a smile on their face. I consider patients that I see regularly as part of family."



Lisa Nguyen, BS, RVT

Lisa was born in Ho Chi Minh, Vietnam. She came to the U.S. in 1992 and was raised in Beaverton, Oregon. She attained her BS in Vascular Technology at Oregon Institute of Technology. She worked at Lake Washington Vascular in Bellevue, Washington and at Vascucare Kaiser in Oakland before joining Sirona. She is fluent in Vietnamese and also is CPR certified. She has also been involved in clinical trials for perforator ablation and for sclerotherapy for varicose veins. Her coworkers remark on her calm demeanor, her professionalism and her go-to attitude. And she makes excellent shrimp toast.



Kayla Richardson, MA 

Kayla was born and raised in Petaluma, CA. She completed the Medical Assistant program at Boston Reed College in Santa Rosa, and then worked at the Coastal Health Alliance (CHA) clinics in Point Reyes Station, Bolinas and Stinson Beach. She says she enjoys working at Sirona Vascular Center because "my coworkers and I share the same common goal, to provide the highest level of care to our patients in a comfortable environment." Outside of work, she enjoys traveling and wine tasting. She is also a huge San Francisco Giants fan. One of her coworkers said of her: "I admire how genuinely and honestly nice she is and I really do find myself stopping to think 'How would Kayla handle this?' and then attempting to follow that course."



Berenice Cobb, MA 

Berenice was born in Palo Alto and was raised in the South Bay. She did her MA training at the Institute for Business and Technology and also earned an EMT certificate at San Jose City College and completed PA prerequisites at Foothill College. She has 13 years of experience in the medical field, including at Saratoga Walk in Clinic and Santa Clara Urgent Care. Coworkers note that she is always reading to expand her knowledge base. She is a faithful 49ers fan and plays fantasy football. She says she likes working at Sirona becuase "It's a wonderful group that shares one common goal: to provide the highest level of care."



Kim Figone, MA/Front Desk

Kim grew up in South Africa and came to live in Petaluma in 1986. She has 25 years of experience as a Medical Assistant. One of the opportunities which most shaped her medical career was a year long traveling fellowship assisting in medical clinics in Hong Kong, India, Kenya and the Philippines. Outside of work, she is an avid runner and cyclist and enjoys competing in local races and triathlons. Of her work, she says, "I enjoy interacting with our patients and knowing at the end of the day I have touched a life or two with kindness and compassion. That's fulfilling."



Seng Phomsouvanh, Clinical Coordinator

Seng was born in Laos and immigrated to the United States with her family in 1980.  She is one of five children and was raised in the Bay Area. She graduated from Richmond High School and received a diploma in Medical Assisting from Bryman College. She has been in the healthcare field for over 10 years and coordinated plasma donations and cardiology procedures before joining Sirona. She is fluent in Lao. She says she enjoys working at Sirona "because I like to help people. I like to be able to ask questions and have a direct working relationship with the providers." She is widely regarded as Dr. Pak's boss.


Evelyn Shapiro, Operations Coordinator 

Evelyn grew up in San Francisco. She earned a Bachleor of Science in Kinesiology at San Francisco State University. Before joining Sirona, she served as the Administrator at the Marin Specialty Surgery Center and was well known as "the rock that holds the place together."  She has multi-varied talents outside of work, including salsa dance, double dutch jump rope, hair braiding, and martial arts. She has attained first degree brown belt in Shaolin Kenpo. She says, "I feel fortunate to be part of the Sirona Vascular team. There is a sense of loyalty that stems from the staff as well as the patients. I feel motivated to work in an environment that puts the quality of care of the patients first."

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