For the media

Dosimetry: targeting cancer behind the scenes

By The Health News Team | October 23, 2019
Dosimetry: targeting cancer behind the scenes

Dosimetrist Mallory Stulga develops radiation therapy treatment plans to kill tumors while protecting healthy tissue and organs.

In most hospitals, it’s clear what a doctor or a nurse does. However, if someone were to ask you what a dosimetrist does, you may not have an answer.

A dosimetrist plays a vital role in treating people diagnosed with cancer who may require radiation therapy to cure or treat their disease. Dosimetry refers to the science of measuring and calculating the correct radiation dosage directed at a tumor to kill cancer cells.

“A dosimetrist works behind the scenes and is part of a patient’s radiation oncology team,” says Mallory Stulga, a dosimetrist who works at Sharp Grossmont Hospital.

Treating cancer with pinpoint accuracy
While a radiation oncologist heads up the team and prescribes a patient’s course of therapy, the dosimetrist provides the precise calculation to pinpoint cancer in the body so surrounding tissues and organs stay healthy. The end result is a 3D image showing exactly where the beams of radiation will safely enter and exit a tumor.

“Even though dosimetrists work in the background and not directly with patients, it’s extremely rewarding to feel confident that each treatment we deliver is worked on in-depth and calculated to be the best plan possible for each patient,” says Stulga.

“Most patients don’t even know dosimetrists are a part of the radiation oncology team, but some patients are curious and stop by my office to check out their plan. They’re always amazed by what we do and are grateful for all the time spent on each case, and that makes it even more rewarding,” she says.

Stulga offers some insight into the field of dosimetry and the important role it plays in helping patients with cancer.

Why is dosimetry important?
Dosimetrists have broad knowledge of the overall characteristics and clinical relevance of radiation treatment machines and equipment, and we provide precise radiation dose distributions and calculations. Our job is a delicate balance between delivering the radiation dose prescription and ensuring the patient will not lose important healthy organ function.

What role does a dosimetrist play in a cancer patient’s overall health team?
The dosimetrist designs the treatment plan for each patient. After the radiation oncologist consults with the patient on their plan of treatment, they write a prescription of radiation dose to a defined tumor volume. The dosimetrist designs a treatment plan by means of a computer to deliver the prescribed dose while taking into consideration the dose to dose-limiting structures. These structures could include the eye when treating the brain, the heart when treating the lung, or the spinal cord when treating that particular area.

What technology is involved?
The advancements in computer technology places us at the forefront of many new processes. Using imaging such as CT scans — alone or in combination with MRI or PET scans — we plan with 3D computer software that enables us to give higher doses of radiation to a tumor while lowering the doses to the sensitive structures around it.

Any special certification or education required for dosimetry?
Typically, you must complete a four-year college degree, preferably in the physical sciences, followed by a graduate degree in medical dosimetry. Once schooling is complete, dosimetrists must become a certified medical dosimetrist (CMD) by passing an exam issued by the Medical Dosimetry Certification Board — the recognized certifying agency for medical dosimetry in the U.S.

Learn more about advanced cancer treatment options at the Cancer Centers of Sharp HealthCare.

For the news media: To talk with Mallory Stulga about the science of dosimetry for an upcoming story, contact Erica Carlson, senior public relations specialist, at

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