A Passion for Precision: Zakithi Msimang’s Journey to Global Metrology Leader at IAEA

“Follow your passion, even if it isn’t clear.” This piece of heartfelt advice is more than just a motivational quote — it’s the guiding principle of Zakithi Msimang’s remarkable journey from South Africa to the International Atomic Energy Agency (IAEA) in Austria, where she currently serves as the organization’s only Secondary Standards Dosimetry Laboratory (SSDL) Officer.

Through her work, Msimang exemplifies the IAEA’s mission of Atoms for Peace and Development and highlights the transformative power of careers in STEM (science, technology, engineering and mathematics), particularly for women across the globe.

From Medicine to Metrology: Following Strengths and Curiosity

Msimang began her academic journey intending to become a physician. Yet, despite her dedication to studying biology, it was physics that came naturally. Recognizing her aptitude, she shifted her focus and graduated from the University of Forte Hare in South Africa with degrees in physics and mathematics.

Her entry into the specialized field of medical physics came through a postgraduate scholarship. Visiting hospitals and clinics during this period made her aware of the critical role medical physicists play in patient safety and treatment precision — particularly in oncology departments. Msimang committed herself to a two-year clinical training program, becoming a certified medical physicist responsible for calibrating radiotherapy machines and ensuring accurate cancer treatment planning.

Embracing the World of Metrology

After working in the clinic, an unexpected opportunity arrived — a position at South Africa’s National Metrology Laboratory in Pretoria. Though it was a lateral move, it offered a chance to build on her passion for calibration and measurement science. Initially working in electrical metrology, she was responsible for national standards in voltage and resistance, providing technical calibrations for industry and contributing to high-level advisory panels.

The turning point came in 2001, when a vacancy opened for a metrologist in ionizing radiation. Eager to reconnect with her roots in medical physics, she transitioned into the role. A regional IAEA training course introduced her to the Agency’s unified standards for dosimetry — a pivotal experience that expanded her vision and firmly established her future direction.

That moment led to her first formal engagement with the IAEA in 2003, when she joined the Dosimetry Laboratory in Seibersdorf, Austria, through a technical cooperation fellowship. While pursuing her master's degree, she gained international experience and insight into the global dosimetry landscape.

Climbing the Ranks: Leadership in National and Global Roles

Upon returning to Pretoria, Msimang rapidly advanced to group leader and eventually director of the radiation metrology division at the National Metrology Institute of South Africa. Her leadership responsibilities included strategic planning, securing national funding, and bridging the gap between laboratory capabilities and national health needs.

This experience laid the foundation for her next leap — joining the IAEA in 2020, right after earning her PhD in physics. Today, she plays a crucial role in supporting 89 laboratories across 76 countries in the IAEA/WHO Network of Secondary Standards Dosimetry Laboratories.

Her day-to-day responsibilities involve:

• Reviewing and validating global calibration data,

• Assisting countries in establishing dosimetry laboratories,

• Drafting IAEA guidance documents,

• Organizing training sessions on IAEA codes of practice.

Her mission is aligned with the theme of World Metrology Day 2025 — “Measurement for All”, reinforcing that consistent, accurate measurement is not just a scientific concern, but a global human right — whether it’s cancer patients receiving radiation or people buying flour.

An Advocate and Mentor for Women in STEM

As one of the few women at the intersection of physics, medicine, and metrology, Msimang is a powerful advocate for gender equality in science. She actively participates in the Marie Sklodowska-Curie Fellowship Programme (MSCFP), mentoring young women in nuclear-related fields. Her advice to young scientists — especially women — is clear: “Don’t let the pressures of life distract from following your heart. Understand your purpose and strive to fulfil it.”

The IAEA, recognizing the gender gap in nuclear science, launched MSCFP in 2020 to fund master's degrees for women in nuclear fields. In 2023, the Lise Meitner Programme was introduced to provide multi-week training visits to nuclear facilities for early- and mid-career women, opening more pathways for their career growth.

A Beacon for Future Generations

Zakithi Msimang’s journey is a testament to how following one’s curiosity and strengths can lead to a global career with deep humanitarian impact. Her role in harmonizing global radiation measurement standards ensures the safety and accuracy of medical treatments worldwide.

Her voice, her work, and her mentorship carry a powerful message to aspiring scientists: there’s a place for you in science — and it may be bigger than you ever imagined.