September 5, 2019 — Heidelberg University Hospital, Germany, has treated its first patient using Monte Carlo photon dose planning in RayStation. The decision to go clinical was made after a thorough validation of the functionality. The first patient, who has cervical cancer involving the lymph nodes, was recently treated.
In April 2018, RayStation was selected for particle therapy treatment planning in a joint decision by clinicians and researchers at Heidelberg Ion Beam Therapy Center (HIT), Heidelberg University Hospital and the German Cancer Research Center (DKFZ). Heidelberg University Hospital extended its RayStation installation for photon beam therapy in July 2018, strengthening the existing partnership with RaySearch. The order reflects the hospital’s aim of adopting RayStation as its sole treatment planning system, consolidating several legacy systems.
A vital feature in a treatment planning system is the ability to calculate the radiation dose a patient would receive during a proposed treatment. This involves modeling the components of the treatment machine, the patient’s anatomy and the radiation beam itself. RayStation 8B introduced the Monte Carlo dose calculation method for photon radiation, based on the well-known Monte Carlo algorithm, which is widely regarded as the gold standard for dose calculation.
The drawback of Monte Carlo has traditionally been prohibitively long calculation times. However, the graphics processing unit (GPU)-based dose engine in RayStation overcomes this limitation. As an example, the dose for a dual-arc volumetric modulated arc therapy (VMAT) plan can be computed in less than 30 seconds – faster than any other system on the market, according to RayStation. The Monte Carlo dose engine can also be used to calculate dose during optimization of the treatment plan, which can improve accuracy.
Heidelberg University is the oldest university in Germany; its first medical lectures were held in 1388. Today, Heidelberg University Hospital is one of the largest and most prestigious medical centers in Europe, with a reputation based on excellent patient care, research and teaching. The hospital offers inpatients and outpatients innovative and effective treatment for all complex diseases. Modern buildings with state-of-the-art equipment deliver medical care to the highest international standards. Proximity and interlinking of the specialist departments benefit the patient, with interdisciplinary cooperation ensuring optimal treatment.
Bernhard Rhein, Ph.D., and medical physicist at Heidelberg University Hospital, said, “The Monte Carlo dose engine has resulted in more accurate dose computation, especially for bone structures and the borders between tissues of differing densities. This is a significant step forward in bringing the calculated dose closer to the actual dose.”
For more information: www.raysearchlabs.com
November 13, 2025 
