Administering the correct dosages to fight cancerous tumors can be a difficult balancing act. Too much of the radioactive drugs can cause harm to healthy tissue, but not enough will see the cancer cells survive and continue to spread. But a new technique developed at The Institute of Cancer Research in London may afford doctors an unprecedented level of accuracy in performing radiotherapy, using 3D-printed replicas of a patient’s organs and tumors to better determine how much radiation a tumor has received.

In preparing for radiotherapy, using models of a tumor is not uncommon, but these are typically hand-made and aren’t always so reliable.

"The big challenge we faced was to produce a model that was both anatomically accurate and allowed us to monitor the dose of radiation it received," says Dr Jonathan Gear, Clinical Scientist at The Institute of Cancer Research. "We found that the printed replicas could give us information we couldn’t get from 2D scans, you will always get more information from a 3D model than a flat image."

Gear and his fellow researchers are physicists working in molecular radiotherapy, a method used in treating thyroid cancer, adult neuroendocrine tumors, childhood neuroblastoma and bone metastases from prostate cancer. Using scans taken during patient treatment, the team 3D printed replicas of a tumor and surrounding organs. Dubbed "phantoms," the plastic models were filled with the same radioactive liquid given to patients and then monitored to see the likely effects of radiotherapy in that particular patient.

The researchers say that in their initial testing, the method allowed them to more precisely calculate the dose of radiation received by the patient and then adjust the following treatments accordingly. While promising, the scientists say that further testing in larger studies is needed, but if successful, the technique could greatly improve the precision of molecular radiotherapy.

"We’ve seen reports on how 3D printing is being used for prosthetics and to inform surgery, and this research shows it has the potential to improve cancer treatment too, by helping us to perform complex radiotherapy calculations more accurately," says Dr Glenn Flux, Head of Radioisotope Physics at the Joint Department of Physics at The Institute of Cancer Research. "We’re really excited by this technology and the potential it has for personalizing cancer treatment with highly targeted radiation."

This ability to customize treatments extends well beyond cancer therapies. Earlier this year we saw a 3D printed replica of an baby’s defected heart help surgeons prepare for what would be a life-changing surgery. It has also allowed surgeons to develop customized medical implants, including everything from a titanium heel to an upper jaw prosthesis.