ESTRO 2023 - Abstract Book

S1959

Digital Posters

ESTRO 2023

TG-43 Dw may now be calculated faster and accurately in RapidBrachyMCTPS in lieu of MC simulations. Further benchmarking of TG-43 dose calculations in RapidBrachyMCTPS will be completed with different sites and will be validated against dose calculations from clinical TPS.

PO-2174 Implementation of new safety and security measures for a brachytherapy treatment room

M. Baumgartl 1 , R. Buchegger 2 , M. Guckenberger 1 , S. Tanadini-Lang 1

1 University Hospital Zurich, Department of Radiation Oncology, Zurich, Switzerland; 2 University Hospital Zurich, Department of Security - Property and Personal Protection, Zurich, Switzerland Purpose or Objective Since a revision of the radiological protection ordinance , a higher standard on safety and security (S&S) for high-activity sealed radioactive sources (HASS) is requested and has to be implemented by all license holders working with such sources. In our institution a brachytherapy programme was established that provides high dose rate treatment with a HASS. Hence, S&S measures had to be re-assessed and adapted. One year of experience with a new S&S standard will be shared without discussing detailed confidential information of our S&S infrastructure itself. Materials and Methods In order to apply all the requested measures we assessed the situation and prepared a confidential, site-specific security plan in close cooperation with our in-house security department and local authorities. Beside a high end security infrastructure, simple measures were applied with little effort and investment to increase S&S to such an extent that anyone with malicious intentions is discouraged from attempting any criminal action. The main components of our security plan are: 1)definition of the roles of the radiation protection officer and safety manager; 2)reconstruction of the room to enable safe storage of the source; 3)restriction of access to the source; 4)advanced training of all staff members; and 5)teaching of external partners. Results The radiation protection officer and safety manager roles for brachytherapy were assigned to experienced personnel to assess, implement and supervise the security plan. The technical infrastructure for the treatment room was adapted to meet national and international standards. Direct access to the treatment source was reduced to five persons with the highest security level. The rest of the HDR staff were given only limited clearance to the vault, according to their responsibilities. During the implementation process in total 12 teaching sessions for external (#4) and internal (#8) parties were hold to provide information tailored only for their purpose. This paved the way for continuous education in annual cycles. The understanding of possible threats and preparation for different scenarios was taught which justified the higher S&S standards. In total 12 incidents occurred, categorized in three types of minor incidents: out of protocol, technical and miscellaneous incidents. Out of protocol incidences which were due to human errors and were randomly distributed over the year.

Conclusion For one year, new measures have been implemented without any major incidents. The biggest challenge was to change the mind-sets of non-occupationally exposed groups and to increase the level of understanding among each contributor for a sustainable safety culture. Training session are essential and results in higher confidence among the staff. Hence, operating on a higher standard of S&S is possible with little limitation.

PO-2175 Estimation of dose of a brachytherapy source to train public authorities for an emergency situation

M. Baumgartl 1 , M. Ackermann 2 , K. Uher 1 , S. Tanadini-Lang 1

1 University Hospital Zurich, Department of Radiation Oncology, Zurich, Switzerland; 2 Stadtpolizei Zurich, Kommissariat Intervention, Zurich, Switzerland Purpose or Objective In HDR brachytherapy, a HASS at the shape of a pellet and the of a rice grain is used to treat interior/superficial target volumes. In Switzerland, with the revised radiological protection ordinance the public authorities have been starting to focus more on prevention, detection and intervention of HASS. The latest raised the question on personal exposure due to radiation from an abandoned/stolen clinical iridium-192 source. To teach public authorities for such a scenario, an estimation of the personal dose equivalent Hp (10) and surface dose Hs (0.07) to extremities at certain distances for a