Evaluation of clinically applied treatment beams with respect to bunker shielding parameters for a Cyberknife M6.

Henzen, Dominik; Schmidhalter, Daniel; Zanella, Claudia Christina; Volken, Werner; Mackeprang, Paul-Henry; Malthaner, Marco; Fix, Michael; Manser, Peter (2018). Evaluation of clinically applied treatment beams with respect to bunker shielding parameters for a Cyberknife M6. Journal of applied clinical medical physics, 19(1), pp. 243-249. American Association of Physicists in Medicine 10.1002/acm2.12215

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Compared to a conventional linear accelerator, the Cyberknife (CK) is a unique system with respect to radiation protection shielding and the variety and number of non-coplanar beams are two key components regarding this aspect. In this work, a framework to assess the direction distribution and modulation factor (MF) of clinically applied treatment beams of a CyberKnife M6 is developed. Database filtering options allow studying the influence of different parameters such as collimator types, treatment sites or different bunker sizes. A distribution of monitor units (MU) is generated by projecting treatment beams onto the walls, floor and ceiling of the CyberKnife bunker. This distribution is found to be highly heterogeneous and depending, among other parameters, on the bunker size. For our bunker design, 10%-13% of the MUs are delivered to the right and left wall, each. The floor receives more than 64% of the applied MUs, while the wall behind the patient's head is not hit by primary treatment beams. Between 0% and 5% of the total MUs are delivered to the wall at the patient's feet. This number highly depends on the treatment site, e.g., for extracranial patients no beams hit that wall. Collimator choice was found to have minor influence on the distribution of MUs. On the other hand, the MF depends on the collimator type as well as on the treatment site. The MFs (delivered MU/prescribed dose) for all treatments, all MLC treatments, cranial and extracranial treatments are 8.3, 6.4, 7.7, and 9.9 MU/cGy, respectively. The developed framework allows assessing and monitoring important parameters regarding radiation protection of a CK-M6 using the actually applied treatment beams. Furthermore, it enables evaluating different clinical and constructional situations using the filtering options.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology > Medical Radiation Physics
04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology

UniBE Contributor:

Henzen, Dominik; Schmidhalter, Daniel; Volken, Werner; Mackeprang, Paul-Henry; Malthaner, Marco; Fix, Michael and Manser, Peter

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1526-9914

Publisher:

American Association of Physicists in Medicine

Language:

English

Submitter:

Beatrice Scheidegger

Date Deposited:

09 Apr 2018 11:56

Last Modified:

10 Apr 2018 06:32

Publisher DOI:

10.1002/acm2.12215

PubMed ID:

29125234

Uncontrolled Keywords:

SBRT Cyberknife radiation protection

BORIS DOI:

10.7892/boris.107684

URI:

https://boris.unibe.ch/id/eprint/107684

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