Tomasz Horwacik

Practice Patterns Analysis of Ocular Proton Therapy Centers: The International OPTIC Survey.

PURPOSE To assess the planning, treatment, and follow-up strategies worldwide in dedicated proton therapy ocular programs. METHODS AND MATERIALS Ten centers from 7 countries completed a questionnaire survey with 109 queries on the eye treatment planning system (TPS), hardware/software equipment, image acquisition/registration, patient positioning, eye surveillance, beam delivery, quality assurance (QA), clinical management, and workflow. RESULTS Worldwide, 28,891 eye patients were treated with protons at the 10 centers as of the end of 2014. Most centers treated a vast number of ocular patients (1729 to 6369). Three centers treated fewer than 200 ocular patients. Most commonly, the centers treated uveal melanoma (UM) and other primary ocular malignancies, benign ocular tumors, conjunctival lesions, choroidal metastases, and retinoblastomas. The UM dose fractionation was generally within a standard range, whereas dosing for other ocular conditions was not standardized. The majority (80%) of centers used in common a specific ocular TPS. Variability existed in imaging registration, with magnetic resonance imaging (MRI) rarely being used in routine planning (20%). Increased patient to full-time equivalent ratios were observed by higher accruing centers (P=.0161). Generally, ophthalmologists followed up the post-radiation therapy patients, though in 40% of centers radiation oncologists also followed up the patients. Seven centers had a prospective outcomes database. All centers used a cyclotron to accelerate protons with dedicated horizontal beam lines only. QA checks (range, modulation) varied substantially across centers. CONCLUSIONS The first worldwide multi-institutional ophthalmic proton therapy survey of the clinical and technical approach shows areas of substantial overlap and areas of progress needed to achieve sustainable and systematic management. Future international efforts include research and development for imaging and planning software upgrades, increased use of MRI, development of clinical protocols, systematic patient-centered data acquisition, and publishing guidelines on QA, staffing, treatment, and follow-up parameters by dedicated ocular programs to ensure the highest level of care for ocular patients.

Ambient dose equivalent measurements in secondary radiation fields at proton therapy facility CCB IFJ PAN in Krakow using recombination chambers

Abstract This work presents recombination methods used for secondary radiation measurements at the Facility for Proton Radiotherapy of Eye Cancer at the Institute for Nuclear Physics, IFJ, in Krakow (Poland). The measurements of H*(10) were performed, with REM-2 tissue equivalent chamber in two halls of cyclotrons AIC-144 and Proteus C-235 and in the corridors close to treatment rooms. The measurements were completed by determination of gamma radiation component, using a hydrogen-free recombination chamber. The results were compared with the measurements using rem meter types FHT 762 (WENDI-II) and NM2 FHT 192 gamma probe and with stationary dosimetric system.

Radiation exposure at the proton eye therapy facility at IFJ in Kraków

The proton radiotherapy facility for the treatment of eye tumors is under development at the Institute of Nuclear Physics (IFJ) in Kraków. The optical line installed at the treatment room is applied to form and monitor the 60 MeV proton beam provided by the AIC-144 isochronous cyclotron. Typical proton dose rates measured at the isocentre varied between 0.01 and 0.5 Gy/s. The intensities of the secondary radiation field inside and around the treatment room have been measured with a stationary monitoring system. Four sets of radiation monitors provide the continuous monitoring of gamma and neutron radiation during the operation of the facility. Monte Carlo calculations have been performed for understanding the structure of the radiation field inside the treatment room. Typical ambient dose equivalent rates inside the treatment room vary between 100 and 800 μSv/h for neutrons and between 10 and 130 μSv/h for gamma rays. The maximum values were found to be 2.5 mSv/h and 0.3 mSv/h respectively. The ambient dose equivalent rates outside the therapy room were not higher than 2.5 μSv/h for neutrons and 0.35 μSv/h for gamma rays. The end of the beam line, the optical line and the beam scattering system are main sources of the secondary radiation. Optimisation and shielding of these elements will reduce the patient and facility personnel exposure to the secondary radiation.