Additive manufacturing in radiation oncology:a review of clinical practice,emerging trends and research opportunities

The additive manufacturing(AM)process plays an important role in enabling cross-disciplinary research in engineering and personalised medicine.Commercially available clinical tools currently utilised in radiotherapy are typically based on traditional manufacturing processes,often leading to non-conformal geometries,time-consuming manufacturing process and high costs.An emerging application explores the design and development of patient-specific clinical tools using AM to optimise treatment outcomes among cancer patients receiving radiation therapy.In this review,we:•highlight the key advantages of AM in radiotherapy where rapid prototyping allows for patient-specific manufacture•explore common clinical workflows involving radiotherapy tools such as bolus,compensators,anthropomorphic phantoms,immobilisers,and brachytherapy moulds;and•investigate how current AM processes are exploited by researchers to achieve patient tissuelike imaging and dose attenuations.Finally,significant AM research opportunities in this space are highlighted for their future advancements in radiotherapy for diagnostic and clinical research applications.

Recent advances in photonic dosimeters for medical radiation therapy

Radiation therapy,which uses X-rays to destroy or injure cancer cells,has become one of the most important modalities to treat the primary cancer or advanced cancer.High resolution,water equivalent and passive X-ray dosimeters are highly desirable for developing quality assurance（QA）systems for novel cancer therapy like microbeam radiation therapy（MRT）which is currently under development.Here we present the latest developments of high spatial resolution scintillator based photonic dosimeters,and their applications to clinical external radiation beam therapies：specifically high energy linear accelerator（LINAC）photon beams and low energy synchrotron photon beams.We have developed optical fiber dosimeters with spatial resolutions ranging from 50 to 500 gm and tested them with LINAC beams and synchrotron microbeams.For LINAC beams,the fiberoptic probes were exposed to a 6 MV,10 cm by 10 cm X-ray field and,the beam profiles as well as the depth dose profiles were measured at a source-to-surface distance（SSD）of 100 cm.We have also demonstrated the possibility for temporally separating Cherenkov light from the pulsed LINAC scintillation signals.Using the 50 μm fiber probes,we have successfully resolved the microstructures of the microbeams generated by the imaging and medical beamline（IMBL）at the Australian Synchrotron and measured the peak-to-valley dose ratios（PVDRs）.In this paper,we summarize the results we have achieved so far,and discuss the possible solutions to the issues and challenges we have faced,also highlight the future work to further enhance the performances of the photonic dosimeters.

基于阵列波导光栅的边缘滤波温度解调系统

为克服传统阵列波导光栅解调系统体积大、价格昂贵等问题,提出了以窄带光源为输入光源,采用边缘滤波和阵列波导光栅相结合的解调方案,实现对增敏封装后的光纤光栅温度传感器进行温度解调实验。以窄带光源作为输入,通过边缘滤波的方法使得温度传感器反射谱的中心波长偏移程度与解调光路输出光强的变化相对应,利用阵列波导光栅的波分复用实现多传感器同时测量,实现了多传感器多通道的分布式测量,实验结果表明:解调系统的波长解调范围为1545.30 nm~1560.50 nm,对35℃~42℃的温度范围进行检测,波长解调精度为±5.34 pm,温度测量误差可达±0.1℃。