ESTRO ACROP: Technology for precision small animal radiotherapy research: Optimal use and challenges

Abstract

Many radiotherapy research centers have recently installed novel research platforms enabling the investigation of the radiation response of tumors and normal tissues in small animal models, possibly in combination with other treatment modalities. Many more research institutes are expected to follow in the coming years. These novel platforms are capable of mimicking human radiotherapy more closely than older technology. To facilitate the optimal use of these novel integrated precision irradiators and various small animal imaging devices, and to maximize the impact of the associated research, the ESTRO committee on coordinating guidelines ACROP (Advisory Committee in Radiation Oncology Practice) has commissioned a report to review the state of the art of the technology used in this new field of research, and to issue recommendations. This report discusses the combination of precision irradiation systems, small animal imaging (CT, MRI, PET, SPECT, bioluminescence) systems, image registration, treatment planning, and data processing. It also provides guidelines for reporting on studies.

A failure modes and effects analysis quality management framework for image‐guided small animal irradiators: A change in paradigm for radiation biology

“…1,[38][39][40] Recently published guidelines by ESTRO-ACROP provide detailed description of the current technological status of these units, as well as recommendations as to their operation, developing workflow, and which aspects should be commissioned before use. 17 Both commercially available systems are similar but have some subtle differences. The Xstrahl SARRP acquires CBCT images using a stationary x-ray tube and detector while rotating the couch 360°, whereas the PXi XRAD-SmART acquires CBCT images using a more traditional geometry where the source and detector rotate 360°around the stationary couch.…”

“…However, despite the rapid influx of new technology, comprehensive quality assurance (QA) protocols similar to the AAPM TG-142 5 for linear accelerator are still virtually nonexistent, and radiation biology study protocols present wide variations from site to site. [6][7][8][9][10] Many attempts have been made to produce rigorous systematic and prescriptive QA [11][12][13][14][15][16][17] methodologies similar to those employed in the clinic for patient radiation therapy (RT) such as the AAPM Task Group 40 18 and 142. 5 These approaches typically focus on comprehensive dosimetry and geometrical tests performed by physics specialists with knowledge and access to specialized equipment such as special dosimetric phantoms, 16,19 GAFChromic EBT film, 15,20 alanine detectors, 21 and ionization chamber measurements.…”

Online dose delivery verification in small animal image‐guided radiotherapy

“…To accomplish novel radiation treatment techniques in preclinical radiation research, small animal image-guided radiotherapy (SA-IGRT) systems have been increasingly integrated into preclinical radiation research over the last decade. [4][5][6] Although such systems have sophisticated tools (such as cone-beam computed tomography [CBCT]-based volumetric image guidance, robotic couch, three-dimensional [3D] treatment planning, and electronic portal imaging devices [EPIDs]), to our knowledge, no established technique can perform independent, online verification of the delivered dose distribution for each beam. Development of such dose verification techniques would allow users to quantify deviations of the delivered dose from the intended plan, and potentially enable the user to perform corrections over remaining fractions.…”

Kilovoltage transit and exit dosimetry for a small animal image‐guided radiotherapy system using built‐in EPID

“…These systems enable close emulation of the clinical radiotherapy environment and process. Commercial SA‐IGRT systems currently provide users with high‐resolution cone‐beam computed tomography (CBCT), inverse treatment planning for 3D dose calculations, respiratory gating, and bioluminescent optical imaging modalities …”

“…Commercial SA-IGRT systems currently provide users with high-resolution cone-beam computed tomography (CBCT), inverse treatment planning for 3D dose calculations, respiratory gating, and bioluminescent optical imaging modalities. [1][2][3] The accuracy of dose delivery in the SA-IGRT systems depends on a number of operator-and system-related factors that can individually or cumulatively contribute to significant dosimetric errors. Possible sources of error include incorrect filter selection, gantry sag and wobble, couch rotation, and collimator misalignment.…”