Intensity‐modulated radiation therapy dose prescription and reporting: Sum and substance of the International Commission on Radiation Units and Measurements Report 83 for veterinary medicine

Abstract

Institutions' adherence to protocol, quality assurance, and radiation parameter reporting are key to adequately interpret and compare treatment outcomes in radiation oncology. In 2017, the editorial board for Veterinary Radiology & Ultrasound adapted author guidelines on "technical information for radiation therapy (RT)". These guidelines provide a framework to report the RT treatment process in manuscripts resulting from veterinary clinical trials. In spite of this framework, however, in implementing IMRT, we have identified different "interpretations" of the extended prescription and reporting recommendations of the International Commission on Radiation Units and Measurements (ICRU 83), even within our small team. In the following commentary review, we provide a short summary of various detailed aspects of the ICRU 83 recommended (IMRT) prescription and reporting, including (a) absorbed target dose specification and prescription, (b) homogeneity and conformity, and (c) reporting of absorbed dose in organs at risk. In particular, we want to share our thoughts on possible dangers of noncompliance in adhering to protocol, prescription, and reporting. As veterinary IMRT publications still sparsely adhere to the recommendations of the ICRU, we were motivated to summarize the recommendations to facilitate appropriate reporting for IMRT in future veterinary studies. K E Y W O R D SIMRT, normalization, treatment planning, veterinary

Outcome comparison between radiation therapy and surgery as primary treatment for dogs with periarticular histiocytic sarcoma: An Italian Society of Veterinary Oncology study

“…Positioning and verification thereof were accomplished according to the individual institutions' routines. In all five 3DCRT‐plans, the recommendations for specifying dose and volumes were adhered to as proposed by Keyerleber et al (2012), and in the ICRU reports 50 and 62 and for the seven IMRT plans, recommendations of for 3DCRT and ICRU report 83 and Rohrer Bley et al (2019) were followed 11‐15 . The remaining 20 plans were hand‐calculated.…”

“…In the future, we recommend that treatment planners adhere to strict contouring and prescription guidelines. These include dose prescription and normalization, as well as standardized CTV delineation and PTV extension according to the institute's technical capabilities 14,15 . Most studies, including ours, are limited by a lack of standardized follow‐up imaging to assess tumour status.…”

Reducing margins for abdominopelvic tumours in dogs: Impact on dose‐coverage and normal tissue complication probability

“…Dose was optimized with IMRT using a dynamic 120 multi‐leaf collimator. Recommendations for specification of dose were adhered to as proposed by the International Commission on Radiation Units and Measurements (ICRU) report 83 and as recommended for veterinary medicine 9,19 . The dose was normalized adhering to the guidelines: the PTV D near‐min (the minimal dose‐coverage of D 98% ) was required with 95% of total prescribed dose (≥98% of the PTV was covered by the 95% isodose line) and D 50% (median dose) as the value of dose prescription.…”

“…The position is typically adjusted with a couch positional shift, and possible in four degrees of freedom ‐ longitudinal, vertical, horizontal, rotational (yaw) ‐ unless a 6D robotic couch is available allowing for additional pitch and roll corrections 8 . The consequential increase in precision often permits PTV reduction, which could result in lower toxicity and a shift in therapeutic ratio 9,10 . Appropriate PTV margins have not yet been established for IG‐IMRT treatment of tumours in the dog's abdominopelvic region and herein we explore if our usual 5 mm margin can be reduced further.…”

Outcome of a dog undergoing definitive‐intent intensity‐modulated radiation therapy for an intranasal ganglioneuroma

“…Intensity‐modulated radiation therapy was administered for a total dose of 42 Gy, such that 95% of the PTV volume received at least 95% of the prescribed dose (Figure 3). 1 The dog received 4.2 Gy per fraction daily over 2 weeks on Monday to Friday basis. Intensity‐modulated radiation therapy plan consisted of a single isocenter placed in the PTV, nine‐field coplanar technique.…”