D0.03cc / Near-Max Dose

The template NRG Oncology gives investigators for writing the radiation section of a lung SBRT trial. Its imaging section allows PET/CT or MRI for structure definition, asks that the images be registered accurately to the planning scan (following AAPM TG-132 for deformable registration), notes that PET may be needed to separate tumor from atelectasis or fibrosis, and suggests an extra margin when a fused image is the primary image for the GTV. Its target and planning sections (5.2.4 and 5.2.6–5.2.8) define the plan-quality measures for lung SBRT trials: the prescription as the dose covering 95% of the PTV, a D99% requirement, R100% (prescription isodose volume ÷ PTV), R50% (50% prescription isodose volume ÷ PTV) and D2cm (maximum dose at 2 cm from the PTV in any direction, as a percentage of the prescription), with a table of allowable dose spillage by PTV volume. It describes a 20 mm PTV expansion structure used to control intermediate dose spillage, asks that dose above 105% of prescription be avoided outside the PTV, describes a deliberately heterogeneous dose with the hotspot in the central GTV, defines the maximum dose on a 0.03 cc volume, and ranks planning priorities when target coverage and organ limits conflict.

The NRG Oncology template for the radiation section of a brain radiosurgery trial. Its example text asks for CT slices of 1.25 mm or less, strongly encourages MRI (contrast T1 and a 3D gradient-echo sequence) for target delineation, recommends fusing FDG-PET/CT when available, and asks that the fusion be done by a medical physicist and reviewed by the attending physician. Its plan-evaluation section defines the conformity index (CI, or R100%) as the prescription isodose volume ÷ PTV volume, R50% as the 50% prescription isodose volume ÷ target volume ("R50% defines dose falloff outside the target"), a heterogeneity index D5% ÷ D95%, and coverage as the PTV volume receiving the prescription dose ÷ PTV volume, and notes that criteria such as the CI should account for target size and treatment technology.

An editorial history of the UT Southwestern SABR constraint tables — often called the “Timmerman tables” — covering how they were developed and revised, and their relationship to AAPM TG-101 and NRG/RTOG protocols. Tables 2–11 separate serial tissues (listed with a volume, a volume max and a max point dose) from parallel tissues (listed with a critical volume and a critical-volume dose max). In Tables 2–7 a footnote defines “point” as ≤0.035 cm³; Tables 8–11 add a contouring-instructions column for each structure.

UK consensus on dose–volume constraints for SABR of oligometastases, primary lung cancer and hepatocellular carcinoma. Citation checked against Crossref. DoseLab read the tables in the authors' accepted manuscript (UCL Discovery and White Rose Research Online): Table 6 (intracranial, 1, 3 and 5 fractions) for the brain pages, and Tables 2, 3 and 5 (thoracic, abdominal and spinal) for the liver SBRT page. Each table gives optimal and mandatory limits by fraction count; the liver limits apply to patients with, at worst, Child-Pugh A6 liver disease. The kidney limit is written as a "cold" constraint — at least 200 cc must receive no more than the stated dose.

Recommendations for standardized naming of targets, organs at risk and dose-volume metrics. Section 9 sets out the DVH-metric nomenclature DoseLab follows: Vx (volume receiving at least dose x), Dx (minimum dose to the hottest sub-volume x), CVx and DCx (the "cold" complements), output units in square brackets (Gy or % of prescription; cc or % of the structure), and an EQD2Gy unit with the α/β written in parentheses — for example D90%(10)[EQD2Gy]. Section 10 asks that DVH metrics say whether a lower-dose PTV is segmented (excludes the higher-dose PTV) or not. Read in the AAPM report PDF.

ICRU report on prescribing, recording and reporting intensity-modulated photon therapy. DoseLab has not read the report itself (it is sold by the ICRU). Its homogeneity index, (D2% − D98%) / D50%, is checked as quoted in the open-access Yan 2019 paper.

Proposes a new homogeneity index. Its introduction lists the indices in use — Dmax/Dp, D5/D95, (D2 − D98)/Dp and the ICRU Report 83 version (D2 − D98)/D50 — notes that lower values of the last two mean a more homogeneous dose, and that each is based on only two or three points of the DVH. Full text read in Europe PMC (PMC6839365).