Heart / Pericardium

Dose constraints

Whole Breast

Schedule	Constraint	Source
40.05 Gy / 15 fx or 42.56 Gy / 16 fx	V20 Gy <5%	RTOG 1005
	Mean <4 Gy	RTOG 1005
26 Gy / 5 fx FAST-Forward	V1.5 Gy <30%	FAST-Forward
	V7 Gy <5%	FAST-Forward

Keep mean dose as low as reasonably achievable; <2 Gy is often achievable. Consider breath hold.

Quoted from eviQ 3650, checked 2026-09-23. Full table with references →

Partial Breast

Schedule	Constraint	Source
All schedules 40.05 Gy/15 fx · 30 Gy/5 fx · 26 Gy/5 fx	Left-sided: mean ≤1.5 Gy (ideal), ≤2 Gy (acceptable)	ASTRO PBI 2023
	Right-sided: mean <0.7 Gy (ideal), <1 Gy (acceptable)	ASTRO PBI 2023

Volume goals also apply and differ by side.

Quoted from eviQ 3658, checked 2026-09-23. Full table with references →

Post-Mastectomy Chest Wall

Schedule	Constraint	Source
50 Gy / 25 fx	V20 Gy <5%	RTOG 1005
	Mean <4 Gy	RTOG 1005
26 Gy / 5 fx FAST-Forward	V1.5 Gy <30%	FAST-Forward
	V7 Gy <5%	FAST-Forward

Keep mean dose as low as reasonably achievable; <2 Gy is often achievable. Consider breath hold.

Quoted from eviQ 1925, checked 2026-09-23. Full table with references →

Regional Nodal Irradiation

Schedule	Constraint	Source
45–50 Gy / 25 fx 1.8–2 Gy per fraction	V25 Gy <10%	QUANTEC heart
	Mean <5 Gy	eviQ 1924
40 Gy / 15 fx	V17 Gy <10%	eviQ 1924

Mean <5 Gy may be hard to achieve; keep as low as reasonably achievable. Consider breath hold.

Quoted from eviQ 1924, checked 2026-09-23. Full table with references →

Anatomy

The heart lies in the middle mediastinum inside the pericardial sac, with its base superiorly where the great vessels enter and leave and its apex pointing anteriorly, inferiorly and to the left. Its superior boundary on CT is the part most often defined differently between atlases.

Function in the body

The heart pumps blood through the lungs and around the body.

Why it matters

SBRT: most relevant for tumors next to the heart or pericardium; toxicity endpoints in SBRT tables include pericarditis.
Conventional lung RT: cardiac dose has received growing attention in locally advanced lung cancer. Secondary analyses of RTOG 0617 are a good entry point to that literature.
Esophagus and upper GI: the heart sits directly in front of the lower esophagus and gastroesophageal junction, so mid and distal esophageal plans are often limited by heart dose. Liver SBRT near the dome of the liver can also bring the heart close to high dose.
Breast: the heart sits directly behind the left breast and chest wall, and Darby 2013 linked mean heart dose to later coronary events — which is why breast protocols ask for heart dose as low as reasonably achievable and suggest considering breath-hold techniques. Internal mammary nodal treatment can increase heart dose further. Breast protocols increasingly limit the LAD as well, because mean heart dose can stay low while the LAD receives much more.

Because the heart is a large organ, both point-dose and volume-based metrics (such as mean dose or a Vx) appear in published sources, depending on the fractionation and the endpoint.

How to contour

Feng 2011, a cardiac CT atlas built with cardiology and cardiac radiology:

Top: the heart starts just below the left pulmonary artery. For simplicity, a rounded contour that also takes in the great vessels can be drawn there.
Bottom: the heart blends with the diaphragm.
Include the fatty tissue inside the pericardium, because the coronary vessels run in it, even where no heart muscle is visible.
The superior vena cava can be contoured separately on a contrast scan; on a non-contrast scan it can be included for consistency.
A window level of 50 and width of 500 shows most structures.

Timmerman 2022 (Tables 8–11, written for its SBRT dose tables) contours the heart with the pericardial sac, starting at the bottom of the aortic arch (the aortopulmonary window) and ending at the heart's apex. The two sources set the top of the heart at different levels, so match the source behind your limit.

Contouring atlasUnder Review

Development and validation of a heart atlas to study cardiac exposure to radiation following treatment for breast cancer

Feng M, Moran JM, Koelling T, et al. · 2011

Atlas for contouring the heart and its substructures, including the coronary arteries, developed and validated for studying cardiac dose in breast radiotherapy.

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Review articleSource Verified

A Story of Hypofractionation and the Table on the Wall

Timmerman R · UT Southwestern Medical Center · 2022

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.

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