Radiation nephropathy is renal injury and loss of function caused by ionizing radiation.

1. Radiation Nephropathy
By: A.Haghbin

2. kidneys
 responsible for producing erythropoietin to stimulate red blood cell
production
filtering waste metabolites and electrolytes from the blood
modulating blood pressure by fluid/electrolyte balance

3. Radiation Nephropathy
Radiation nephropathy is renal injury and loss of function caused by
ionizing radiation.
Radiation nephropathy occurs as a late phenomenon, usually presenting
months to years after the radiation exposure.
Normal renal tissue has lowmitotic rates, which correlate with delayed
expression of renal injury after radiation

4. CLINICAL PRESENTATION
The clinical features of radiation nephropathy will vary according to
dose and volume of irradiation.
Acute radiation nephritis
Chronic radiation nephritis

5. Acute radiation nephritis
Most commonly occurs 6-12 months after exposure.
Signs and symptoms:
Malignant Hypertension, degrees of edema, proteinuria, severe anemia
disproportionate( microangiopathic hemolytic anemia), thrombocytopenia,
azotemia
Patients surviving this acute phase usually are left with progression to
CKD.

6. Chronic radiation nephritis
Most commonly occurs ≥18 months after exposure.
There are two variants of chronic nephritis:
-Primary chronic radiation nephritis
-secondary chronic radiation nephritis
Signs and symptoms:
hypertension, albuminuria, anemia, azotemia, small atrophic kidneys

7. Histopathology
Early changes include:
endothelialmicrovascular injury with cell swelling, subendothelial
expansion, capillary loop occlusion, mesangiolysis and variable
tubular injury
Late changes include:
sclerosis of interlobular and arcuate arteries, residual parenchymal
damage, increased mesangial matrix, glomerular scarring, tubular
atrophy, and renal mass reduction.

8. Arteriolonephrosclerosis, glomerular tufts of/erent arterioles rapid endothelial
swelling and proliferation, slower thickening walls arte./vein hypertension

9. Functional subunit
The FSU is the minimum unit that can function independently of the
remaining organ.
Thus, the observed global sensitivity of an organ will depend on the
inherent sensitivity of the target cells, as well as the number of target
cells within a FSU.
In the kidney:
nephron has a proximal tubule, loop of Henle, the distal tubule that are
dependent on each other.

10. Organizational structure between FSUs
A related consideration is the manner in which FSUs are ‘connected
to each other’ to yield the overall organ function
Normal organs can be broadly classified :
- parallel architecture
- series architecture
Kidney is parallel organ.

11. Distribution of Function
Organs can be considered to have homogeneous versus heterogeneous
function throughout.
Association between concepts of parallel versus series and
heterogeneous versus homogeneous function

12. Endpoint Assessment
Laboratory Findings:
CBC(microangiopathic hemolytic anemia ,Thrombocytopenia,..),
urinalysis , creatinine , glomerular filtration rate (GFR)or CrCl , blood
urea nitrogen (BUN).
 Radiological findings :
ultrasound , CT , MRI , SPECT/CT, 99mTC dimercaptosuccinyl acid
renography

13. Tolerance dose effect
ReferenceWhole or
partial organ
TD5/50TD5/5InjuryClass I organs
Kraut et al.,
Tefft
Kunkler et al
Whole (strip)
Whole
2000
2500
1500
2000
Acute and
chronic
nephrosclerosis
kidney
 Class I— Organs in which radiation lesions are fatal or result in severe morbidity

14. Parameters of therapy: tolerance doses
(TD5/5–TD50/5)
Fractionated
dose (Gy)
Single dose (Gy)
20-3010-20
 Dose-limiting organs and tissues in radiation oncology have been
defined according to their tolerance dose
Dose range (Gy)
TD5/5–TD50/5
Complication end pointTarget cell
23-28ArterionephrosclerosisKidney-glomeruli

15. QUANTEC Summary:
Notes on
dose/volume
parameter
Rate(%)Dose(Gy),
dose/volume
parameters
EndpointIrradiation
type
Volume
segmented
kidney
< 5Mean
dose<15-18
Clinically
relevant renal
dysfunction
Bilateral
whole oragan
or 3D-CRT
Bilateral
whole
<50Mean dose<28Clinically
relevant renal
dysfunction
Bilateral
whole oragan
Bilateral
whole
For combined
kidney
< 5V12< 55%
V20< 32%
V23< 30%
V28< 20%
Clinically
relevant renal
dysfunction
3D-CRTBilateral
whole

16. Reference
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