Radiotherapy of abdomen with precise renal assessment with SPECT/CT imaging (RAPRASI): design and methodology of a prospective trial to improve the understanding of kidney radiation dose response.
BACKGROUND
The kidneys are a principal dose-limiting organ in radiotherapy for upper abdominal cancers. The current understanding of kidney radiation dose response is rudimentary. More precise dose-volume response models that allow direct correlation of delivered radiation dose with spatio-temporal changes in kidney function may improve radiotherapy treatment planning for upper-abdominal tumours.


METHODS
The Radiotherapy of Abdomen with Precise Renal Assessment with SPECT/CT Imaging (RAPRASI) is an observational clinical research study with participating sites at Sir Charles Gairdner Hospital (SCGH) in Perth, Australia and the Peter MacCallum Cancer Centre (PMCC) in Melbourne, Australia. Eligible patients are those with upper gastrointestinal cancer, without metastatic disease, undergoing conformal radiotherapy that will involve incidental radiation to one or both kidneys. For each patient, total kidney function is being assessed before commencement of radiotherapy treatment and then at 4, 12, 26, 52 and 78 weeks after the first radiotherapy fraction, using two procedures: a Glomerular Filtration Rate (GFR) measurement using the 51Cr-ethylenediamine tetra-acetic acid (EDTA) clearance; and a regional kidney perfusion measurement assessing renal uptake of 99mTc-dimercaptosuccinic acid (DMSA), imaged with a Single Photon Emission Computed Tomography / Computed Tomography (SPECT/CT) system. The CT component of the SPECT/CT provides the anatomical reference of the kidney's position. The data is intended to reveal changes in regional kidney function over the study period after the radiotherapy. These SPECT/CT scans, co-registered with the radiotherapy treatment plan, will provide spatial correlation between the radiation dose and regional renal function as assessed by SPECT/CT. From this correlation, renal response patterns will likely be identified with the purpose of developing a predictive model.


BACKGROUND
Australian New Zealand Clinical Trials Registry: ACTRN12609000322235.
Juanita
J
Lopez-Gaitan
Martin A
MA
Ebert
Peter
P
Robins
Jan
J
Boucek
Trevor
T
Leong
David
D
Willis
Sean
S
Bydder
Peter
P
Podias
Gemma
G
Waters
Brenton
B
O'Mara
Julie
J
Chu
Jessica
J
Faggian
Luke
L
Williams
Michael S
MS
Hofman
Nigel A
NA
Spry
D000008:Abdominal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy*; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000503:physiopathology* / Q000528:radiation effects; D007677:Kidney Function Tests; D009520:New Zealand; D011379:Prognosis; D011446:Prospective Studies; D020266:Radiotherapy, Conformal; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*