Normal tissue side effects remain a major concern in radiotherapy. The improved precision of radiation dose delivery of recent technological developments in radiotherapy has the potential to reduce the radiation dose to organ regions that contribute the most to the development of side effects. This review discusses the contribution of regional variation in radiation responses in several organs. In the brain, various regions were found to contribute to radiation-induced neurocognitive dysfunction. In the parotid gland, the region containing the major ducts was found to be critical in hyposalivation. The heart and lung were each found to exhibit regional responses while also mutually affecting each other’s response to radiation. Sub-structures critical for the development of side effects were identified in the pancreas and bladder. The presence of these regional responses is based on a non-uniform distribution of target cells or sub-structures critical for organ function. These characteristics are common to most organs in the body and we therefore hypothesize that regional responses in radiation-induced normal tissue damage may be a shared occurrence. Further investigations will offer new opportunities to reduce normal tissue side effects of radiotherapy using modern and high-precision technologies.
Last. Gozde Yazici(Hacettepe University)H-Index: 11
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Background Our aim was to evaluate the correlation between the radiation doses to parotid gland (PG) stem cells and xerostomia. Methods Patients diagnosed with head and neck cancer (HNC) were retrospectively evaluated, and xerostomia inventory (XI) was applied to these patients. PG stem cells were delineated on the treatment planning CT, and the mean doses to the PG stem cells calculated. Results The total test score and mean doses to bilateral PGs were significantly correlated (r = .34, P = .00...
#1Eugenia Mylona(French Institute of Health and Medical Research)H-Index: 4
#2Martin A. Ebert(UWA: University of Western Australia)H-Index: 26
Last. Renaud de Crevoisier(French Institute of Health and Medical Research)H-Index: 28
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Abstract Purpose /Objectives: Recent voxel-based studies have shown that the dose to specific rectal and urethro-vesical subregions is predictive of toxicities, following prostate cancer IMRT. The objective of this study was to validate the discriminatory power of these subregions with respect to the whole organs, in a large independent population. Material/Methods The validation cohort consisted of 450 patients, from the XXX(BLIND) trial, treated with 3D-CRT at 66-74 Gy. Previous voxel-based an...
BACKGROUND: Hippocampus is considered to be the seat for neurocognitive functions. Avoidance of hippocampus during radiotherapy to brain may serve to preserve various domains of neurocognition. We aimed to derive radiotherapy dose constraints to hippocampi for preserving neurocognition in young patients with brain tumors by measuring various neurocognitive parameters. METHODS: Forty-eight patients with residual/progressive benign or low-grade brain tumors treated with stereotactic conformal radi...
Despite the dramatic advancements in pelvic radiotherapy, urinary toxicity remains a significant side-effect. The assessment of clinico-dosimetric predictors of radiation cystitis (RC) based on clinical data has improved substantially over the last decade; however, a thorough understanding of the physiopathogenetic mechanisms underlying the onset of RC, with its variegated acute and late urinary symptoms, is still largely lacking, and data from pre-clinical research is still limited. The aim of ...
Abstract Background and purpose Radiation-induced cardiac toxicity (RICT) remains one of the most critical dose limiting constraints in radiotherapy. Recent studies have shown higher doses to the base of the heart are associated with worse overall survival in lung cancer patients receiving radiotherapy. This work aimed to investigate the impact of sub-volume heart irradiation in a mouse model using small animal image-guided radiotherapy. Materials and Methods C57BL/6 mice were irradiated with a ...
Last. Markus Alber(University Hospital Heidelberg)H-Index: 32
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PURPOSE: Late radiation-induced contrast enhancing brain lesions (CEBL) on magnetic resonance (MR) images after proton therapy of brain tumors have been observed to occur frequently in regions of high linear energy transfer (LET) and in proximity to the ventricular system. We analyzed 110 low-grade glioma patients treated with proton therapy to determine if the risk for CEBLs is increased in proximity to the ventricular system and if there is a relationship between relative biological effectiven...
Background In treating glioblastoma, irradiation of the neural progenitor cell (NPC) niches is controversial. Lower hippocampal doses may limit neurocognitive toxicity, but higher doses to the subventricular zones (SVZ) may improve survival. Objective To prospectively evaluate the impact of limiting radiation dose to the NPC niches on tumor progression, survival, and cognition in patients with glioblastoma. Methods Patients with glioblastoma received resection followed by standard chemoradiation...
INTRODUCTION For lung cancer patients treated with radiotherapy, dose to the heart is associated with excess mortality. However, it is often not feasible to spare the whole heart. Therefore, our aim is to define cardiac sub-structure(s) and dose thresholds which optimally reduce early mortality. METHOD 14 cardiac sub-structures were delineated on 5 template patients with representative anatomies. 1,161 non-small cell lung cancer patients were non-rigidly registered to these 5 template anatomies,...
BACKGROUND: Childhood cancer survivors exposed to abdominal radiation (abdRT) are at increased risk for diabetes mellitus but the association between risk and radiation dose and volume is unclear. METHODS: Participants included 20,762 five-year survivors of childhood cancer (4,568 exposed to abdRT) and 4,853 siblings. For abdRT, we estimated maximum dose to abdomen, mean doses for whole pancreas, pancreatic head, body, tail, and percent pancreas volume receiving ≥10, ≥20, and ≥30Gy. Relative ris...
Abstract Background and purpose Proton radiotherapy offers the potential to reduce normal tissue toxicity. However, clinical safety margins, range uncertainties, and varying relative biological effectiveness (RBE) may result in a critical dose in tumor-surrounding normal tissue. To assess potential adverse effects in preclinical studies, image-guided proton mouse brain irradiation and analysis of DNA damage repair was established. Material and methods We designed and characterized a setup to sha...
This study investigates the dose–response patterns associated with radiation pneumonitis (RP) in patients treated for thoracic malignancies with different radiation modalities. To this end, voxel-based analysis (VBA) empowered by a novel strategy for the characterization of spatial properties of dose maps was applied. Data from 382 lung cancer and mediastinal lymphoma patients from three institutions treated with different radiation therapy (RT) techniques were analyzed. Each planning CT and bio...
For decades, dose-volume information for segmented anatomy has provided the essential data for correlating radiotherapy dosimetry with treatment-induced complications. Dose-volume information has formed the basis for modelling those associations via normal tissue complication (NTCP) models and for driving treatment planning. Limitations to this approach have been identified. Many studies have emerged demonstrating that the incorporation of information describing the spatial nature of the dose di...
NeoB is a radiotracer targeting the gastrin-releasing peptide receptor (GRPR), a G-protein–coupled receptor expressed in various cancers. The aim of the present study was to evaluate the biodistribution and efficacy of this new therapeutic agent in Gastrointestinal Stromal Tumors (GIST). Eighty-two SCID mice bearing GIST-882 tumors were employed. [177Lu]Lu-NeoB biodistribution was evaluated up to seven days by organ sampling (200 pmol/0.8 MBq, i.v.). For efficacy evaluation, mice received either...
