Quantitative morphology of late renal radiation injury

Transcriptomics in cancer revealed by Positron Emission Tomography radiomics

Metabolic images from Positron Emission Tomography (PET) are used routinely for diagnosis, follow-up or treatment planning purposes of cancer patients. In this study we aimed at determining if radiomic features extracted from 18F-Fluoro Deoxy Glucose (FDG) PET images could mirror tumor transcriptomics. In this study we analyzed 45 patients with locally advanced head and neck cancer (H&N) that underwent FDG-PET scans at the time of diagnosis and transcriptome analysis using RNAs from both cancer and healthy tissues on microarrays. Association between PET radiomics and transcriptomics was carried out with the Genomica software and a functional annotation was used to associate PET radiomics, gene expression and altered biological pathways. We identified relationships between PET radiomics and genes involved in cell-cycle, disease, DNA repair, extracellular matrix organization, immune system, metabolism or signal transduction pathways, according to the Reactome classification. Our results suggest that these FDG PET radiomic features could be used to infer tissue gene expression and cellular pathway activity in H&N cancers. These observations strengthen the value of radiomics as a promising approach to personalize treatments through targeting tumor-specific molecular processes.

Morphologic effects of fast neutrons or photons on the canine kidney

Thirty-nine adult male Beagles received either fast neutron or photon irradiation to the right thorax to determine the relative biological effectiveness of fast neutrons on normal pulmonary tissue. The right anterior abdomen, including the cranial half of the right kidney, was included in the field of irradiation. Twenty-four dogs (six/group) received fast neutrons with an average energy of 15 MeV to total doses of 1000, 1500, 2250, or 3375 cGy in four fractions per week for 6 weeks. Fifteen dogs received 3000, 4500, or 6750 cGy of photons (five/group) in an identical fractionation pattern. All 12 neutron irradiated dogs receiving 3375 and 2250 cGy and 1 of 6 receiving 1500 cGy, developed clinical and clinical pathologic signs of hepatic, pancreatic, and gastrointestinal disturbances, but no signs of renal injury were seen. These 13 dogs died or were euthanatized 47-367 days after irradiation. Only 1 of 5 dogs receiving 6750 cGy of photons developed similar signs and died 708 days post-irradiation. The remaining 11 neutron irradiated dogs and 14 photon irradiated dogs eventually died of other causes. All 39 dogs were necropsied and their kidneys were compared to each other and to control dogs. Radiation induced lesions included hemorrhages, necrosis and disappearance of tubular epithelia, glomerulosclerosis, atrophy and fibrosis. These lesions were associated with degenerative and occlusive vascular changes and were much more severe in the neutron irradiated dogs. The relative biologic effectiveness of fast neutrons for canine kidney assessed by gross and microscopic pathology is approximately 4.5 (6750/1500).

Concomitant evaluation of efficiency, acute and delayed toxicities of combined treatment of radiation and CDDP on an in vivo model

The efficiency, acute and delayed toxicities of different radio-chemotherapeutic combinations were assessed on an in vivo model (Krebs II ascitic carcinoma grafted to female Swiss mice). Mice were given whole abdomen irradiation (WAI) 2.5 to 10 Gy as a single dose (WAI). CDDP was given intraperitoneally at 0.5 to 4 mg/kg dose level, 12 hr before or after WAI. There was a relationship between dose of CDDP and increase of life span (ILS) of mice. However, WAI did not increase the life span. When a single dose of 2 mg/kg CDDP was given prior to a 2.5 Gy WAI, the ILS reached 47%. By contrast, it was only 37% when treatment sequence was reversed. When the WAI dose level was increased to 5 Gy, the ILS was not increased. The jejunal crypt cell number, determined 3 days after the last treatment, was not modified, regardless of the treatment sequence. There was no delayed renal toxicity. The study on the Krebs II ascites model confirms the tumor cell therapeutic potentiation without exacerbation of normal tissue damage.