scholarly journals Radiobiological Evaluation of Combined Gamma Knife Radiosurgery and Hyperthermia for Pediatric Neuro-Oncology

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3277
Author(s):  
Morteza Ghaderi Aram ◽  
Massimiliano Zanoli ◽  
Håkan Nordström ◽  
Iuliana Toma-Dasu ◽  
Klas Blomgren ◽  
...  
Keyword(s):  
Brain Tumour ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Linear Quadratic ◽  
Temperature Dependent ◽  
Malignant Brain Tumour ◽  
Tumour Control ◽  
Tumour Control Probability ◽  
Quantitative Metrics ◽  
Wide Range

Combining radiotherapy (RT) with hyperthermia (HT) has been proven effective in the treatment of a wide range of tumours, but the combination of externally delivered, focused heat and stereotactic radiosurgery has never been investigated. We explore the potential of such treatment enhancement via radiobiological modelling, specifically via the linear-quadratic (LQ) model adapted to thermoradiotherapy through modulating the radiosensitivity of temperature-dependent parameters. We extend this well-established model by incorporating oxygenation effects. To illustrate the methodology, we present a clinically relevant application in pediatric oncology, which is novel in two ways. First, it deals with medulloblastoma, the most common malignant brain tumour in children, a type of brain tumour not previously reported in the literature of thermoradiotherapy studies. Second, it makes use of the Gamma Knife for the radiotherapy part, thereby being the first of its kind in this context. Quantitative metrics like the biologically effective dose (BED) and the tumour control probability (TCP) are used to assess the efficacy of the combined plan.

Tumour control probability of a UK cohort of lung SABR patients

2020 ◽  
pp. 1-3
Author(s):  
J. E. Marsden
Keyword(s):  
The Other ◽  
Stereotactic Ablative Radiotherapy ◽  
Linear Quadratic ◽  
Planning Techniques ◽  
Tumour Control ◽  
Tumour Control Probability ◽  
The Uk

Abstract Aims: The aim of this work is to report on the tumour control probability (TCP) of a UK cohort of lung stereotactic ablative radiotherapy patients (n = 198) for a range of dose and fractionations common in the UK. Materials and methods: TCP values for 3 (54 Gy), 5 (55 and 60 Gy) and 8 (50 Gy) fraction (#) schemes were calculated with the linear-quadratic Marsden TCP model using the Biosuite software. Results: TCP values of 100% were computed for the 3 # and for 5 # (α/β = 10 Gy) cohorts; reduced to 99% (range 97–100) for the 5 # cohort only when an α/β of 20 Gy was used. The average TCP value for the 50 Gy in 8 # regime was 97% (range 92–99, α/β = 10 Gy) and 64% (range 48–79, α/β = 20 Gy). Statistical significant differences were observed between the α/β of 10 Gy versus 20 Gy groups and between all data grouped by fraction. Conclusion: TCPs achievable with current planning techniques in the UK have been presented. The ultra-conservative 50 Gy in 8 # scheme returns a significantly lower TCP than the other regimes.

scholarly journals An in vivo genetic screen in Drosophila identifies the orthologue of human cancer/testis gene SPO11 among a network of targets to inhibit lethal(3)malignant brain tumour growth

Open Biology ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. 170156 ◽  
Author(s):  
Fabrizio Rossi ◽  
Cristina Molnar ◽  
Kazuya Hashiyama ◽  
Jan P. Heinen ◽  
Judit Pampalona ◽  
...  
Keyword(s):  
Brain Tumour ◽  
Target Genes ◽  
Human Cancer ◽  
Loss Of Function ◽  
Malignant Growth ◽  
Malignant Brain Tumour ◽  
Rnai Technology ◽  
Wide Range ◽  
Cancer Testis

Using transgenic RNAi technology, we have screened over 4000 genes to identify targets to inhibit malignant growth caused by the loss of function of lethal(3)malignant brain tumour in Drosophila in vivo . We have identified 131 targets, which belong to a wide range of gene ontologies. Most of these target genes are not significantly overexpressed in mbt tumours hence showing that, rather counterintuitively, tumour-linked overexpression is not a good predictor of functional requirement. Moreover, we have found that most of the genes upregulated in mbt tumours remain overexpressed in tumour-suppressed double-mutant conditions, hence revealing that most of the tumour transcriptome signature is not necessarily correlated with malignant growth. One of the identified target genes is meiotic W68 ( mei-W68 ), the Drosophila orthologue of the human cancer/testis gene Sporulation-specific protein 11 ( SPO11 ), the enzyme that catalyses the formation of meiotic double-strand breaks. We show that Drosophila mei-W68/SPO11 drives oncogenesis by causing DNA damage in a somatic tissue, hence providing the first instance in which a SPO11 orthologue is unequivocally shown to have a pro-tumoural role. Altogether, the results from this screen point to the possibility of investigating the function of human cancer relevant genes in a tractable experimental model organism like Drosophila.

scholarly journals Gamma Knife Radiosurgery: An Overview of Physics, Chemistry, Biology and Neuro-medicine

1970 ◽  
Vol 28 (2) ◽  
pp. 100-112
Author(s):  
KMN Uddin ◽  
JN Islam
Keyword(s):  
Gamma Knife ◽  
Vascular Malformations ◽  
Gamma Knife Radiosurgery ◽  
High Energy ◽  
Quadratic Model ◽  
High Dose ◽  
Linear Quadratic ◽  
Treatment Unit ◽  
Stereotactic Technique ◽  
Living Tissues

The gamma knife is a highly specialized treatment unit thatprovides an advanced sophisticated stereotactic approachto treatment of tumour and vascular malformations withinthe internal structure of the head. The gamma knife deliversa single high dose of radiation emanating from 201 cobalt-60 unit sources. All 201 beam simultaneously intersect atthe same time in a pre-defined location. The treatmentplanning system for gamma knife radiosurgery has beendeveloped using nonlinear programming techniques. Thesystem optimizes the shot sizes, location and weights forgamma knife treatments. Open stereotactic technique in the1990’s was essential for the treatment of a number offunctional conditions and cystic space occupying lesions.It has an important part to play in the investigation oftumours and can help to increase the number which areaccessible to treatment. It can be employed to guide notonly solid instruments but also ionizing irradiation to “masslesion– targets”. It is just this combination of stereotacticguidance and narrow beam, high energy radiation toprecisely defined target, is the basis of gamma kniferadiosurgery . The topic on radiological physics presents abroad field, which includes physics of radiation therapy,diagnosis and nuclear medicine. The emphasis is on thebasic physical principles which form a common foundationfor these areas. Consequently, the topic provides both basicradiation physics, physical aspects of treatment planningand use of radiation beams. Some knowledge of the effectof ionizing radiation on living tissues is necessary, for thosewho wish to understand the nature of any treatment usingradiation and who also wish to inform patients about suchtreatment. The topic relates to the effects of radiation onvisible structures, in other words, cells and tissues. Theradiobiological knowledge described here has beendeveloped in relation to standard radiotherapy. Moreover,the linear quadratic model of cell killing is also applicablefor single dose irradiation.DOI: 10.3329/jbcps.v28i2.5370J Bangladesh Coll Phys Surg 2010; 28: 100-112

scholarly journals Prostate cancer tumour control probability modelling for external beam radiotherapy based on multi-parametric MRI-GTV definition

2020 ◽  
Author(s):  
Ilias Sachpazidis ◽  
Panayiotis Mavroidis ◽  
Constantinos Zamboglou ◽  
Christina Marie Klein ◽  
Anca-Ligia Grosu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Logistic Model ◽  
Radiation Treatment ◽  
Prostate Gland ◽  
Biochemical Relapse ◽  
Linear Quadratic ◽  
Tumour Control ◽  
Tumour Control Probability ◽  
Multivariate Logistic Model

Abstract Purpose: To evaluate the applicability and estimate the radiobiological parameters of linear-quadratic Poisson tumour control probability (TCP) model for primary prostate cancer patients for two relevant target structures (prostate gland and GTV). The TCP describes the dose–response of prostate after definitive radiotherapy (RT). Also, to analyse and identify possible significant correlations between clinical and treatment factors such as planned dose to prostate gland, dose to GTV, volume of prostate and mpMRI-GTV based on multivariate logistic regression model.Methods: The study included 129 intermediate and high-risk prostate cancer patients (cN0 and cM0), who were treated with image-guided intensity modulated radiotherapy (IMRT) +/- androgen deprivation therapy with a median follow-up period of 81.4 months (range: 42.0 - 149.0) months. Tumour control was defined as biochemical relapse free survival according to the Phoenix definition (BRFS). MpMRI-GTV was delineated retrospectively based on a pre-treatment multi-parametric MR imaging (mpMRI), which was co-registered to the planning CT. The clinical treatment planning procedure was based on prostate gland, delineated on CT imaging modality. Furthermore, we also fitted the clinical data to TCP model for the two considered targets for the 5-year follow-up after radiation treatment, where our cohort was composed of a total number of 108 patients, of which 19 were biochemical relapse (BR) patients. Results: For the median follow-up period of 81.4 months (range: 42.0 - 149.0) months, our results indicated an appropriate α/β = 1.3 Gy for prostate gland and α/β = 2.9 Gy for mpMRI-GTV. Only for prostate gland, EQD2 and gEUD2Gy were significantly lower in the biochemical relapse (BR) group compared to the biochemical control (BC) group. Fitting results to the linear-quadratic Poisson TCP model for prostate gland and α/β = 1.3 Gy were D50 = 66.8 Gy with 95%CI [64.6 Gy, 69.0 Gy], and γ = 3.81 with 95%CI [2.58, 5.20]. For mpMRI-GTV and α/β = 2.9 Gy, D50 was 68.1 Gy with 95%CI [66.1 Gy, 70.0 Gy], and γ = 4.45 with 95%CI [3.00, 6.12]. The fitness of the model was better for prostate gland. For the multivariate logistic model, the gEUD2Gy for prostate gland showed a very high significant predictive value (p = 0.001), whereas regarding mpMRI-GTV only its volume showed a significance (p = 0.01). Finally, for the 5-year follow-up after the radiation treatment, our results for the prostate gland were: D50=64.6Gy [61.6Gy, 67.4Gy], γ=3.08 [2.03, 4.35], α/β=2.2Gy (95%CI was undefined). For the mpMRI-GTV, the optimizer was unable to deliver any reasonable results for the expected clinical D50 and α/β. The results for the mpMRI-GTV were: D50=50.1Gy [44.6Gy, 56.0Gy], γ=0.84 [0.53, 1.21], α/β=0.0Gy (95%CI was undefined). Conclusion: The linear-quadratic Poisson TCP model was better fit when the prostate gland was considered as responsible target than with mpMRI-GTV. This is compatible with the results of the comparison of the dose distributions among BR and BC groups and with the results achieved with the multivariate logistic model regarding gEUD 2Gy . Probably limitations of mpMRI in defining the GTV explain these results. Another explanation could be the relatively homogeneous dose prescription and the relatively low number of recurrences.

scholarly journals Near-complete regression 19 years after Gamma Knife radiosurgery of vestibular schwannoma with massive pseudoprogression: case report

2020 ◽  
pp. 1-4
Author(s):  
Lai-fung Li ◽  
Chung-ping Yu ◽  
Anderson Chun-on Tsang ◽  
Benedict Beng-teck Taw ◽  
Wai-man Lui
Keyword(s):  
Gamma Knife ◽  
Vestibular Schwannoma ◽  
Complete Resolution ◽  
Tumor Volume ◽  
Gamma Knife Radiosurgery ◽  
Mass Effect ◽  
Surgical Removal ◽  
Complete Regression ◽  
Wide Range ◽  
Over Time

Gamma Knife radiosurgery (GKRS) is a frequent treatment choice for patients with small- to moderate-sized vestibular schwannoma (VS). However, pseudoprogression after GKRS is commonly observed, with a reported incidence ranging from 7% to 77%. The wide range of the reported incidence of pseudoprogression reflects the fact that there is no consensus on how it should be diagnosed.The authors present the case of a 66-year-old woman who had a 2.5-cm right-sided VS treated with GKRS in 1997. The first posttreatment MRI obtained 5 months later showed that the tumor volume had increased to 9.7 cm3. The tumor volume increased further and reached its peak 24 months after treatment at 20.9 cm3, which was a 161% increase from pretreatment volume. Thereafter, the tumor shrank gradually and mass effect on the brainstem reduced over time. By 229 months after treatment, the tumor volume was 1.0 cm3, equaling 12.5% of pretreatment tumor volume, or 4.8% of peak tumor volume after treatment. This case demonstrates that if a patient remains asymptomatic despite a dramatic increase in tumor volume after GKRS, observation remains an option, because even a very sizable tumor can shrink with near-complete resolution. Patients undergoing GKRS for VS should be counseled regarding the possibility of pseudoprogression, and followed carefully over time while avoiding premature decisions for surgical removal after treatment.

Local tumour control and eye preservation after gamma-knife radiosurgery of choroidal melanomas

2013 ◽  
Vol 98 (2) ◽  
pp. 218-223 ◽  
Author(s):  
Werner Wackernagel ◽  
Etienne Holl ◽  
Lisa Tarmann ◽  
Christoph Mayer ◽  
Alexander Avian ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Local Tumour ◽  
Choroidal Melanomas

Long-term quality of life and tumour control following gamma knife radiosurgery for vestibular schwannoma

2013 ◽  
Vol 156 (2) ◽  
pp. 389-396 ◽  
Author(s):  
Theresa Wangerid ◽  
Jiri Bartek ◽  
Mikael Svensson ◽  
Petter Förander
Keyword(s):  
Quality Of Life ◽  
Gamma Knife ◽  
Vestibular Schwannoma ◽  
Gamma Knife Radiosurgery ◽  
Tumour Control

scholarly journals Prostate cancer tumour control probability modelling for external beam radiotherapy based on multi-parametric MRI-GTV definition

2020 ◽  
Author(s):  
Ilias Sachpazidis ◽  
Panayiotis Mavroidis ◽  
Constantinos Zamboglou ◽  
Christina Marie Klein ◽  
Anca-Ligia Grosu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Patients ◽  
Radiation Treatment ◽  
Prostate Gland ◽  
Multivariate Logistic Regression Model ◽  
Biochemical Relapse ◽  
Linear Quadratic ◽  
Tumour Control ◽  
Tumour Control Probability

Abstract Purpose: To evaluate the applicability and estimate the radiobiological parameters of linear-quadratic Poisson tumour control probability (TCP) model for primary prostate cancer patients for two relevant target structures (prostate gland and GTV). The TCP describes the dose–response of prostate after definitive radiotherapy (RT). Also, to analyse and identify possible significant correlations between clinical and treatment factors such as planned dose to prostate gland, dose to GTV, volume of prostate and mpMRI-GTV based on multivariate logistic regression model. Methods: The study included 129 intermediate and high-risk prostate cancer patients (cN0 and cM0), who were treated with image-guided intensity modulated radiotherapy (IMRT) +/- androgen deprivation therapy with a median follow-up period of 81.4 months (range: 42.0 - 149.0) months. Tumour control was defined as biochemical relapse free survival according to the Phoenix definition (BRFS). MpMRI-GTV was delineated retrospectively based on a pre-treatment multi-parametric MR imaging (mpMRI), which was co-registered to the planning CT. The clinical treatment planning procedure was based on prostate gland, delineated on CT imaging modality. Furthermore, we also fitted the clinical data to TCP model for the two considered targets for the 5-year follow-up after radiation treatment, where our cohort was composed of a total number of 108 patients, of which 19 were biochemical relapse (BR) patients.Results: For the median follow-up period of 81.4 months (range: 42.0 - 149.0) months, our results indicated an appropriate α/β=1.3 Gy for prostate gland and α/β=2.9 Gy for mpMRI-GTV. Only for prostate gland, EQD2 and gEUD2Gy were significantly lower in the biochemical relapse (BR) group compared to the biochemical control (BC) group. Fitting results to the linear-quadratic Poisson TCP model for prostate gland and α/β=1.3 Gy were D50=66.8 Gy with 95%CI [64.6 Gy, 69.0 Gy], and γ=3.8 with 95%CI [2.6, 5.2]. For mpMRI-GTV and α/β=2.9 Gy, D50 was 68.1 Gy with 95%CI [66.1 Gy, 70.0 Gy], and γ=4.5 with 95%CI [3.0, 6.1]. Finally, for the 5-year follow-up after the radiation treatment, our results for the prostate gland were: D50=64.6Gy [61.6Gy, 67.4Gy], γ=3.1 [2.0, 4.4], α/β=2.2Gy (95%CI was undefined). For the mpMRI-GTV, the optimizer was unable to deliver any reasonable results for the expected clinical D50 and α/β. The results for the mpMRI-GTV were D50=50.1Gy [44.6Gy, 56.0Gy], γ=0.8 [0.5, 1.2], α/β=0.0Gy (95%CI was undefined). For a follow-up time of 5 years and a fixed α/β=1.6Gy, the TCP fitting results for prostate gland were D50=63.9Gy [60.8Gy, 67.0Gy], γ=2.9 [1.9, 4.1], and for mpMRI-GTV D50=56.3Gy [51.6Gy, 61.1Gy], γ=1.3 [0.8, 1.9].Conclusion: The linear-quadratic Poisson TCP model was better fit when the prostate gland was considered as responsible target than with mpMRI-GTV. This is compatible with the results of the comparison of the dose distributions among BR and BC groups and with the results achieved with the multivariate logistic model regarding gEUD2Gy. Probably limitations of mpMRI in defining the GTV explain these results. Another explanation could be the relatively homogeneous dose prescription and the relatively low number of recurrences. The failure to identify any benefit for considering mpMRI-GTV as the target responsible for the clinical response is confirmed when considering a fixed α/β=1.6Gy, a fixed follow-up time for biochemical response at 5 years or Gleason score differentiation.

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