International Journal of Cancer Therapy and Oncology
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Treatment planning study comparing proton therapy, RapidArc and intensity modulated radiation therapy for a synchronous bilateral lung cancer case
No full textPurpose: The main purpose of this study is to perform a treatment planning study on a synchronous bilateral non-small cell lung cancer case using three treatment modalities: uniform scanning proton therapy, RapidArc, and intensity modulated radiation therapy (IMRT). Methods: The maximum intensity projection (MIP) images obtained from the 4 dimensional-computed tomography (4DCT) scans were used for delineation of tumor volumes in the left and right lungs. The average 4D-CT was used for the treatment planning among all three modalities with identical patient contouring and treatment planning goal. A proton therapy plan was generated in XiO treatment planning system (TPS) using 2 fields for each target. For a comparative purpose, IMRT and RapidArc plans were generated in Eclipse TPS. Treatment plans were generated for a total dose of 74 CGE or Gy prescribed to each planning target volume (PTV) (left and right) with 2 CGE or Gy per fraction. In IMRT and RapidArc plans, normalization was done based on PTV coverage values in proton plans. Results: The mean PTV dose deviation from the prescription dose was lower in proton plan (within 3.4%), but higher in IMRT (6.5% to 11.3%) and RapidArc (3.8% to 11.5%) plans. Proton therapy produced lower mean dose to the total lung, heart, and esophagus when compared to IMRT and RapidArc. The relative volume of the total lung receiving 20, 10, and 5 CGE or Gy (V20, V10, and V5, respectively) were lower using proton therapy than using IMRT, with absolute differences of 9.71%, 22.88%, and 39.04%, respectively. The absolute differences in the V20, V10, and V5 between proton and RapidArc plans were 4.84%, 19.16%, and 36.8%, respectively, with proton therapy producing lower dosimetric values. Conclusion: Based on the results presented in this case study, uniform scanning proton therapy has a dosimetric advantage over both IMRT and RapidArc for a synchronous bi-lateral NSCLC, especially for the normal lung tissue, heart, and esophagus sparing. Further studies on a large group of patients with bi-lateral lung cancer are required to validate the dosimetric superiority of proton therapy over the IMRT and RapidArc.-------------------------------Cite this article as: Rana S, Pokharel S, Zheng Y, Zhao L, Risalvato D, Vargas C, Cersonsky N. Treatment planning study comparing proton therapy, RapidArc and intensity modulated radiation therapy for a synchronous bilateral lung cancer case. Int J Cancer Ther Oncol 2014; 2(2):020216. DOI:10.14319/ijcto.0202.1
Scintillating fiber based in-vivo dose monitoring system to the rectum in proton therapy of prostate cancer: A Geant4 Monte Carlo simulation
Get PDFPurpose: To construct a dose monitoring system based on an endorectal balloon coupled to thin scintillating fibers to study the dose to the rectum in proton therapy of prostate cancer.Method: A Geant4 Monte Carlo toolkit was used to simulate the proton therapy of prostate cancer, with an endorectal balloon and a set of scintillating fibers for immobilization and dosimetry measurements, respectively.Results: A linear response of the fibers to the dose delivered was observed to within less than 2%. Results obtained show that fibers close to the prostate recorded higher dose, with the closest fiber recording about one-third of the dose to the target. A 1/r2 (r is defined as center-to-center distance between the prostate and the fibers) decrease was observed as one goes toward the frontal and distal regions. A very low dose was recorded by the fibers beneath the balloon which is a clear indication that the overall volume of the rectal wall that is exposed to a higher dose is relatively minimized. Further analysis showed a relatively linear relationship between the dose to the target and the dose to the top fibers (total 17), with a slope of (-0.07 ± 0.07) at large number of events per degree of rotation of the modulator wheel (i.e., dose).Conclusion: Thin (1 mm × 1 mm), long (1 m) scintillating fibers were found to be ideal for real time in-vivo dose measurement to the rectum during proton therapy of prostate cancer. The linear response of the fibers to the dose delivered makes them good candidates as dosimeters. With thorough calibration and the ability to define a good correlation between the dose to the target and the dose to the fibers, such dosimeters can be used for real time dose verification to the target.-----------------------------------Cite this article as: Tesfamicael BY, Avery S, Gueye P, Lyons D, Mahesh M. Scintillating fiber based in-vivo dose monitoring system to the rectum in proton therapy of prostate cancer: A Geant4 Monte Carlo simulation. Int J Cancer Ther Oncol 2014; 2(2):02024.DOI: http://dx.doi.org/10.14319/ijcto.0202.
Dosimetric comparison of 3DCRT versus IMRT in whole breast irradiation of early stage breast cancer
Get PDFPurpose: The counseling regarding the treatment option is an important objective in the management of early stages breast cancer. In this study, we attempt to compare and analyze the dosimetric aspects of 3DRT over IMRT in the whole breast radiotherapy.Methods and Materials: Both right and left sided computed tomography simulations of 14 women with early stage breast cancer were used for our retrospective study to compare the 3DCRT and IMRT. The dose prescribed was 50 Gy in 25 fractions to the whole breast PTV. The PTV was defined by adding unequal margins to the directional safety margin status of each lumpectomy cavity (i.e., medial, lateral, superior, inferior and deep margins measured from the tumor front after the examination of the surgical specimen: 2, 1.5, and 1 cm for resection margins < 1 cm, 1-2 cm, and > 2cm, respectively). And than modified so that it was no longer closer than 3mm to the skin surface and was no deep than the lung –chest interface. The prescribed dose delivered in 5 fractions per week schedule. Treatment plans were compared for target minimum dose, maximum dose, mean dose, conformity index, heterogeneity index and doses to organs at risk were compared and analysed.Results: The target coverage was achieved with 90% prescription to the 95% of the PTV. Conformity to the PTV was significantly higher with 3DCRT technique than IMRT. 3DCRT technique seems better in sparing critical organs parameters like lung V20 and Mean, heart, V25, Maximum, both lungs V20, Mean and Dose to the Normal Healthy tissue.Conclusion: We conclude from our study that treatment technique selection for whole Breast irradiation is an important factor in sparing the adjacent normal structures and in determining the associated risk. 3DCRT produces better conformity and heterogeneity indices of the target volume, also reduces dose to OARs the 3DCRT reduces the risk of radiation induced heart diseases.......................................................Cite this article as:Ashraf M, Janardhan N, Bhavani P, Shivakumar R, Ibrahim S, Reddy PY, Surrendharen J, Sarangnathan B, Johnson B, Madhuri B, Dar RA. Dosimetric comparison of 3DCRT versus IMRT in whole breast irradiation of early stage breast cancer. Int J Cancer Ther Oncol 2014; 2(3):020318. DOI: 10.14319/ijcto.0203.1
Commissioning and quality assurances of the Intrabeam Intra-Operative radiotherapy unit
Get PDFPurpose: The authors report comprehensive commissioning and quality assurance (QA) procedures for Intrabeam, Intra-Operative radiotherapy (IORT) unit. The Intrabeam system miniature X-ray source is a 50 kV and 40 µA unit. Methods: The authors’ tests include measurements of output, beam deflection, isotropy, kVp and mAs measurements, quality index, isodose, reproducibility, linearity, depth dose verification, and 3D dose distribution. IC ionization chamber and the UNIDOSE dosimeter were used for the output commissioning. Probe adjuster/ionization chamber holder (PAICH) was used to check the mechanical straightness of the probe. For radiation tests, NACP parallel plate chamber, Standard Imaging electrometer, 30 × 30 × 30 cm3 IAEA water phantom, solid water slabs, EDR-2 Films with RIT software, and ionization based survey meters were used. Unfors Xi platinum edition kVp meter was used to measure the kVp and mAs. Results: In mechanical QA test, X-Beam position (-0.09 mm), Y-Beam position (0.01 mm), and radial position (0.11 mm) errors were within the tolerance level. Isotropy test with PDA, survey meter, ion chamber, and film measurements also produced results within the specifications. Output measurements with PAICH and external chamber measurements were matched. Beam quality, linearity, and reproducibility values were ascertained at 50KV and 40 µA and found to be within limits. Isodose, 3D dose distribution, transverse, and horizontal profiles showed the good isotropy of the source. Conclusion: The authors’ methodology provides comprehensive commissioning and calibration procedures for the Intrabeam system
3D dictionary learning based iterative cone beam CT reconstruction
Get PDFPurpose: This work is to develop a 3D dictionary learning based cone beam CT (CBCT) reconstruction algorithm on graphic processing units (GPU) to improve the quality of sparse-view CBCT reconstruction with high efficiency. Methods: A 3D dictionary containing 256 small volumes (atoms) of 3 × 3 × 3 was trained from a large number of blocks extracted from a high quality volume image. On the basis, we utilized cholesky decomposition based orthogonal matching pursuit algorithm to find the sparse representation of each block. To accelerate the time-consuming sparse coding in the 3D case, we implemented the sparse coding in a parallel fashion by taking advantage of the tremendous computational power of GPU. Conjugate gradient least square algorithm was adopted to minimize the data fidelity term. Evaluations are performed based on a head-neck patient case. FDK reconstruction with full dataset of 364 projections is used as the reference. We compared the proposed 3D dictionary learning based method with tight frame (TF) by performing reconstructions on a subset data of 121 projections. Results: Compared to TF based CBCT reconstruction that shows good overall performance, our experiments indicated that 3D dictionary learning based CBCT reconstruction is able to recover finer structures, remove more streaking artifacts and also induce less blocky artifacts. Conclusion: 3D dictionary learning based CBCT reconstruction algorithm is able to sense the structural information while suppress the noise, and hence to achieve high quality reconstruction under the case of sparse view. The GPU realization of the whole algorithm offers a significant efficiency enhancement, making this algorithm more feasible for potential clinical application.-------------------------------Cite this article as: Bai T, Yan H, Shi F, Jia X, Lou Y, Xu Q, Jiang S, Mou X. 3D dictionary learning based iterative cone beam CT reconstruction. Int J Cancer Ther Oncol 2014; 2(2):020240. DOI: 10.14319/ijcto.0202.4
The openness of pluripotent epigenome - Defining the genomic integrity of stemness for regenerative medicine
Get PDFThis article is an editorial, and it doesn't include an abstract. Full text of this article is available in HTML and PDF.Cite this article as: Parsons XH. The openness of pluripotent epigenome - Defining the genomic Integrity of stemness for regenerative medicine. Int J Cancer Ther Oncol 2014; 2(1):020114.DOI: http://dx.doi.org/10.14319/ijcto.0201.1
Delivering a radiation protection dividend: systemic capacity-building for the radiation safety profession in Africa
Get PDFMany African countries planning to enter the nuclear energy “family” have little or no experience of meeting associated radiation safety demands, whether operational or regulatory. Uses of radiation in medicine in the continent, whether for diagnostic or clinical purposes, are rapidly growing while the costs of equipment, and hence of access to services, are falling fast. In consequence, many patients and healthcare workers are facing a wide array of unfamiliar challenges, both operational and ethical, without any formal regulatory or professional framework for managing them safely. This, combined with heighted awareness of safety issues post Fukushima, means the already intense pressure on radiation safety professionals in such domains as NORM industries and security threatens to reach breaking point. A systematic competency-based capacity-building programme for RP professionals in Africa is required (Resolution of the Third AFRIRPA13 Regional Conference, Nairobi, September 2010). The goal is to meet recruitment and HR needs in the rapidly emerging radiation safety sector, while also addressing stakeholder concerns in respect of promoting and meeting professional and ethical standards. The desired outcome is an RP “dividend” to society as a whole. A curriculum model is presented, aligned to safety procedures and best practices such as Safety Integrity Level and Layer of Protection analysis; it emphasizes proactive risk communication both with direct and indirect stakeholders; and it outlines disciplinary options and procedures for managers and responsible persons for dealing with unsafe or dangerous behavior at work. This paper reports on progress to date. It presents a five-tier development pathway starting from a generic foundation course, suitable for all RP professionals, accompanied by specialist courses by domain, activity or industry. Delivery options are discussed. Part of the content has already been developed and delivered as MiLoRAD, based on extensive experience training radiation safety personnel in the United States
Dose-to-medium vs. dose-to-water: Dosimetric evaluation of dose reporting modes in Acuros XB for prostate, lung and breast cancer
Get PDFPurpose: Acuros XB (AXB) dose calculation algorithm is available for external beam photon dose calculations in Eclipse treatment planning system (TPS). The AXB can report the absorbed dose in two modes: dose-to-water (Dw) and dose-to-medium (Dm). The main purpose of this study was to compare the dosimetric results of the AXB_Dm with that of AXB_Dw on real patient treatment plans. Methods: Four groups of patients (prostate cancer, stereotactic body radiation therapy (SBRT) lung cancer, left breast cancer, and right breast cancer) were selected for this study, and each group consisted of 5 cases. The treatment plans of all cases were generated in the Eclipse TPS. For each case, treatment plans were computed using AXB_Dw and AXB_Dm for identical beam arrangements. Dosimetric evaluation was done by comparing various dosimetric parameters in the AXB_Dw plans with that of AXB_Dm plans for the corresponding patient case. Results: For the prostate cancer, the mean planning target volume (PTV) dose in the AXB_Dw plans was higher by up to 1.0%, but the mean PTV dose was within ±0.3% for the SBRT lung cancer. The analysis of organs at risk (OAR) results in the prostate cancer showed that AXB_Dw plans consistently produced higher values for the bladder and femoral heads but not for the rectum. In the case of SBRT lung cancer, a clear trend was seen for the heart mean dose and spinal cord maximum dose, with AXB_Dw plans producing higher values than the AXB_Dm plans. However, the difference in the lung doses between the AXB_Dm and AXB_Dw plans did not always produce a clear trend, with difference ranged from -1.4% to 2.9%. For both the left and right breast cancer, the AXB_Dm plans produced higher maximum dose to the PTV for all cases. The evaluation of the maximum dose to the skin showed higher values in the AXB_Dm plans for all 5 left breast cancer cases, whereas only 2 cases had higher maximum dose to the skin in the AXB_Dm plans for the right breast cancer. Conclusion: The preliminary dosimetric results from our clinical study showed that the selection of either Dm or Dw in AXB is less likely to produce significant dosimetric differences in the clinical environment. However, the difference between the AXB_Dm and AXB_Dw calculations depends on the disease site, and even for the same type of disease (e.g., lung cancer), the results are patient specific
Public exposure from I-131 hospitalized isolated patients in NIMRA Jamshoro Pakistan
Get PDFPurpose/ Background: To treat the cancerous tissues the unsealed radioisotopes are being in clinical practice since 7 decades. From these unsealed sources, I-131 is the choice of treatment for the treating thyroid cancers. Orally administered I-131 patients are to be kept isolated in hospital for some period until captured activity in the body reaches to national and international limits for the avoidance of unacceptably high radiation exposures to patients' family members and the general public to keep ALARA (as low as reasonably achievable) principal in mind. The main rationale of this study was to calculate the exposure/dose of the general public. Material and Methods: This work presents the exposure rate and dose to the general public in the corridor and the non-radioactive patients admitted in adjacent room from I-131 administered isolated patients treated at NIMRA (Nuclear Institute of Medicine and Radiotherapy) Jamshoro Pakistan. In this study exposure from 23 thyroid cancer patients treated with different activities of I-131 (50 to 200 mCi) from January 2011 to December 2012 were included. Results: The average exposure rate in the corridor was about 5.17 µSv/hr (2.14 µSv/hr to 8.15 µSv/hr) and the cumulative dose to nonradioactive patients residing in an adjacent room was 0.647 mSv (0.192 mSv to 1.664 mSv). Conclusion: This study concludes that the exposure rate to the general public especially the admitted non-radioactive patient in the adjacent room is almost within the limits of 1 mSv as specified in national and international standards.-----------------------------------------Cite this article as: Memon SA, Laghari NA, Qureshi ST, Ahmad A, Khan AA, Hussain MM. Public exposure from I-131 hospitalized isolated patients in NIMRA Jamshoro Pakistan. Int J Cancer Ther Oncol 2014; 2(2):020214. DOI: 10.14319/ijcto.0202.1
Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation
Get PDFPurpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT). We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC) simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstruction within 30 seconds.Methods: The method consists of six steps: 1) FDK reconstruction using raw projection data; 2) Rigid Registration of planning CT to the FDK results; 3) MC scatter calculation at sparse view angles using the planning CT; 4) Interpolation of the calculated scatter signals to other angles; 5) Removal of scatter from the raw projections; 6) FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC noise from the simulated scatter images caused by low photon numbers. The method is validated on one simulated head-and-neck case with 364 projection angles.Results: We have examined variation of the scatter signal among projection angles using Fourier analysis. It is found that scatter images at 31 angles are sufficient to restore those at all angles with < 0.1% error. For the simulated patient case with a resolution of 512 × 512 × 100, we simulated 5 × 106 photons per angle. The total computation time is 20.52 seconds on a Nvidia GTX Titan GPU, and the time at each step is 2.53, 0.64, 14.78, 0.13, 0.19, and 2.25 seconds, respectively. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU.Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. It accomplished the whole procedure of scatter correction and reconstruction within 30 seconds.----------------------------Cite this article as: Xu Y, Bai T, Yan H, Ouyang L, Wang J, Pompos A, Zhou L, Jiang SB, Jia X. Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation. Int J Cancer Ther Oncol 2014; 2(2):020245. DOI: 10.14319/ijcto.0202.4