International Journal of Cancer Therapy and Oncology
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Improving the efficiency of CTDIw annual measurements with established 16 cm: 32 cm phantom ratios
Get PDFPurpose: To validate the use of the 16 cm CTDI phantom to estimate the 32 cm phantom CTDIw with tabulated data from previous years.Methods: A retrospective analysis of CTDI measurements was performed from the annual physics testing reports of four Siemens Symbia (Emotion) T6, one Siemens Symbia (Emotion) T16, one Siemens Sensation Open, one Siemens Sensation 16, one Siemens Sensation 32, two GE LightSpeed 16 and five GE VCT CT scanners. For each annual report, the ratio of the 16 cm: 32 cm CTDI phantom measurements was calculated from mAs-normalized CTDI100. The ratios from a) the acceptance test, b) one year after the acceptance test or c) an average ratio of all of the previous years (range 4-8 years), were then used to estimate 32 cm CTDI phantom measurements based on active 16 cm CTDI measurements. The average percent difference between measured and calculated CTDIw was determined per scanner for all years.Results: The most accurate results were obtained when using the average ratios of all the previous years, -2% to 3% difference across all scanner models. For the ratios of the year after the acceptance test, the difference ranged from -3% to 7%, while the data estimated from the acceptance testing results yielded the largest percent difference -4% to 8%. The 64-detector row system estimates displayed the greatest variation, followed by the 16-detector row scanners, while the 6-detector row system estimates were the most accurate.Conclusion: Compared to the Siemens and GE specified CTDI limits of ± 15-30% , the variation in the estimated 32 cm phantom CTDIw values was 2-15 times lower, dependent on the scanner model and method of estimation. The variation was considerably less (2-3%) with ratios of all the previous years, perhaps indicative of year to year variations that can result in greater error.------------------------------Cite this article as: Dodge C, Gress D. Improving the efficiency of CTDIw annual measurements with established 16 cm: 32 cm phantom ratios. Int J Cancer Ther Oncol 2014; 2(2):020220. DOI: 10.14319/ijcto.0202.2
Clinical study on the sensitivity test guided hepato-arterial/portal-vein chemotherapy in patients with unresectable hepatocellar carcinoma
Get PDFPurpose: Approximately 20 % of tumors have the opportunity to be resected in patients with hepatocellar carcinoma (HCC) and their prognoses were acceptable. For the unrespectable HCC, however, the outcomes were rather poor because the specialty of the tumor blood supply and the tumor was insensitive to the chemotherapy drug. The objective of this study was to find sensitive drugs for individual patients and determine the safety and antitumor activity of hepatic intra-arterial and portal vein infusion chemotherapy. Methods: A total of 120 patients with the mean patient age of 56 years and with unresectable HCC were randomly divided into experimental group and control group. The experiment group was infused through an intra-arterial and portal vein catheter 3 different drugs were chosen by the results of drug sensitive test, whereas the control group was treated for TACE. The changes in tumor-size and AFP, two-step operation rate, survival rate, and complications were observed in these patients. Results: The tumor size reduced in 28(47.6 %) cases, stabilized in 14(23.3 %) cases, and progressed in 18(30 %) cases in experimental group as measured by CT or MRI after six chemotherapy cycles, whereas the corresponding data was 17(28.5 %) cases, 7(11.5 %) cases and 36(60 %) cases in the control group (P < 0.05). The AFP was declined in 51 cases in experimental group and in 30 cases in control group (P < 0.05). In the experimental group, the median follow-up time was 21 months; the overall survival rates (OS) of 6 months, 12 months, and 18 months were 86 %, 72 %, and 65 %, respectively. In the control group, the median follow-up time was 16 months; the OS rates of 6 months and 12 months were 58 % and 40 %, respectively. Six patients in the experimental group and 3 patients in the control group had two-step operation. There was no severe incidence of complications in both groups. In the experimental group, 2 (3 %) patients had wound infection, 8 cases had the chemotherapy relative diarrhea, and 18 (30 %) cases had grade Ⅰ or Ⅱ bone marrow suppression. In the control group, the chemotherapy relative diarrhea were 15 (25 %) cases and grade Ⅰ or Ⅱ bone marrow suppression were 33 (55 %) cases. Conclusion: The artery and portal vein pump transfusion chemotherapy guided by drug sensitive test was efficient for HCC treatment. The patients can get longer OS and lower complication incidence.--------------------------------------------------------Cite this article as: Wu D, Wei S, Luo C, Wu X, Feng Y, Zhang F, Nie L, Xia X. Clinical study on the sensitivity test guided hepato-arterial/portal -vein chemotherapy in patients with unresectable hepatocellar carci-noma. Int J Cancer Ther Oncol 2014; 2(2):02029. DOI: 10.14319/ijcto.0202.
A case report on nasolabial cyst
Get PDFThe nasolabial cyst (NLC) is an uncommon clinical entity and is generally unilateral. It is benign in nature and is embryonic in origin and only one case with malignancy has been reported. It is located in the nasolabial folds. Most of time it is an asymptomatic deformity of face and rarely can result in nasal obstruction if it is bilateral. Its diagnosis is clinical and treatment is surgical excision. A 16 years brown female patient presented with bulging in left nasolabial region. She was treated with surgery...........................................................Cite this article as:Goyal S, Sharma J, Sharma N. A case report on nasolabial cyst. Int J Cancer Ther Oncol 2014; 2(3):020311. DOI: 10.14319/ijcto.0203.1
Deformable image and dose registration evaluation using two commercial programs
Get PDFPurpose: To evaluate the daily dose delivered to the patients using daily imaging.Methods: Thirty (n = 30) patients that were previously treated in our clinic (10 prostate, 10 SBRT lung and 10 abdomen) were used in this study. The patients’ plans were optimized and calculated using the Pinnacle treatment planning system. The daily CBCT scans were retrieved and imported into the Velocity and RayStation software along with the corresponding planning CTs, structure sets and 3D dose distributions. In addition, the critical structures were contoured on each CBCT by the prescribing physician and were included in the evaluation of the daily delivered dose. After registering each CBCT scan to the planning CT using deformable registration, the dose volume histograms (DVH) for the organs at risk (OAR) and the respective planning target volumes (PTV) were calculated in Velocity and Raystation.Results: For the prostate patients, we observed daily volume changes for the bladder, rectum and sigmoid. The DVH analysis for those patients showed variation in the sparing of the critical structures while PTV coverage showed no significant changes. Similar results were observed for patients with abdominal targets. In contrast, in SBRT lung patients, the DVH for the critical structures and the PTV were comparable to those from the initial treatment plan. By using daily CBCT dose reconstruction, we proved PTV coverage for prostate and abdominal targets is adequate. However, there is significant dosimetric change for the OAR. These changes were random with no apparent trending. For lung SBRT patients, the delivered daily dose for both PTV and OAR is comparable to the planned dose with no significant differences.Conclusion: Daily tracking of the delivered dose is feasible. The doses can be evaluated only if the OARs have been segmented taken into account any daily anatomical changes and not by deformation of the structures along.-------------------Cite this article as: Tuohy R, Bosse C, Mavroidis P, Shi Z, Crownover R, Papanikolaou N, Stathakis S. Deformable image and dose registration evaluation using two commercial programs. Int J Cancer Ther Oncol 2014; 2(2):020242. DOI: 10.14319/ijcto.0202.4
A plan quality classifier derived with overlap-wall-histogram of hollow organs for automatic IMRT plan quality control of prostate cancer cases
Get PDFPurpose: We developed a plan quality classification model to assess IMRT plan quality of prostate cancer patients for automatic plan quality control. Methods: For hollow organs such as rectum and bladder, dose-wall-histogram (DWH) was used to evaluate OAR dose sparing in our institution. Correspondingly, we proposed a new descriptor called overlap-wall-histogram (OWH) to describe the complex spatial relationship between PTV and a hollow organ. Two metrics calculated from the OWH and DWH are introduced to quantitatively evaluate the difficulty of patient geometry for planning and plan quality in terms of OAR sparing, respectively. A linear correlation between these two metrics was observed after plotting plan quality metric as a function of geometry difficulty metric studied from a database of prostate cases treated in our institution with acceptable plan quality. Thus, a fitting line was built acting as the boundary of high quality and poor quality plans. A query plan falling above the boundary is assessed as high quality, vice versa poor quality. Results: 15 prostate IMRT plans were used to test our model. One was identified as poor quality and the others were common-level. After re-planning all plans, the dose constraints for bladder wall W75 (percentage of wall receiving more than 75Gy), W70, W65 and W60 can be reduced by 3.34%, 3%, 6.99%, 6.54% for that poor quality plan and 1.11%, 0.95%, 1.45% and 1.81% averagely for the common-level quality group, without sacrificing PTV coverage and rectum dose sparing. Conclusion: An effective model was built to provide automatic IMRT plan quality control by evaluating hollow OAR dose sparing for prostate cancer patients. Furthermore, for the query plan with poor quality, potential improvement of plan quality can be estimated and a good reference plan with similar or harder geometry can be automatically chosen from our database to help guide the re-planning if necessary.---------------------------Cite this article as: Song T, Tian Z, Jia X, Zhou L, Jiang SB, Gu X. A plan quality classifier derived with overlap-wall-histogram of hollow organs for automatic IMRT plan quality control of prostate cancer cases. Int J Cancer Ther Oncol 2014; 2(2):020241. DOI: 10.14319/ijcto.0202.4
Monitoring methods for skin dose in interventional radiology
Get PDFInterventional radiology makes an increasing use of X-ray for diagnostic and therapeutic procedures. The dose received by the patient sometime exceeds the threshold value of deterministic effects, and this requires monitoring of the dose delivered to the patients. Delivered dose could be assessed through either direct or indirect methods. The direct methods use dosimeters that are placed on the skin during the procedure, whereas, the indirect methods are based on measured quantities derived from the equipment itself. Each method has its own limitations; however, the main concern is the ability to measure the dose more accurately due to complexity of the anatomical structures of the patient and the variable course of each procedure. This review article summarizes the principle and main advantages and disadvantages of each method. A comparison of the performances of each method for interventional fluoroscopy and radiography in its ability to monitor the patient’s skin dose is provided.
Comparative dosimetric analysis of IMRT and VMAT (RapidArc) in brain, head and neck, breast and prostate malignancies
Get PDFPurpose: Intensity modulated radiotherapy (IMRT) in the recent past has established itself as a gold standard for organs at risk (OAR) sparing, target coverage and dose conformity. With the advent of a rotational treatment technology such as volumetric modulated arc therapy (VMAT), an inter-comparison is warranted to address the advantages and disadvantages of each technique. Methods: Twenty patients were selected retrospectively from our patient database. Sites included were brain, head and neck, chest wall, and prostate, with five patients for each site. For all the selected patients, both the IMRT and VMAT treatment plans were generated. Plan comparison was done in terms of OAR dose, dose homogeneity index (HI), dose conformity index (CI), target coverage, low isodose volumes, monitor units (MUs), and treatment time.Results: The VMAT showed better sparing of “parotids minus planning target volume (PTV)”, spinal cord and head of femur as compared to the IMRT. The lung V40 for VMAT was lower, whereas the lung V10, contralateral lung mean dose, contralateral breast mean dose and mean body dose were lower with IMRT for chest wall cases. Both the VMAT and IMRT achieved comparable HI except for the brain site, where IMRT scored over VMAT. The CI achieved by the IMRT and VMAT were similar except for chest wall cases, whereas the VMAT achieved better dose conformity. The target coverage was comparable with both the plans. The VMAT clearly scored over IMRT in terms of average MUs (486 versus 812 respectively) and average treatment time (2.54 minutes versus 5.54 minutes) per treatment session. Conclusion: The VMAT (RapidArc) has a potential to generate treatment plans for various anatomical sites which are comparable with the corresponding IMRT plans in terms of OAR sparing and plan quality parameters. The VMAT significantly reduces treatment time as compared to the IMRT, thus VMAT can increase the throughput of a busy radiotherapy department
GPU-Monte Carlo based fast IMRT plan optimization
Get PDFPurpose: Intensity-modulated radiation treatment (IMRT) plan optimization needs pre-calculated beamlet dose distribution. Pencil-beam or superposition/convolution type algorithms are typically used because of high computation speed. However, inaccurate beamlet dose distributions, particularly in cases with high levels of inhomogeneity, may mislead optimization, hindering the resulting plan quality. It is desire to use Monte Carlo (MC) methods for beamlet dose calculations. Yet, the long computational time from repeated dose calculations for a number of beamlets prevents this application. It is our objective to integrate a GPU-based MC dose engine in lung IMRT optimization using a novel two-steps workflow.Methods: A GPU-based MC code gDPM is used. Each particle is tagged with an index of a beamlet where the source particle is from. Deposit dose are stored separately for beamlets based on the index. Due to limited GPU memory size, a pyramid space is allocated for each beamlet, and dose outside the space is neglected. A two-steps optimization workflow is proposed for fast MC-based optimization. At first step, a rough dose calculation is conducted with only a few number of particle per beamlet. Plan optimization is followed to get an approximated fluence map. In the second step, more accurate beamlet doses are calculated, where sampled number of particles for a beamlet is proportional to the intensity determined previously. A second-round optimization is conducted, yielding the final result.Results: For a lung case with 5317 beamlets, 105 particles per beamlet in the first round, and 108 particles per beam in the second round are enough to get a good plan quality. The total simulation time is 96.4 sec.Conclusion: A fast GPU-based MC dose calculation method along with a novel two-step optimization workflow are developed. The high efficiency allows the use of MC for IMRT optimizations.--------------------------------Cite this article as: Li Y, Tian Z, Shi F, Jiang S, Jia X. GPU-Monte Carlo based fast IMRT plan optimization. Int J Cancer Ther Oncol 2014; 2(2):020244. DOI: 10.14319/ijcto.0202.4
Radiation dose reduction without degrading image quality during computed tomography examinations: Dosimetry and quality control study
Get PDFPurpose: Computed tomography (CT), is an X-ray procedure that generates high quality cross-sectional images of the body, and by comparison to other radiological diagnosis, is responsible for higher doses to patients. This work studies the doses and image qualities produced from the default primary scanning factors of a Siemens CT machine and afterwards came up with scanning protocols that allow radiologists to obtain the necessary diagnostic information while reducing radiation doses to as low as reasonably achievable. Methods: Approximately 1000 CT scans from mostly common examinations; head, thorax, abdomen and pelvis routines were selected and analyzed for their image quality and radiation doses over a two year interval. Dose measurements were performed for the same routines using Computed Tomography Dose Index (CTDI) phantoms, RTI barracuda system with electrometer, and CT dose Profiler detector to evaluate the doses delivered during these CT procedures. Subsequently, image quality checks were performed using the CT Catphan 600 and anthropomorphic phantoms. CTDI and Dose Length Product (DLP) values were calculated for each scan. From analyzing these measurements, the appropriate machine scanning parameters were adjusted to reduce radiation does while at the same time providing good image quality.Results: Doses to patients using the default head sequence protocol had an average CTDIvol value of 65.45 mGy and a range of 7.10-16.80 mGy for thorax, abdomen and pelvis examinations whiles the new protocol had an average CTDIvol of 58.32 mGy for the head and a range of 3.83-15.24 mGy for the truck region. The DLP value for default head scans decreased from an average of 2279.85 mGy.cm to 874.53 mGy.cm with the new protocol. Tube potentials (KV) and tube current-time (mAs) had an effect on spatial resolution and low contrast detectability as well as doses. Conclusion: From the new protocols, lower values of KV and mAs together with other factors were enough to produce acceptable level of image quality which leads to adequate diagnosis without unnecessary doses to patients.......................................................Cite this article as:Acquah GF, Schiestl B,Cofie AY, Nkansah JO. Radiation dose reduction without degrading image quality during computed tomography examinations: Dosimetry and quality control study. Int J Cancer Ther Oncol 2014; 2(3):02039. DOI: 10.14319/ijcto.0203.
Dosimetric study of RapidArc plans with flattened beam (FB) and flattening filter-free (FFF) beam for localized prostate cancer based on physical indices
Get PDFPurpose: To identify the continual diversity between flattening photon beam (FB) and Flattening Filter Free (FFF) photon beams for localized prostate cancer; and to determine potential benefits and drawbacks of using unflattened beam for this type of treatment.Methods: Eight prostate cases including seminal vesicles selected for this study. The primary planning target volume (PTVP) and boost planning target volume (PTVB) were contoured. The total prescription dose was 78 Gy (56 Gy to PTVP and an additional 22 Gy to PTVB). For all cases, treatment plans using 6MV with FB and FFF beams with identical dose-volume constraints, arc angles and number of arcs were developed. The dose volume histograms for both techniques were compared for primary target volume and critical structures.Results: A low Sigma index (FFF: 1.65 + 0.361; FB: 1.725 + 0.39) indicating improved dose homogeneity in FFF beam. Conformity index (FFF: 0.994 + 0.01; FB: 0.993 + 0.01) is comparable for both techniques. Minimal difference of Organ at risk mean dose was observed. Normal tissue integral dose in FB plan resulted 1.5% lower than FFF plan. All the plans displayed significant increase (1.18 times for PTVP and 1.11 for PTBB) in the average number of necessary MU with FFF beam.Conclusion: Diversity between FB and FFF beam plans were found. FFF beam accelerator has been utilized to develop clinically acceptable Rapid Arc treatment plans for prostate cancer with 6 MV.---------------------------------Cite this article as: Rout BK, Muralidhar KR, Ali M, Shekar MC, Kumar A. Dosimetric study of RapidArc plans with flattened beam (FB) and flattening filter-free (FFF) beam for localized prostate cancer based on physical indices. Int J Cancer Ther Oncol 2014; 2(4):02046. DOI: 10.14319/ijcto.0204.