International Journal of Cancer Therapy and Oncology
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The value of Gleason score and prostate-specific antigen level in predicting the need for a baseline nuclear bone scan in patients with newly diagnosed 84 prostate cancer cases
Get PDFPurpose: The objective of the present study was to correlate the prostate-specific antigen (PSA) level and Gleason score with the baseline bone scan results in patients with newly diagnosed prostate cancer and try to determine a group of patients whose risk of bone metastases is low enough to omit safely this staging modality.Methods: This retrospective study included 84 consecutive patients with newly diagnosed prostate cancer (Pca) who underwent a staging bone scan in Nuclear Medicine department between August 2013 and August 2014. Data were collected on age, bony pain, prostate-specific antigen (PSA) level and Gleason score, then, bone scan results were analyzed with respect to these parameters. Bone scan was recorded as positive, negative or equivocal. In case of equivocal lesions, a single-photon emission computed tomography combined with computed tomography (SPECT-CT) was performed allowing a better morphological precision. Results: The median age of the patients was 71, 38 years. Bone metastases were detected in 41 patients (49% of cases), bony pain was a reliable presenting sign of skeletal involvement. Both prostate-specific antigen (PSA) level and Gleason score were independent predictors of positive bone scan. However, the combination of these two parameters enhanced predictability of bone scan results. According to this study, the risk to develop a bone metastasis was very low in asymptomatic patients with PSA level < 20 ng/ml irrespective of the Gleason score or with PSA level < 30 ng/ml associated to a Gleason score < 7. Conclusion: The present study discourages the routine use of bone scan as a pre-treatment staging modality in asymptomatic patients with PSA level < 20 ng/ml irrespective of the Gleason score or with PSA level < 30 ng/ml associated to a Gleason score < 7, allowing considerable cost savings and decreasing time from diagnosis to treatment
Pediatric mature B-cell non Hodgkin lymphoma treatment with LMB-96 protocol. The Children Cancer Hospital Egypt experience
Get PDFPurpose: Burkitt lymphoma (BL) is a highly aggressive mature B-cell non-Hodgkin lymphoma (NHL) and is the fastest growing human tumor. The outcome of childhood NHL has improved steadily over the past decades through the use of intensive sequential multi-agent chemotherapy regimens.Methods: A retrospective study having all patients 18 years old or younger diagnosed with mature B cell NHL and treated at Children Cancer Hospital Egypt (CCHE). All children were treated according to the modified (LMB 96) protocol during the period between July 2007 and December 2012. Patients were followed up till June 2013.Results: Three hundred and seventy-seven patients were diagnosed with mature B cell NHL and received the LMB96 treatment protocol. The majorities were males (76.4%) with a median age of 5.3 years, and ranged from 0.1-18.0 years. The median follow-up period was 28.2 months (range 0.9-72 months). Burkitt lymphoma was the most predominant pathologic subtype (79.6%, n = 300), and abdominal mass as a primary site was the most common presentation (71.3%). Twenty seven patients (7.2%) were treated as group A, 268 (71.0%) as group B, and 82 (21.8%) patients as high risk group C. Seventy-one (18.8%) patients suffered adverse events. Major adverse events were early deaths in 17 patients (4.5%), death during induction chemotherapy seen in 18 patients (4.7%), and during maintenance therapy in 7 patients (1.8%), tumor progression in 19 patients (5.0%), and relapse in 10 patients (3.7%). Sixty-three patients (16.7%) died during the study period. The main causes of death were tumor lysis syndrome (TLS) in 25.3%, and severe sepsis during chemotherapy in 41.3% of the patients. The 3 years OS and EFS were 83.3% and 80.4% respectively for the whole groups of patients. OS and EFS were 100% for group A, and 87.5%±3.9% and 85.9±4.3% for group B. For group C BM+/CNS- patients, OS was 55.62%±15.8%, and EFS of 53.8%±15.6%. For BM+/CNS+ patients, OS and EFS were 63.2%±21.76% and 57.9%±22.1% respectively. BM-/CNS+ patients had OS 72.4%±18.8% and EFS 67.6%±19.7% at 36 months. Conclusion: TLS and chemotherapy related toxicity remains a major challenge affecting the outcome of pediatric mature B cell NHL. We identified bone marrow involvement as a risk factor affecting treatment outcome. Aggressive supportive care measures are mandatory to avoid unacceptable high toxicity related mortality
A prospective study of OAR volume variations between two different treatment planning systems in radiotherapy
Get PDFPurpose: It has been seen that there is a clinically significant variation in the volume calculated across different planning systems for the same digital imaging and communication (DICOM) contours.The purpose of this study is to investigate the difference in volumes of organs at risk when the structure sets were exported from the Eclipse ((Palo Alto, USA Version 10.0) to XIO CMS (Electa, Crawley, UK Version 4.40.00) treatment planning system (TPS) and identify how the differences occur. Methods: We prospectively analyzed the volumes of organs at risk from computerized tomography (CT) data of 54 patients. Head and neck and brain tumors were taken for this study and contoured on Eclipse treatment planning system (TPS) after importing images from CT. These contoured images were then exported using radiotherapy DICOM transfer facility to XIO CMS planning system and compared the contoured volumes with Eclipse TPS structured volumes. Results: Our analysis showed that the differences in calculated volumes of the contours for the patients between the two planning systems can be large. Mixed results are shown for different organs with the absolute volume difference ranging from -0.25 cc to 319.73 cc. These results clearly shown that the two TPS interprets the contours differently when calculating the volume, and there is a closer match with the theoretical calculated volumes with XIO CMS calculated volumes. Conclusion: Observed discrepancies were consistent between the two planning systems. This impact of contouring variability could play a role on plan quality metrics which is used as criteria for clinical trial protocol compliance
Treatment planning validation for symmetric and asymmetric motorized wedged fields
Get PDFPurpose: Wedged beam are often used in clinical radiotherapy to compensate missing tissues and dose gradients. The Elekta Precise linear accelerator supports an internal motorized wedge, which is a single large, physical wedge on a motorized carriage. In this study, the dosimetric performance of Elekta precise three dimensional treatment planning system (3DTPS) is evaluated by comparing the calculated and measured doses.Methods: The calculations were performed by the 3DTPS for symmetric as well as asymmetric fields in a source to skin distance (SSD) setup at the depth of maximum dose (dmax) as well as at 5, 10, and 20 cm depths in water phantom using 60° motorized wedges for field sizes of 4 × 4, 10 × 10, and 20 × 20 cm2 for 6 and 15 MV photon beams. Measurements were produced by Elekta Precise linear accelerator using 0.125 cc volume ionization chamber. Results: Good agreement between the measured and calculated isodose lines were found, with the maximum difference not exceed 5%. The difference between the calculated and measured data increases as the field size decreases, and the deviation in symmetric setting was less than that of asymmetric setting. The increase in wedge angle led to increase in the difference between calculated and measured data. Conclusion: The results from this study showed that the accuracy of Elekta Precise 3DTPS used with the motorized wedges for symmetric and asymmetric fields is adequate for the clinical applications under the studied experimental conditions.
Commissioning and cross-comparison of four scanning water tanks
Get PDFPurpose: Water scanning systems are commonly used for data collection to characterize dosimetric properties of photon and electron beams, and the commissioning of such systems has been previously described. The aim in this study, however, was to investigate tank-specific dependencies as well as conduct a dosimetric comparison between four distinct water scanning systems.Methods: Four water scanning systems were studied including the PTW MP3-M Phantom Tank, the Standard Imaging DoseView 3D, the IBA Blue Phantom, and the Sun Nuclear 3D Scanner. Mechanical accuracy and reproducibility was investigated by driving the chamber holder to nominal positions relative to a zero point and using a leveled caliper with 30 cm range to measure the actual position. Dosimetric measurements were also performed not only to compare percent-depth-dose (PDD) curves and profiles between tanks but also to assess dependencies such as directionality, scanning speed, and reproducibility for each tank individually. A PTW Semiflex 31010 ionization chamber with a sensitive volume of 0.125 cc was used at a Varian Clinac 2300 linear accelerator.Results: Mechanical precision was ensured to within 0.1 mm with the standard deviation (SD) of reproducibility <0.1 mm for measurements made with calipers. Dependencies on scanning direction and speed are presented. 6 MV PDDs between tanks agreed to within 0.6% relative to an averaged PDD beyond dmax and within 2.5% in the build-up region. Specifically, the maximum difference was 1.0% between MP3-M and Blue Phantom at 6.1 cm depth. Lateral profiles agreed between tanks within 0.5% in the central 80% of the field. 6 MeV PDD maximum difference was 1.3% occurring at the steepest portion, where the R50 was nevertheless within 0.6 mm across tanks. Setup uncertainties estimated at ≤1 mm are presumed to have contributed some of the difference between water tank data.Conclusion: Modern water scanning systems have achieved high accuracy across vendors, but commissioning tests nevertheless reveal tank-specific dependencies. This study not only ensures confidence in the individual systems but also provides the medical physicist with an understanding of variation in water tank properties between vendors
Dosimetry estimation of SPECT/CT for iodine 123-labeled metaiodobenzylguanidine in children
Get PDFPurpose: To evaluate the additional radiation exposure in terms of effective dose incurred by patients in the CT (computed tomography) portion of 123I-MIBG (123II-metaiodobenzylguanidine) study with SPECT/CT (Single photon emission computed tomography associated to computed tomography) in some pediatric patients of our department. Methods: Data from 123II-MIBG scans comprising 50 children were presented in this study. The contribution of total effective dose imparted by the nuclear tracer and patient's age was calculated. Effective dose from the CT portion of the examination is also estimated.SPECT acquisitions were performed with a dual-headed SPECT unit with an integrated 2-slice CT scanner (Symbia T E-Cam, Siemens Medical Systems, Erlangen, Germany). The CT acquisition were performed using a tube current modulation system (Care Dose 4D). Parameters used were: tube current of 30 - 60 mAs, slice thickness of 3-5 mm, and tube voltage of 110 kV. Results: Our results show that SPECT dosimetry depends on administered activity and patient’s age and weight. For CT scan, effective dose is affected by tube current (mA), tube potential (kVp), rotation speed, pitch, slice thickness, patient mass, and the exact volume of the patient that is being imaged. Conclusion: For children, 123II-MIBG study with SPECT/CT should be performed using the lowest available voltage and current. A sensible choice of these two parameters used can significantly reduce radiation dose, without any compromise in the quality of the diagnostic information
Nanotechnology in radiation oncology: The need for implantable nano dosimeters for in-vivo real time measurements
Get PDFRapidly advancing technology provides successive generations of irradiation techniques and modalities of cancer treatment in radiation oncology. Most of these techniques are able to deliver higher doses per fraction than the standard 2 Gy per day. The complexity of these new techniques involves hundreds of parameters for the delivery of each beam making quality assurance increasingly demanding. A direct assessment of the "final product", namely the absorbed dose, would be extremely useful if easy to obtain. Thus, a real need exists for dosimeters able to provide direct and real time measurements within the target volume. Nanotechnology is a relatively new field, and in some ways raises new technological aspirations, especially in the field of medical applications for cancer treatment. In this paper we argue the need for an implantable “nano-dosimeter” based on nanotechnology to monitor the delivered dose, combining all the ideal features such a future tool should have for quality assurance in radiation oncology.
Boron neutron capture therapy design calculation of a 3H(p,n) reaction based BSA for brain cancer setup
Get PDFPurpose: Boron neutron capture therapy (BNCT) is a promising technique for the treatment of malignant disease targeting organs of the human body. Monte Carlo simulations were carried out to calculate optimum design parameters of an accelerator based beam shaping assembly (BSA) for BNCT of brain cancer setup.Methods: Epithermal beam of neutrons were obtained through moderation of fast neutrons from 3H(p,n) reaction in a high density polyethylene moderator and a graphite reflector. The dimensions of the moderator and the reflector were optimized through optimization of epithermal / fast neutron intensity ratio as a function of geometric parameters of the setup. Results: The results of our calculation showed the capability of our setup to treat the tumor within 4 cm of the head surface. The calculated peak therapeutic ratio for the setup was found to be 2.15. Conclusion: With further improvement in the polyethylene moderator design and brain phantom irradiation arrangement, the setup capabilities can be improved to reach further deep-seated tumor
Liver lesions in children post-oncologic therapy: Review of case reports and institutional observation
Get PDFPurpose: Focal nodular hyperplasia (FNH), a benign hepatic tumor with ill-defined etiology, has been increasingly reported in children treated for extra-hepatic malignancies. Serial imaging or biopsy may be needed when survivors present with liver lesions. This study aims to review the literature, compare them with our institution’s cohort and propose a less invasive diagnostic imaging modality for FNH utilizing Magnetic resonance imaging (MRI) with gadoxetate disodium. Methods: We reviewed 13 case reports/series published over the last 20 years and compared them to our retrospective review of 16 childhood cancer survivors (CCS) found to have liver lesions on various imaging studies. Several patients underwent biopsy for diagnosis. Results: No specific generalizations could be made in terms of which specific chemotherapeutic agents cause FNH. Seven out of 11 patients underwent radiotherapy and/or hematopoietic stem cell transplant. Additionally, 36% (4/11) had been treated for neuroblastoma. From the literature review, the use of MRI with gadoxetate disodium was difficult to evaluate. Imaging was mainly accomplished using ultrasound, computerized tomography and MRI with gadolinium. The results were often indeterminate and resulted in biopsy in 6 cases in our institution. In contrast, 5 patients underwent initial MRI with gadoxetate disodium, which confirmed the diagnosis of FNH. Conclusion: CCS have an increased risk of developing liver lesions. Consistent with previously published literature, patients exposed to radiotherapy or cytoreductive agents used for hematopoietic stem cell transplants appeared to be at higher risk. A significant proportion (36%, 4/11) of our patients with FNH was previously treated for neuroblastoma. With the introduction of MRI with gadoxetate disodium, imaging may be a viable alternative to biopsy.
Dose verification of intensity modulated radiotherapy in head and neck tumors
Get PDFPurpose: To evaluate the agreement between measured and calculated doses for head and neck tumors using different gamma criteria and to establish quality assurance protocol for the delivery of IMRT in The National Cancer Institute in Cairo. Methods: The dose is calculated for 30 patients using CMS Treatment Planning System. The ionization chamber (0.6 cm3 Farmer type) is used for point dose measurements. The 2D-array (PTW 729) and GafChromic films (EBT2) are used for 2D graphical dose distribution. Four different gamma criteria of dose difference (DD) and distance to agreement (DTA) (3%/3 mm, 3%/5 mm, 4%/4 mm and 5%/5 mm DD / DTA) are selected. These criteria are evaluated while suppressing the dose of 10%, 20% or 30% from dose distribution. Results: Point dose evaluations using the ion chamber ranged from -2.6% to 3.7% (mean and standard deviation of 0.46 ± 1.7). Significant differences are observed between the films and 2D-array for all criteria except the 3%/5 mm criteria (96.89 ± 2.2% vs. 94.81 ± 4.2% (p < 0.01)). Conclusion: Differences may exceed about 3% when the ionization chamber is present in steep dose gradient regions. The present results suggest the gamma criteria of 3%/5 mm as the most suitable criteria for IMRT quality assurance. This gamma criterion of 3%/5 mm favorably exceeds 95% in case of maximum dose while suppressing the dose of 20%.The use of 2D-array can reduce the IMRT QA workload.------------------------------Cite this article as: Elawady RA, Attalla EM, Elshemey WM, Shouman T, Alsayed AA. Dose verification of intensity modulated radiotherapy in head and neck tumors. Int J Cancer Ther Oncol 2014; 2(3):02037. DOI: 10.14319/ijcto.0203.