seyed rabi mahdavi

The considerable growth of 3D printing technology in recent years has led to the application of this emerging technology in many medical fields, in which recently performed studies have shown the special importance of this technology which can enhance the results of the treatment method. Since, surgery is one of the main modalities to treat patients, the advent of 3D printing technology in surgery and the creation of different patient organs with 3D printers, improve the surgeon's performance. Hence, the accuracy and quality of the surgery can be enhanced. The aim of this study was to review the current statues and the applications of the 3D printing technology in surgery.

By searching the indexed articles in Persian and Latin databases, Scopus, PubMed, Science direct, Scholar, 34 studies were reviewed.

3D printing applications in surgery: Generally, the ability to generate a physical object with complex structures from a digital model has been introduced as the 3D printing technology which offers many advantages over the traditional manufacturing. The most important advantage of 3D printing technology is the ability to produce objects based on individual needs in which can reduce the costs of their production. Furthermore, complex preoperative procedures can be practiced. In other words, 3D printed models allow physicians to become familiar with medical procedures which possible problems created during the operation, can be identified before the operation. This modern technology generally includes three main steps to generate 3D objects from imaging data. The first step is the acquisition of image data. Then, the interest region is extracted which is termed as the segmentation. Finally, the digital data is transferred to the 3D printers to produce the 3D object.  For 3D model production, printer selection highly depends on speed, accuracy, cost, and availability of the printing materials. Recent advances in 3D printing technology have made it possible to use various biocompatible materials such as titanium and degradable polyesters to produce 3D models. Complex surgeries require more precise visual understanding before the surgery to ensure about the success of the treatment. In this regard, 3D printing technology can be a promising way to produce faster and cheaper models. In addition, this modern technology enables producers to produce highly specialized products for a wide range of patient organs. Applying a physical model results in better performance and greater visual perception about the desired treatment area, which can significantly reduce the side effects during surgery. Since a large contribution of the surgical process can be performed outside the operating room hence, 3D printed models can reduce the operation time. In fact, before the operation, surgeons will have enough time to make decisions, evaluate solutions and focus on other key elements during the operation. So, based on the basic role of 3D printing technology in surgery, the purpose of the present review is to investigate the current state of 3D printing technology and its clinical application in surgery for the construction of various 3D organs via medical imaging data. In this paper, some applications such as maxillofacial, spinal, liver, etc., are briefly discussed. Maxilla-facial and cranial facial reconstruction are the complex procedure which have been one of the first and most proven applications of 3D printing in the field of surgery to correct the facial deformities after the tumor resection. In this method with the application of 3D printers, at first, a 3D model of the desired anatomy is prepared to reduce a significant amount of time for linking the titanium plates to transplant adjacent bones (while the patient is anesthetized). Also, the production of titanium implants using the 3D printers will result in a very precise fit with the target tissue, the risks of maxillofacial surgery can be reduced.The use of 3D printing applications before or during complex surgeries like congenital heart defects has been reported in several studies. Since, acquiring to the real anatomical structures in patients with complex congenital defects, are sometimes unpredictable, treatment planning and surgical decision-making require a thorough understanding of three-dimensional anatomy. Therefore, the 3D printing technique, as a widely used method in all medical fields can overcome the defects of common preoperative imaging, especially in cardiovascular surgery.The other application of 3D printing technology includes spinal surgery in which due to the complex anatomy of the spine and the delicate nature of the surrounding structures, 3D printers will improve preoperative planning and increase the accuracy during the surgery.Liver surgery can be another suitable candidate for performing 3D printing technology to create 3D printing models. The two main applications of 3D printing technology in this field include training or necessary planning for surgery and liver functional cell printing through bio-printing technology that can be used in the study of liver disease and pharmaceutical research.Renal tumor resection is the other example of 3D printing applications in which 3D models have an exclusive role to enhance the accuracy of renal surgery. The 3D printed models can accurately display three-dimensional spatial relationships between different anatomical and pathological structures. Three-dimensional printed kidney models may also facilitate interdisciplinary communication and decision-making about the management of patients undergoing renal surgery.  In the field of renal surgeries, employing of 3D printed models plays a specific performance to train young surgeons which consequently increases the practical skills of surgeons which can accurately visualize the anatomical and morphological relationship compared to volumetric imaging.The obtained results of performed studies in the field of 3D printing show the potential significance of this technology in surgery which can lead to improvement of therapeutic outcomes. Since the printed models by 3D printing technology have an appropriate fit to the anatomy, the use of these models can reduce the associated errors during surgery.It is worth noting that despite the valuable advantages of this technology, some disadvantages such as limited printing size and costly printing process can be discussed which many studies try to address the deficiency of 3D printing technology in clinical applications. The cost of 3D printed models varies according to the type of performed printing method and applicable software which requires specialized users. The main mentioned costs for 3D model creation include hardware, software, and printed materials. In the future, the production costs of 3D models would be likely reduced in which the use of 3D models would become more traditional in common clinical operation. The 3D printed physical models are based on medical imaging which are prone to errors during the imaging procedures. Hence, increasing the accuracy of creating printed models requires improving the clinical imaging methods. Generally, with the advances in this modern technology, faster, cheaper, and more accurate models can be produced.

Breast cancer is a fatal disease and the leading cause of mortality in women. Radiofrequency hyperthermia is an approach to the treatment of cancer cells through increasing their temperature. The present study aimed to investigate breast tumor ablation via radiofrequency hyperthermia in the presence and non-presence states of magnetite nanoparticles and assess the effects of magnetite nanoparticles on breast cancer treatment in hyperthermia.

Radius hemisphere geometry (5 cm) was designed, which was similar to an actual breast based on the fat tissues, glandular tissues as a semi-oval embedded in the hemisphere, and a radius sphere (1 cm) as a tumor region inside. After utilization in a three-dimensional printer, each layer of the phantom was filled with a proper combination of oil-gelatin with similar dielectric and thermal properties to an actual breast. To evaluate the effects of the magnetite nanoparticles, three weights of the magnetite were added to the tumor region (0.01, 0.05, and 0.1 g). Finally, the phantom was placed in a radiofrequency device with the frequency of 13.56 MHz.

Temperature differences were measured at four different points of the phantom. The power and time in the treatment were estimated at 40 watts and five minutes, respectively. The temperature and specific absorption rate plots were obtained for all the states in several graphs for five minutes.The results showed that the heat generation with the utilization of the magnetite state was higher by approximately 2.5-7˚C compared to the state without magnetite. Furthermore, the temperature of 0.05 gram of magnetite indicated that without causing damage in the healthy tissues, the entire tumor region could attain adequate heat uniformly (6.1-6.4˚C).

Therefore, it could be concluded that 0.05 gram of magnetite could cause ablation in the entire tumor region.

This study aims to investigate the influence of background activity variation on image quantification in differently reconstructed PET/CT images.
Measurements were performed on a Discovery-690 PET/CT scanner using a custom-built NEMA-like phantom. A background activity level of 5.3 and 2.6 kBq/ml 18F-FDG were applied. Images were reconstructed employing four different reconstruction algorithms: HD (OSEM with no PSF or TOF), PSF only, TOF only, and TOFPSF, with Gaussian filters of 3 and 6.4 mm in FWHM. SUVmax and SUVpeak were obtained and used as cut-off thresholding; Metabolic Tumor Volume (MTV) and Total Lesion Glycolysis (TLG) were measured. The volume recovery coefficients (VRCs), the relative percent error (ΔMTV), and Dice similarity coefficient were assessed with respect to true values.
SUVmax and SUVpeak decreased and MTV increased as function of increasing the background dose. The most differences occur in smaller volumes with 3-mm filter; Non-TOF and Non-PSF reconstruction methods were more sensitive to increasing the background activity in the smaller and larger volumes, respectively. The TLG values were affected in the small lesions (decrease up to 12%). In a range of target volumes, differences between the mean ΔMTV in the high and low background dose varied from -11.8% to 7.2% using SUVmax and from 2.1% to 7.6% using SUVpeak inter reconstruction methods.
The effect of the background activity variation on SUV-based quantification in small lesion was more noticeable than large lesion. The HD and TOFPSF algorithms had the lowest and the highest sensitivity to background activity, respectively.

Siliconeprosthetic implants are commonlyutilizedfor tissue replacement and breast augmentation after mastectomy. On the other hand, some patients require adjuvant radiotherapy in order to preventlocal-regional recurrence and increment ofthe overall survival. In case of recurrence, the radiation oncologist might have to irradiate the prosthesis.The aim of this study was to evaluate the effect of silicone prosthesis on photon dose distribution in breast radiotherapy.
The experimental dosimetry was performed using theprosthetic breast phantom and the female-equivalent mathematical chest phantom. A Computerized Tomographybased treatment planning was performedusing a phantom and by CorePlan Treatment Planning System (TPS). For measuring the absorbed dose, thermoluminescent dosimeter(TLD) chips (GR-207A) were used. Multiple irradiations were completed for all the TLD positions, and the dose absorbed by the TLDs was read by a lighttelemetry (LTM) reader.
Statistical comparisons were performed between the absorbed dosesassessed by the TLDs and the TPS calculations forthe same sites. Our initial resultsdemonstratedanacceptable agreement (P=0.064) between the treatment planning data and the measurements. The mean difference between the TPS and TLD resultswas 1.99%.The obtained findings showed that radiotherapy is compatible withsilicone gel prosthesis.
It could be concludedthat the siliconbreast prosthesis has no clinicallysignificant effectondistribution of a 6 MV photon beam for reconstructed breasts.

The accurate dose delivery in intraoperative radiotherapy (IORT) tightly depends on the precision of measured dose by the ion chamber. Output factor (OF) measurement of dedicated intraoperative electron radiotherapy (IOERT) accelerators using ion chamber faces some technical challenges including determination of Ksat.
The goal was to evaluate the performance of ethanol chlorobenzene (ECB) dosimeter in measuring the OF of intraoperative electron beam and to compare the results to those of ionometric dosimetry and Monte Carlo simulation. Consequemtly we determined the Ksat of employed ion chamber through comparison of the ECB response to ion chamber.
LIAC dedicated accelerator (LIAC Sordina SpA, Italy) was used for irradiation. To calculate the Ksat, ECB and Advanced Markus chamber were placed at the depth of maximum dose for different energies of LIAC accelerator. Then, Ksat was calculated through comparison of the obtained results. To measure the OF of electron beam, ECB was placed at the depth of maximum dose for each combination of energy/applicator size, and the absorbed dose was determined. Obtained results were compared to those of Advanced Markus chamber and Monte Carlo simulation.
The results of Ksat measurement showed that there is a very good agreement between the practically obtained Ksat and theoretical values determined by Laitano formalism at different energies (the maximum difference between the results was lower than 1%). The results of ECB OF measurement were in accordance to the results of ionometric dosimetry and Monte Carlo simulation (the maximum difference between the results was about 1.5% and 1.7%, respectively).
Based on the results, it may be concluded that the ECB dosimeter could be considered as an accurate tool for both OF measurement of intraoperative electron beam and cross calibration of employed ion chambers for absolute dosimetry (determination of the Ksat).

Background and Dose calculations in trachea HDR brachytherapy treatment planning systems are greatly based on TG-43 protocol in which, all materials including air inside trachea are treated the same as water. The aim of this study was to survey the effect of air on dose calculations of Flexiplan treatment planning system in trachea HDR brachytherapy.
To evaluate the effect of air inhomogeneity, a neck-equivalent plexiglass cylindrical phantom was used. Dose measurement was carried out by EDR2 film. Treatment planning and irradiation were performed using Flexiplan software and Flexitron brachytherapy system, respectively.
The results showed that considering the air inside trachea as water increases the absorbed dose by 12% which can lead to increment of patient dose.
A significant difference was seen between dosimetry results in the two conditions. Therefore, taking the air similar to water has a considerable effect on dose calculations of trachea HDR brachytherapy and accuracy of treatment plan performed.

Background and Beam shaper is a type of applicator used in conjunction with the intraoperative electron radiotherapy. This study aimed at quantitative evaluation of the photon contamination of this applicator using Monte Carlo simulation.
In this experimental study, at first the head of LIAC accelerator was simulated along with the beam shaper applicator using MCNPX Monte Carlo code. Validity of the simulated model was evaluated by comparing the percentage depth dose curves obtained by Monte Carlo simulation and practical dosimetry. Finally, the photon contamination at different clinical field sizes and electron energies was quantitatively determined.
The results showed that by increase in field size, the photon contamination of the beam shaper applicator was considerably decreased. Furthermore, increment of electron energy could increase the photon contamination.
Increasing the photon contamination at the phantom surface by increment of electron energy and decrement of field size can be attributed to increasing the probability of electron interaction with the steel blades of the beam shaper and production of bremsstrahlung radiation at higher energies. Due to the photon contamination, employing the beam shaper applicator can increase the surface dose.

With the development of science and technology in the medical field and need more than ever to accuracy and quality of treatment has been causer increase different radiotherapy methods. Almost the past two decade’s intraoperative radiation therapy (IORT) as one of the new techniques used to treat cancer patients. One of the problems with this method is obtaining accurate dosimetry, because neither before nor after surgery ray images taken from the area of patient data do not match exactly. Therefore, dosimetric characteristics for intraoperative dedicated radiation therapy accelerators in comparison of conventional accelerators are difficult. The main objective of this study was to investigate the LIAC head a light and portable intraoperative radiation therapy accelerator and dosimetry calculate its features. For this purpose, the LIAC head was simulated using Monte Carlo (MCNP). Then the percentage depth dose curves obtained for reference applicator (10 cm) in all accelerator energies using experimental measurements, simulation model was validated. All experimental measurements were done by 12MeV models of LIAC accelerator. Finally, some dosimetric parameters such as maximum absorbed dose (Dm), maximum depth dose (dm), R50, practical range (Rp), dose profile and other dosimetric parameters evaluated for reference applicator in the all LIAC electron beam energies.The results of this work show that the LIAC accelerator is designed for intraoperative radiation therapy method.

In this study, we aimed to calculate dose enhancement factor (DEF) for gold (Au) and iron (Fe) nanoparticles (NPs) in brachytherapy and teletherapy, using Monte Carlo (MC) method. In this study, a new algorithm was introduced to calculate dose enhancement by AuNPs and FeNPs for Iridium-192 (Ir-192) brachytherapy and Cobalt-60 (Co-60) teletherapy sources, using the MC method. In this algorithm, the semi-random distribution of NPs was used instead of the regular distribution. Diameters were assumed to be 15, 30, and 100 nm in brachytherapy and 15 and 30 nm in teletherapy. Monte Carlo MCNP4C code was used for simulations, and NP density values were 0.107 mg/ml and 0.112 mg/ml in brachytherapy and teletherapy, respectively. AuNPs significantly enhanced the radiation dose in brachytherapy (approximately 60%), and 100 nm diameter NPs showed the most uniform dose distribution. AuNPs had an insignificant effect on teletherapy radiation field, with a dose enhancement ratio of 3% (about the calculation uncertainty) or less. In addition, FeNPs had an insignificant effect on both brachytherapy and teletherapy radiation fields. FeNPs dose enhancement was 3% in brachytherapy and 6% (about the calculation uncertainty) or less in teletherapy. It can be concluded that AuNPs can significantly increase the absorbed dose in brachytherapy; however, FeNPs do not have a noticeable effect on the absorbed dose

In this study, we investigated the combined effect of 2-Methoxyestradiol (2ME2) and 60Co on the cytogenetic damage of iododeoxyuridine (IUdR) in the spheroid model of U87MG glioblastoma cancer cell lines by alkaline comet assay. U87MG cells were cultured as spheroids with diameters of 350 μm. As control, the spheroids of one plate were not treated. Other cultures were pretreated with 2ME2 (250 μM) for one volume doubling time (1 VDT). After this time, the subsequent treatments were performed according to the following groups: 1. Vehicle (this sample was not treated in the 2nd VDT) 2. Treated with 2ME2 (250 μM) for 1 VDT 3. Treated simultaneously with 2ME2 (250 μM) and IUdR (1 μM) for 1 VDT 4. Treated with 2ME2 (250 μM) for 1 VDT then irradiated with 60Co (2 Gy) 5. Treated simultaneously with 2ME2 (250 μM) and IUdR (1 μM) for 1 VDT then irradiated with 60Co (2 Gy) Then the DNA damage was evaluated using the alkaline comet assay method. The results showed that 2ME2 in combination with gamma irradiation of 60Co significantly (p<0.001) increased the DNA damage by IUdR as compared to the control group. Thus the combination of these two agents increased the cytogenetic effects of IUdR in the spheroid culture model of U87MG glioblastoma cell lines. By inhibiting the HIF-1α protein and preventing the G0 phase arrest, 2ME2 causes an increased progression into S phase and increases the IUdR absorption. Then the DNA damage in the spheroid cells increases as the uptake of IUdR is increased. These results suggest that the combined use of 2ME2 and 60Co can increase the radiosensitization effect of IUdR.