Showing 16 results for Radiation
K Imandel , I Mobedi , A Mesdaghinia , F Vaezi ,
Volume 56, Issue 2 (4-1998)
Abstract
Wastewaters are one of the most important sources for transmission of pathogenic agents in environment, so they should be disinfected in a manner that their overall qualities become accordant with WHO-guidelines, if it is needed to reus water correctly. Unfortunately, the protozoa and parasitic worm's eggs can not be destroyed by chlorination alone. This experiment was carried out in order to determine the efficiency of the UV-Lamps in inactivation of the Ascaris Lumbericoides-ova which is the most resultant organism among the other nematode eggs. The minimum inhibitory dose of UVR (UVC plus UVB irradiances) for Ascaris-ova complete destruction ascertained to be 420 miliwatts-seconds per square centimeter.
Hadad P, Karimi M,
Volume 60, Issue 1 (4-2002)
Abstract
Xerostomia is one of the disturbing side-effects of the radiotherapy to the head and neck region. Pilocarpine has been approved for the treatmentof this condition in the chronic phase, but its use concurrent with radiation could also be beneficial for prevention or reducing the subsequent radiation-induced xerostomia. We undertook to test this hypothesis in a clinical trial.
Materials and Methods: All 18- to 70-year old patients who were to be irradiated to the head and neck, with both parotid glands in the radiation fields, were eligible for this study. Patients with any medical contraindications for pilocarpine were excluded. Randomization was performed at the start of radiotherapy to either pilocarpine 5 mg three times daily or placebo in a double-blind setting. The drug was started with irradiation and continued until 3 months after the end of radiotherapy. Serum pilocapine levels were measured in a randomly selected number of patients by high-pressure liquid chromatography (HPCL). Xerostomia was evaluated about 6 months after the end of radiation by an analog-scale questionnaire, and the objective grading of xerostomia was recorded by two separate observers.
Results: A total number of 60 patients were randomized into the trial (31 pilocarpine, 29 placebo), mostly with nasopharyngeal carcinomas. Mean parotid dose was 5, 818 cGy. Mean pilocarpine serum level was 14.65 ng/ml. No serous side-effect was observed. Thirty-nine patients were analyzed for xerostomia at a median time of 7 months after radiotherapy, 18 in pilocarpine and 21 in placebo groups (9 patients died and 12 patients did not come back for xerostomia evaluation). Mean subjective xerostomia was 40.3 mm in the pilocarpine group and 57 mm in the placebo group (p= 0.02). Also mean objective xerostomia grade was 2.2 in the pilocarpine group and 2.6 in the placebo group (p= 0.01). Subjective and objective xerostomia results were positively correlated (level 0.01). Age and the parotid dose did not have a significant effect on xerostomia.
Conclusion: Pilocarpine as prescribed in our trial produced the standard serum level required, and no serious side-effect. Compared to polacebo, pilocarpine used with radiotherapy could lead to a diminishment of subsequent radiation-induced xerostomia.
Mojahed Mm, Aghili M, Kazemian A, Farhan F, Izadi Sh,
Volume 66, Issue 11 (2-2009)
Abstract
Background: Chemo-radiotherapy-induced oral mucositis represents a therapeutic challenge frequently encountered in cancer patients. This side effect causes significant morbidity and may delay or interruption of treatment plan, cyclo-oxygenase 2 (COX2) is an inducible enzyme primarily expressed in inflamed and tumoral tissues. COX-2 inhibitors have shown promise to reduce chemoradiation induce toxicities. We conducted a phase III, randomized double blind clinical trial to evaluate the toxicity and efficacy of celecoxib, a selective COX2 inhibitor, administered concurrently with chemoradiation for locally advanced head and neck cancer. Here in we report the first report about the role of COX-2 inhibitor in acute toxicicities.
Methods: Patients with stage III/IV (locally advance) head and neck carcinoma who referred to department of radiation-oncology were eligible. Patients were treated with chemotherapy with cisplatin concurrently with radiation (60-70Gy). Celecoxib (100mg qid) was started at the first day of radiotherapy and was given for a total of 8 weeks. Acute toxicities were evaluated every week by WHO scale.
Results: One hundred twenty two patients were enrolled into the study, (61 patients for each group). In repeated mesurment analysis of variance there is a significant difference in the time of onset of grade II acute toxicities between the two groups The mucositis, dysphagia, epidermitis and oral pain score changed significantly over the typical five weeks in two groups but these changes were more sever in placebo group (p=0.0001). In the analysis of the overall changes in the following laboratory parame-ters: WBC, hemoglobin and platelet showed that these parameters decreased over time in both groups without a significant difference between groups.
Conclusion: The results of these study showed that the use of a COX-2 inhibitor (celecoxib) that is a safe and inexpensive drug may reduce acute toxicities of chemoradiation specially mucositis in head and neck carcinoma.
Ahmadi-Ashtiani Hr, Hekmat-Nazemi N, Rezazadeh Sh, Gholamhoseini B, Baghaei M, Houshang Ehsani A, Rastegar H,
Volume 68, Issue 6 (9-2010)
Abstract
Background: Nowadays skin damages caused by ultraviolet (U.V.) radiation from the sun were increased accordingly necessity for safe and inexpensive protective products for reducing the harmful effects of this ray is unassailable. The antiradical, anti irritation and anti-cancer properties of silymarin make it a suitable option for use in cream formulation to investigate its effect on skin disorders caused by U.V. radiation. In this research effect of local application of a cream containing silymarin in prevention of the harmful effects of U.V. radiation on the guinea pig skin were studied and evaluated by using histopathologic and clinical findings.
Methods: 75 albino guinea pigs were randomly divided into five groups of fifteens. 2cm2 of the back hair was shaven. In the first group no treatment was applied, in the second group vaseline, in group 3 base cream without silymarin extract, in group 4 silymarin extract and in group 5 cream containing silymarin extract were used.
Results: In clinical assessment, skin scaling, skin irregularity, erythema, skin hyperpigmentation, and edema were observed and in histopathological observation epidermal hyper keratosis, hyperpigmentation, exocytosis, acanthosis, chromatin discoloration in nucleus of epidermal squamous cells, perifolliculitis, dermal vascular hyperemia, edema and dermal thickness, infiltration of plasma cell lymphocytes and eosinophyls into dermis were detected. The statistical comparison of group 1 and group 5 shows statistically significant difference in most indices (p<0.01).
Conclusions: Clinical and histopathologic examinations showed that local application of a cream containing silymarin is effective in prevention of skin damage caused by U.V. radiation in guinea pig's skin also the results of the clinical and histopathologic observation in this study confirm the enzymatic results in other researches.
Aghili M, Babaei M, Azmoodeh Ardalan F, Farhan F, Hadad P, Ghanjalikhani M,
Volume 68, Issue 7 (10-2010)
Abstract
Background: Colorectal cancer is the third common cancer world wide and the forth in Iran. Neoadjuvant chemoradiotherapy is the standard treatment for locally advanced rectal cancer. In this study we evaluate the efficacy a cox-2 inhibitor on pathologic response, sphincter preservation and acute toxicity during neoadjuvant chemoradiation.
Methods: Thirty-six patients that have adenocarcinoma of rectum was enrolled (up to 15 cm of anal verge). The patients were undergone Endometrial Ultrasound (EUS), abdomino-pelvic and chest CT for staging. Then received neoadjuvant concurrent chemo radiation (xeloda 825 mg/m2 bid in combination with celecoxib 100 mg qid and 50-50.4Gy/25-28f). Surgery was done 4-8 weeks after chemoradiation. During the chemoradiation the patients was observed for the probable complication one year. Tumor regression grade was reported.
Results: From 36 surgery patients, Total Mesorectal Excision (TME) was done in 30 patients. Pathologic complete response was seen in eight of 30 patients (26.7%). Tumor regression grade was calculated in three and five grade system: in three grade system 17 patients had grade 1 (60.7%), eight patients had grade 2 (28.6%) and three patients had grade 3 (10.7%). In five grade system of tumor regression eight patients had grade 1 (28.6%), nine patients had grade 2 (32.1%), eight patients grade 3 (28.6%), three patients had grade 4 (10.7%). T down staging was 43.3%. N downstaging was 30.8%. No patient had skin reaction or cardio-vascular complication.
Conclusion: Based on our study results, Celecoxib in combination with neoadjuvant chemoradiation is safe and is associated with low complications. This combination can promote pathologic complete response, TRG and T and N downstaging in Rectal adenocarcinoma.
Peiman Haddad , Zhaleh Karimimoghaddam , Farshid Farhan , Mahbod Esfahani , Mahdieh Afkhami , Farnaz Amouzegar-Hashemi,
Volume 71, Issue 11 (2-2014)
Abstract
Background: Colorectal carcinoma is a common malignancy, in treatment of which pelvic radiotherapy plays an important role. But this may lead to azospermia. We designed a study to determine the delivered dose to the testis with thermoluminescence dosimetry (TLD) and compare it to the dose calculated by the Three-dimensional planning software.
Methods: We measured the testicular doses by TLD the TLDs were fixed to the scrotum in six points anteriorly and posteriorly in two random fractions of the radiation course. All patients received a 50-50.4 Gy radiation dose to the pelvis in a prone position with standard fractionation and 3-dimensional planning, through three or four fields. The average dose of the TLD measurements was compared to the average of 6 relevant point doses calculated by the planning software.
Results: In 33 patients with a mean age of 56 years, the mean testis dose of radiation measured by TLD was 3.77 Gy, equal to 7.5% of the total prescribed dose. The mean of point doses calculated by the 3-dimensional planning software was 4.11 Gy, equal to 8.1% of the total prescribed dose. A significant relationship was seen between the position of the inferior edge of the fields and the mean testis dose (P= 0.04). Also body mass index (BMI) was inversely related with the testicular dose (P= 0.049).
Conclusion: In this study, the mean testis dose of radiation was 3.77 Gy, similar to the dose calculated by the planning software (4.11 Gy). This dose could be significantly harmful for spermatogenesis, though low doses of scattered radiation to the testis in fractionated radiotherapy might be followed with better recovery. Based on above findings, careful attention to testicular dose in radiotherapy of rectal cancer for the males desiring continued fertility seems to be required.
Vahid Karami , Mansour Zabihzadeh ,
Volume 74, Issue 7 (10-2016)
Abstract
Discovery of x-ray and using of it for medical imaging have produced tremendous outcomes for diagnosis and treatment of diseases. More than 10 million diagnostic radiological procedures and 100,000 nuclear medicine exams are being performed daily around the world. According to the national commission on radiological protection and measurements (NCRP)-report 160, medical x-ray is contribute to approximately 95% of all radiological examinations that is responsible for 74% of the collective dose to the US population. Despite of unique benefits of ionizing radiations, in the field of radiation protection, they are associated with potential risks such as cancer and genetically abnormalities. The cancer risk attributable to diagnostic radiology is estimated about 0.6% to 3%. It is estimated that the radiation dose from diagnostic x-ray procedures are annually responsible for 7,587 and 5,695 cases of radiation induced cancer in the population of Japan and US, respectively. Although the radiation dose associated with most radiological procedures are very low, but rapid increasing use of radiography procedures during two past decades have been concerned due to the cancer risk associated with ionizing radiations. On the base of linear no-threshold (LNT) model of dose-response curve, any level of exposure is dangerous. Deoxyribonucleic acid (DNA) is the main target of ionizing radiation. For radiological exposure with low dose, the stochastic effects such as genetic damages and leukemia are concerned. According to the recommendations of the radiation protection regulatory organizations, radiological procedure must be done with respect to social and economic factors in which exposure of patient and population kept as low as reasonable and achievable. Hence, prescription of a radiological test is acceptable only when its advantages are higher than its damages. Optimizing the different parameters such as: collimating the primary beam field to the area of diagnostic interest, exposure conditions (high kVp and low mAs), projections, exposure time and shielding can reduce the patients' exposure besides the saving of image quality. Following the radiation protection guidelines can considerably decrease the exposure risks.
Ayoub Amirnia, Parinaz Mehnati , Nasrollah Jabbari ,
Volume 75, Issue 2 (5-2017)
Abstract
Background: Due to the presence of radiosensitive organs in the abdominopelvic region and increasing the number of requests for CT scan examinations, concerns about increasing radiation doses in patients has been greatly elevated. Therefore, the goal of this study was to determine the absorbed dose of radiosensitive organs and the effective dose in patients underwent abdominopelvic CT scan using ImPACT CT patient dosimetry Calculator (version 1.0.4, Imaging Performance Assessment on Computed Tomography, www.impactscan.org).
Methods: This prospective cross-sectional study was conducted in Imam Reza Hospital from November to February 2015 February 2015 in the Imam Reza Hospital, in Urmia, Iran. The demographic and dosimetric information of 100 patients who underwent abdominopelvic CT scan in a 6-slice CT scanner were obtained through the data collection forms. The demographic data of the patients included age, weight, gender, and BMI. The dosimetric parameters included pitch value, CT dose volume index (CTDIvol), dose-length product (DLP), tube voltage, tube current, exposure time, collimation size, scan length, and scan time. To determine the absorbed dose of radiosensitive organs and also the effective dose in patients, ImPACT CT patient dosimetry calculator was used.
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Results: The results of this study demonstrated that the mean and standard deviation (SD) of patients' effective dose in abdominopelvic CT scan was 4.927±0.164 mSv. The bladder in both genders had the greatest mean organ dose, which was 64.71±17.15 mGy for men and 77.56±18.48 mGy for women (P<0.001).
Conclusion: The effective dose values of this examination are in the same range as previous studies, as well as International Commission on Radiological Protection (ICRP) recommendations. However, the radiation dose from CT scan has the largest contribution to the medical imaging. According to the ALARA principle, it is recommended that the scan parameters, especially mAs, should be chosen so that the patient dose is minimum, and the image quality is maximum. Furthermore, other imaging modalities are used as an alternative to the CT scan.
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Vahid Karami , Mansour Zabihzadeh , Nasim Shams , Mehrdad Gholami ,
Volume 75, Issue 2 (5-2017)
Abstract
Background: Anode heel effect refers to reduction of radiation intensity in the anode side of X-ray tube. This variation in radiation intensity across the anode-cathode of X-ray tube can be benefited for decrease radiation exposure in some radiological examinations. The aim of this study was to evaluate the effect of anode heel orientation on the radiation dose received by the testes in male patients undergoing pelvic radiography.
Methods: This is a cross-sectional study, conducted at one of the teaching hospitals of Ahvaz, Jundishapur University of Medical Science Ahvaz, Iran, from September 2015 to March 2016. In order to measure the profile of radiation intensity variation, 13 paired sets of high radiosensitive cylindrical lithium fluoride thermo-luminescent dosimeters (TLD) aligned on the cathode-anode central axis upon the table and then irradiated using routine exposure parameters. The anode of X-ray tube was positioned toward the feet for 40 patients and toward the head for 39 patients undergoing pelvic radiography. For measure the entrance skin dose (ESD), 8 TLD chips were located on the central point of the radiation field and 5 TLDs were located on the testes position to measure the dose received.
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Results: Radiation intensity profile showed that radiation intensity decrease from the cathode to the anode side. Discrepancy of radiation intensity on central axis of cathode-anode was calculated about 35%. The radiation dose received by the testes was 26.74% lower for patients the anode directed toward the feet, compared to the patients in which the anode directed toward the head (FTC: 1.260±0.296 mGy, FTA: 0.923±0.167 mGy, P<0.05). There was no meaningful difference for the measured ESD of pelvis between two groups of patients (FTC: 1.256±0.315 mGy, FTA: 1.195±0.205 mGy, P=0.788).
Conclusion: In pelvic radiography, positioning of testes directed to the anode of X-ray tube can decrease the receive dose.
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Daryoush Khorramian , Soroush Sistani , Amin Banaei , Salar Bijari ,
Volume 75, Issue 7 (10-2017)
Abstract
Background: There are several techniques for reducing the delivered dose from CT (Computed tomography) scanning such as the automatic exposure control (AEC). This technique modulates the tube current regarding the patient size and weight. The aim of this study was to estimate the effect of the AEC on the radiosensitive organs effective doses in women undergoing chest CT scanning.
Methods: This study was a cross-sectional, analytical and quantitative study that was performed during 3 months in the imaging section of the Firoozgar educational and therapeutic hospital (belonging to Shahid Beheshti University of Medical Sciences) in the spring of 2017. CT scan exposure parameters were gathered and registered for 54 women undergoing chest CT scan. 25 of these scans were performed using AEC system and 29 of them were performed without using AEC. CT dose indexes in the center and peripheral regions of the standard phantom were calculated using the exposure parameters. Weighted CT dose index was also calculated and effective organ doses were obtained using CT-Expo software, version 2 (Medizinische Hochschule, Hannover, Germany) for two mentioned groups. In addition, noise was measured for these two groups as an image quality parameter.
Results: Calculated weighted CT dose indexes were 9.94 mGy and 12.46 mGy using AEC system and without using AEC, respectively. The calculated effective doses were equal to 5.4 mSv and 6.3 mSv using AEC and without using AEC, respectively. Maximum organ effective doses were 15, 14, 14 and 14 mSv for breast, esophagus, lung and thymus respectively in the non-using AEC system imaging technique.
Conclusion: Our measurements indicated a decrease about 15% in weighted CT dose index (from 12.46 to 9.94 mGy) using AEC system. Beside of this fact, the noise increased about 11.3% (from 4.2 to 4.74) using AEC system. So, it can be said that using of AEC was an effective way for dose reduction in women undergoing chest CT scanning, and the additional noise was in the acceptable range.
Vahid Karami,
Volume 76, Issue 2 (5-2018)
Abstract
[Available in Persian]
Amin Banaei, Bijan Hashemi, Mohsen Bakhshandeh, Bahram Mofid,
Volume 77, Issue 2 (5-2019)
Abstract
Background: Intensity-modulated radiotherapy (IMRT) is one of the most usable methods in prostate radiotherapy that is used with different techniques. The aim of this study was to evaluate and compare the dosimetric and radiobiological effects of prostate IMRT techniques regarding to joint volume between the target tissue and organs at risk as a patients anatomical parameter.
Methods: This research was a cross-sectional, analytical, and quantitative study that was carried out from April 2016 to June 2018 at the radiotherapy and oncology center of Shoheday-e-Tajrish Hospital and Medical Physics Department of Tarbiat Modarres University Tehran, Iran. Four various prostate IMRT techniques (9, 7 and 5 fields and automatic) were planned on 63 prostate cancer patients CT scans. Radiobiological effects were calculated using Relative Seriality model for the organs at risk (bladder and rectum) and target tissue. Results of mentioned prostate IMRT techniques were compared based on the patient’s anatomical parameter.
Results: For the patients with joint volumes ranged from 0 to 15%, statistical differences were not observed among various IMRT techniques. The tumor control probability and complication free tumor control probability values decreased as a function of joint volume. The normal tissue complication probability value increased as a function of joint volume. The 9 and 7 fields IMRT techniques had not any significant differences (P=0.06) in all of the joint volume ranges. In patients with the joint volumes higher than 30%, the 9 and 7 fields techniques showed significantly better radiobiological values in comparison with 5 fields and automatic techniques (P=0.009).
Conclusion: In the patients with lower percentage of joint volume, all the mentioned prostate IMRT techniques showed same radiobiological effects; however, in the patients with higher joint volume percentages (> 30%), the 9 and 7 fields techniques have better results. It is proposed to use the 7 fields technique instead of the 9 fields technique, especially in prostate cancer cases with high uncertainty in patients’ setup.
Mohsen Shoja, Mohadese Soleimani, Maryam Ameriyan , Niloufar Asbaghipour , Peyman Hejazi Hejazi ,
Volume 77, Issue 2 (5-2019)
Abstract
Background: Today, with the increasing use of ionizing radiation like X-rays in diagnosis and treatment of diseases, the risk of fetal exposure in pregnant women also increases. Therefore, protecting pregnant women from ionizing radiation is essential and is considered as the standard criterion for Medical Radiation Center. So the aim of this study was to investigate the observance of protective principles and 10-day rule in imaging of susceptible women.
Methods: This cross-sectional study was carried out at the Radiography Centers of Semnan University of Medical Sciences, Iran, from July 2017 to September 2017. First, patients who were under radiography, were asked about the knowledge of the radiographers about the 10-day rule and radiation protection. Then a questionnaire with 12 questions was given to the radiographers in radiology and CT scan center. Finally, the existence of protection guidelines for pregnant women was determined by asking manager and checking at the moment.
Results: The patient's question about pregnancy failed about 19%, which did not have a significant relationship with patients' singleness (P=0.0004). Also the mean scores for the knowledge of radiographers about radiation protection were 14.21±0.96, which did not have a significant relationship with their work record and place of employment and their educational level (P=0.09). On the other hand, in half of the radiography centers, the written radiation protection guidelines were not available.
Conclusion: Principles of radiation protection and 10-day rule for radiography of women who were prone to pregnancy were desirable but due to importance of radiation protection, the rules should be more carefully implemented.
Elham Hoseinnezhad Zarghani, Ghazale Geraily, Mahbod Esfahani, Mostafa Farzin,
Volume 78, Issue 7 (10-2020)
Abstract
Background: Total body irradiation (TBI) is a technique that is commonly used as a part of the patient conditioning regimen before the bone marrow transplant (BMT). The purpose of this study is to introduce and implement a reasonable TBI technique on the human-like phantom in Imam Khomeini Hospital in Tehran.
Methods: The present experimental study was conducted from October 2016 to November 2017 to implement the TBI technique at the Cancer Institute of Imam Khomeini Hospital in Tehran. For this purpose, percentage depth dose, and dose rate were measured in TBI condition (i.e. SSD=310 cm, field size=40×40 cm2, gantry angle=90°, and collimator angle 45°) in homogeneous phantom. Gafchromic EBT3 films were used to measure the absorbed dose in different areas of the human like phantom at the levels of head, neck, thyroid, lung, umbilicus, pelvic, thigh, knee and leg. Phantom irradiation was performed in parallel opposed anterior-posterior geometry using an 18MV photon beam produced by Varian 2100C/D. Cerrobend blocks were used for lung protection. After analyzing the exposed films with Image J software, the dose uniformity was calculated.
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Results: Dose distribution uniformity was acquired in the order of -1.01% to +11.82% relative to the prescribed dose at the umbilicus. The difference between the calculated and measured dose at the umbilicus level was -2.73%. The radiation absorbed dose to the lung with blocks was 127.53cGy in one fraction which resulted in 756.18cGy in six fractions.
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Conclusion: The implemented technique, obtained the acceptable ±10% dose uniformity in most of the body regions. The dosing accuracy was within the acceptable range. The lungs¢ dose was reduced to the desired level using lung shields. This technique is a simple and cost-effective method that does not require complicated dosimetric techniques. Regarding the obtained results, the proposed technique has the necessary conditions for implementation in Imam Khomeini hospital in Tehran.
Arezoo Kazemzadeh, Iraj Abedi, Alireza Amouheidari, Atefeh Shirvany,
Volume 78, Issue 9 (12-2020)
Abstract
Background: To date, different kinds of treatment methods have been proposed for radiotherapy of cancer patients. Choosing the kind of treatment method affects the quality of the patient's treatment. This study aims to investigate the effect of the number of radiation treatment sessions on the dose received by the patient and the distribution of tumor dose and dose received by organs at risk in breast cancer radiation therapy. These results help us to select the appropriate treatment schedules for the treatment of left breast patients.
Methods: This prospective cross-sectional study was performed on the treatment plans of 35 patients with left breast cancer who referred to Isfahan Milad Hospital between July 2019 and April 2020. They were candidates for left breast radiation therapy. Also, these patients had no history of surgery or chemotherapy, and no supraclavicular or axillary lymph nodes were involved. Patients were treated with a conventional fraction regimen (CF) or hypofractionated (HF) treatment schedule. Different dosimetry parameters for the target and organ at risks such as conformity index, homogeneity index and mean dose were obtained from the dose-volume histogram plot. Finally, the results of both plans were compared with each other.
Results: The data obtained from this study indicate a decrease in the average dose of all organs in the hypo fractionated regimens compared to conventional plans. The differences between two plans were statistically significant for tumor, lung, and skin (P=0.0). Moreover, the maximum dose for the skin was also reduced when hypofractionated regimens were used. However, the values of the homogeneity index and conformity index of tumor in the two methods did not show a significant difference (P were 0.99 and 0.86, respectively).
Conclusion: In general, the results of the current study indicate that the hypofractionated regimen leads to a reduction in dosimetric factors compared to conventional fraction plans. It seems that this method can be used as an alternative treatment plan for breast cancer radiation therapy due to the reduced duration of the treatment period. |
Seyed Hamed Jafari, Hajar Zahedi Mehr , Banafsheh Zeinali-Rafsanjani , Sara Haseli, Mahdi Saeedi-Moghadam ,
Volume 80, Issue 6 (9-2022)
Abstract
Background: The image quality is paramount in interpreting the hepatic dynamic CT scan. A poor quality image results in repeating the procedure, which is very time-consuming for the patient and staff, and besides, it is not cost-efficient. This study intended to determine the correlation between image quality and the Hounsfield unit (HU) of the liver and its vessels in the arterial and venous phase to define the acceptable range of HUs for hepatic CT images.
Methods: The image quality of 146 dynamic CT scans was assessed by qualitative and quantitative methods at Namazi Hospital of Shiraz University of Medical Sciences from September 2019 to August 2021. Two radiologists performed the qualitative evaluation. They categorized the image qualities into three groups; poor, acceptable, and high quality. For quantitative assessment of image quality, the Hounsfield unit of the aorta, hepatic vein, main portal vein, right anterior, right posterior, and left lateral lobe of the liver were evaluated in both arterial and venous phases.
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Results: According to the results of the qualitative evaluation of image quality, 59.6%, 17.8%, and 22.6% of triphasic CT scans had good, acceptable, and poor quality, respectively. There was a significant relationship between image quality and Hounsfield units of all ROIs in the arterial phase (P<0.005). Also, a significant relationship was observed between the Hounsfield units of the portal vein right on the anterior and posterior segments of the liver (P<0.03) in the venous phase.
Conclusion: In a high quality triphasic CT scan, the Hounsfield unit of different parts in the arterial phase should be as follows: aorta 310±78, portal vein 150±40, hepatic vein 44±7, right posterior and anterior and left lateral segments of liver 77±11, 77±7 and 78±12. Hounsfield units of the portal vein, hepatic vein, and right posterior and anterior segments of the liver in the venous phase should be 155±27, 167±30, 111±19, and 112±16, respectively.
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