Radiation dose from cone beam computed tomography for image-guided radiation therapy

PURPOSE: To perform a comprehensive study on organ absorbed doses and effective doses from cone beam computed tomography (CBCT) for three different treatment sites. METHODS AND MATERIALS: An extensive set of dosimetric measurements were performed using a widely used CBCT system, the On-Board Imager (OBI). Measurements were performed using a female anthropomorphic phantom with thermoluminescent dosimeters (TLD). The effective doses to the body and the absorbed doses to 26 organs were reported using two different technical settings, namely, the standard mode and the low-dose mode. The measurements were repeated for three different scan sites: head and neck, chest, and pelvis. Comparisons of patient doses as well as image quality were performed among the standard mode CBCT, low-dose mode CBCT, and fan beam CT. RESULTS: The mean skin doses from standard mode CBCT to head and neck, chest and pelvis were 6.7, 6.4, and 5.4 cGy per scan, respectively. The effective doses to the body from standard mode CBCT for imaging of head and neck, chest, and pelvis were 10.3, 23.7, and 22.7 mSv per scan, respectively. Patient doses from low-dose mode CBCT were approximately one fifth of those from standard mode CBCT. CONCLUSIONS: Patient position verification by standard mode CBCT acquired by OBI on a daily basis could increase the secondary cancer risk by up to 2% to 4%. Therefore lower mAs settings for daily CBCT should be considered, especially when bony anatomy is the main interest.     

Radiation therapy for muscle-invasive bladder cancer: treatment planning and delivery

Radiation therapy allows organ preservation therapy in selected patients with muscle invasive bladder cancer. This review sets out to explore the role of radiation therapy in the management of muscle invasive bladder cancer. It describes and assesses the potential benefits provided by technological advances in radiation delivery in optimizing the therapeutic ratio.     

Alternative methods for intensity-modulated radiation therapy inverse planning and dose delivery

A large number of IMRT systems are currently being marketed. Many of these systems appear to be unique, and manufacturers often emphasize design differences as they argue the merits of their particular approach. This paper focuses on highlighting the underlying feature that is intrinsically part of all IMRT systems. On the other hand, major differences often appear at the implementation stage for dose delivery. Such variations are evident because each manufacturer has a unique approach to balancing the issues of treatment time, leakage radiation reaching the patient's total body, aperture approximation of the ideal intensity maps, increasing the angles of approach for the treatment fields, integration of on-line imaging, selection of treatment distance, availability of different photon energies, and overall system complexity (i.e., cost). How these different issues are handled in the process of system design affects the relative advantages and disadvantages that appear in the final product. This paper takes the approach of dividing the various IMRT methods into categories that are divided roughly along the lines of the technique used during dose delivery to approximate the intensity patterns. Other features of each system are included under these sub-sections.     

Radiation dose enhancement therapy with iodine in rabbit VX-2 brain tumors

Loading tissue with iodine enhances the radiation dose absorbed from low energy X-rays. In order to test whether this is a useful procedure for treating brain tumors, we infused radiographic contrast media into rabbits carrying VX-2 brain tumors and delivered 15 Gy of 120 kVp X-rays in 3 fractions to the tumor. From CT scans we estimated that the dose enhancement was approximately 30%. The median survival times, after tumor detection on CT, of untreated rabbits, treated with radiation alone, and treated with radiation plus contrast media were 3, 25.5, 38.5 days, respectively. The repeated infusion of contrast media, 3.5 g of iodine per kg of body weight, did not affect kidney function as measured by serum creatinine levels. This method of enhancing radiation dose in brain tumors therefore appears promising.     

Radiation dose escalation combined with hormone therapy improves outcome in localised prostate cancer

We present the impact of systematic radiation dose escalation from 64 Gy to 66 Gy to 70 Gy on the outcome after radiation therapy (RT) alone or combined with hormonal treatment (HT) in a series of 494 consecutive localised prostate cancer patients treated during 1990-1999. Prognostic factors for prostate-specific antigen (PSA) failure, overall survival (OS) and prostate cancer specific survival (CSS) were investigated using multivariate analysis. T stage, pre-treatment PSA, grade, radiation dose and HT were found to be independent predictors of PSA failure. T stage, grade and HT were also independent predictors of both OS and CSS, while radiation dose was a significant predictor for OS and indicated a trend (p = 0.07) for CSS. A dose of 70 Gy combined with hormonal treatment improves PSA failure free survival and survival in localised prostate cancer compared with doses of 64-66 Gy.     

Radiation therapy of esophageal cancer: role of high dose rate brachytherapy.

Fifty untreated cases of squamous cell carcinoma arising from the middle one-third of the esophagus, with no apparent extraesophageal spread on a computed tomography (CT) scan and with a Karnofsky performance status of over 70, were treated by external beam irradiation to a dose of 3500 cGy/15 fractions/3 weeks. Twenty-five patients (Group A) received treatment with further external beam irradiation to a dose of 2000 cGy/10 fractions/2 weeks. Another group of 25 patients (Group B) received treatment with high dose rate intracavitary irradiation to a dose of 1200 cGy delivered in two sessions of 600 cGy each a week apart. All patients were assessed symptomatically, endoscopically, and radiologically every 3 months. There was marked difference at the end of 1 year in relief of dysphagia (37.5% in Group A vs. 70.6% in Group B), local control (25% in group A vs. 70.6% in group B) although the results were statistically insignificant (p greater than 0.05) and actuarial survival (44% in group A vs. 78% in group B) which was, however, significant statistically (z = 2.83). The cumulative radiation effect (CRE) by external beam irradiation was 1729 reu and by external beam and intracavitary irradiation 1741 reu, but the biological dose effect was better with external beam and intracavitary irradiation. Eight percent of patients treated by external beam and intracavitary irradiation had strictures in contrast to 4% treated by external beam irradiation alone. Moderate doses of external beam and intracavitary irradiation can give a better local response than external beam irradiation alone for the same biological dose in the treatment of esophageal carcinoma.     

Radiation therapy

RT is an indispensable part of current treatment approaches of locally advanced and metastatic NSCLC. It can be used alone or in combination with surgery or CHT. Because RT can potentially cure some patients, prolong the life of others, and reduce symptoms in the majority of them, it is a unique treatment modality in this disease. Radiation oncologists have learned how to deal with RT-induced toxicities and how to improve quality of life of lung cancer patients. Although recent technologic advances made sophisticated RT somewhat more expensive than before (demanding more manpower and being more time-consuming), it is still an inexpensive treatment modality, which is important in the era of focusing on cost-effectiveness. Although newer RT technologies are used to enable effective dose-escalation-a clear must for the community of radiation oncologists--optimization of RT must also include clear identification of various pretreatment, patient, and tumor-related characteristics that may influence treatment outcome. Regardless of the current therapeutic/technologic potential, we still lack some basic knowledge to better understand the process of, for example, combining RT and CHT. There is recognized need for better translational research that ultimately should be seen as a "two-way road," from laboratory to clinic and vice versa, preferably in a continuous way. The National Cancer Institute in the United States recently organized a workshop on translational research in radiation oncology, which has identified RT-CHT interactions as one of its major areas of research. Research topics include development of the methods of imaging the results of RT/ CHT interactions (confirmed by biopsy), development of new radiation modifiers, and identification of factors other than genetic ones that may influence the response of tumors to RT/CHT interactions. Tumor microenvironment was also clearly addressed as one of the targets for research, indicating as special tasks the development of new, microenvironmentally activated cytotoxic or cytostatic drugs, development and validation of more user-friendly methods for determining tumor oxygenation, and answering whether hypoxia predicts for radioresistance to CHT in treatment and whether it causes increased tumor aggression and metastasis. The future may, therefore, be quite simple: technology meets biology.     

Radiation therapy with unflattened photon beams: Dosimetric accuracy of advanced dose calculation algorithms

Purpose

To compare the dosimetric accuracy of advanced dose calculation algorithms for flattened (FF) and unflattened (FFF) photon beams.

Material and methods

We compared the enhanced collapsed cone (eCC) algorithm implemented in OncentraMasterplan and the XVMC (MC) code in Monaco. Test plans were created for 10 MV FF and FFF beams. Single beam tests were delivered to radiochromic films positioned within a solid water phantom and evaluated with 1D γ-index analysis. Conformal plans were verified with ion chambers in an anthropomorphic thorax phantom. IMRT plans were applied to the Delta4 system and evaluated with γ-criteria of 3% and 3 mm.

Results

1D γ-index evaluation revealed significantly lower (p < 0.05) average γ_mean-values of 0.46 ± 0.22 for MC calculated FFF profiles compared to average values of 0.53 ± 0.27 detected for FF beams. Respective values for eCC were 0.42 ± 0.27/0.38 ± 0.26 (FF/FFF). When considering off-axis profiles separately, we found significantly reduced average γ_mean-values for FFF and both algorithms (MC: 0.55 ± 24 vs. 0.45 ± 0.21, eCC: 0.41 ± 0.24 vs. 0.35 ± 0.22). No significant differences were detected on-axis. Absolute dosimetry in the anthropomorphic phantom revealed superior results for MC based dose calculation, with mean deviations of 0.8 ± 0.8/0.0 ± 1.0% compared to −0.1 ± 1.7/−0.5 ± 0.1.7% (FF/FFF) for the eCC algorithm. IMRT plans showed similar results for both linac modes.

Conclusions

The dose calculation accuracy for unflattened beams was found to be at least as high as for flattened beams. The slightly improved dose calculation accuracy observed for off-axis profiles for single FFF beams did not directly translate into better verification results for composite IMRT plans.     

Radiation dose escalation using intensity modulated radiation therapy for gross unresected node-positive endometrial cancer

PurposeTo determine rates of nodal control and survival in patients with endometrial cancer treated with intensity modulated radiation therapy (IMRT) with dose escalation to unresected nodal disease.Methods and MaterialsBetween November 2005 and April 2011, 22 endometrial-cancer patients received IMRT with dose escalation to gross nodal disease with curative intent. Twelve were treated for recurrent disease (RD) and 10 in the primary setting, of whom 5 had a hysterectomy. The boost area included pelvic nodes in 9 patients (41%), paraaortic nodes (PAN) in 6 (27%) and both pelvic and PAN in 7 (32%). The median gross nodal dose was 63 Gy (range, 55-65). Rates of local control, disease-free survival (DFS) and overall survival (OS) were determined using the Kaplan-Meier method.ResultsMedian follow-up time was 37.6 months (range, 10-88). Median nodal size was 2.25 cm (range, 1-6.9). The median time to first relapse after IMRT was 12 months (range, 6-49). Relapses occurred in 5/12 RD (42%), 1/5 hysterectomy (20%), and 5/5 inoperable cases. Nodal relapses occurred in-field in 3/12 RD and 1/5 hysterectomy patients. At 3 years, nodal control was 86%, DFS was 58% and OS was 68%. Three patients experienced grade 3 late hematologic toxicity (anemia). No late grade ≥ 3 gastrointestinal or genitourinary toxicity occurred.ConclusionsIn endometrial cancer, the use of IMRT for dose escalation to gross nodal disease is feasible with acceptable rates of toxicity. Patients with nodal recurrence or unresectable nodal disease after a hysterectomy may benefit from radiation dose escalation.     

Radiation therapy in early glottic carcinoma: significance of prognostic factors and dose fractionation

A retrospective analysis of 208 cases with early glottic cancers treated by radiation therapy is presented. Early T1 (156 cases) and T2 (52 cases) lesions accounted for only 43 per cent of all glottic tumours that presented at the Tata Memorial Hospital between 1975-80. A markedly predominant male to female ratio of 22:1 was noted with 66 percent presenting in the fifth and sixth decades of life. Radical Radiation therapy was delivered with two different regimens according to the then prevalent physician preference. Regimen 1 delivered 50 Gy/15 frs. in three weeks and regimen 2 with 60 Gy/24 frs./5 weeks. The actual total survival and disease free survival was 92 per cent and 85 percent for T1 lesions and 82 percent and 67 percent for T2 tumours respectively. Minimal tumour volume involving a unilateral mobile vocal cord had the best prognosis. With extension to more lengths of cord and/or involvement of the anterior commissure or with tethering or fixation of the cord the prognosis was adversely influenced. In T1 lesions, the shorter course with the higher fractionation dosage levels showed improved local controls. However, the results were not statistically significant. This was not so in the T2 lesions probably due to small number of cases. Treatment failure was recorded in 19 per cent cases of which 90 per cent was seen in the first two years after treatment. Persisting laryngeal oedema confirmed a high index of suspicion towards recurrent disease. A radiotherapeutic technique using proper patient positioning and accurate beam direction with total dosage level above 1850 rets and TDF between 101-106 values is the recommended optimal treatment. In conclusion, an understanding of the prognostic features and an appropriate dose fractionation schedule allows optimization to effectively control early glottic tumours and retain function in the majority of patients.     

Whole-body dose from tomotherapy delivery

Purpose: To measure whole-body dose in tomotherapy of the head and neck region resulting from internal patient scatter and linear accelerator leakage.Methods and Materials: Treatments are performed using a commercial computer-controlled intensity modulated radiation therapy planning and delivery system (Peacock, NOMOS Corp.) and a 6-MV linear accelerator (Clinac 6/100, Varian Corp.). The patient dose outside the treatment field is measured in a water-equivalent phantom using thermoluminescent dosimetry. The whole-body dose components from internal scatter and leakage are separately determined. The use of fixed-portal leakage and scattered radiation measurements to estimate the whole-body dose from tomotherapy is evaluated.Results: The internally scattered dose is significant near the target, but becomes negligible relative to the leakage dose beyond 15 cm from the target. Dose at 10 cm from the target volume, due to internal scatter and leakage, is approximately 2.5% of the total target dose, reducing to 0.5% at 30 cm. The measured dose is relatively uniform throughout the phantom.Conclusion: The whole-body dose equivalent from a tomotherapy treatment is greater than that from conventional radiation therapy. Further studies are required to assess the trade-off between improved dose distribution conformality and a possible slight increase in radiation-induced fatal malignancies. The accuracy of using fixed-portal leakage and scattered dose measurements to estimate the whole-body dose from tomotherapy treatments is adequate, if the appropriate fixed-portal field size equivalent is used.     

Radiation dose response of normal brain

Dose response relationships were determined after hemibrain x-irradiation of normal beagle dogs. Radiation doses of 11.5, 13.5, 14.3, and 17 Gy were delivered in a single dose and results were compared to previous studies using doses of 15 and 30 Gy. Brain injury was quantified using computed tomography (CT), with serial studies obtained monthly up to 1 year following irradiation. Quantitative endpoints included low density volume and contrast enhancement. Doses above 14.3 Gy resulted in high lethality 5-8 months following irradiation, and an LD50 of 14.9 Gy was calculated. At these lethal doses, low density volume representing edema, demyelination, and necrosis had a similar response with an ED50 of 14.6 Gy. Radiation-induced decreases in white matter density appeared 5-6 months after sublethal doses (less than or equal to 14.3 Gy) and the volume of tissue characterized by this low density increased with time and dose. This sublethal low density change had an ED50 of 12.8 Gy, and may reflect a loss or generalized atrophy of glial cells and/or myelin. These results show that: (a) the dose response curves obtained after hemibrain x-irradiation are extremely steep; and (b) at least two processes may be involved in the development of late radiation damage, one that is rapid upon onset (a "delayed acute" reaction) and the other which is a slower and more degenerative process.     

Radiation dose and second breast cancer

Amongst 14,000 women with breast cancer treated between 1946 and 1982, 194 developed a second primary tumour in the contralateral breast more than one year after diagnosis of the first primary. The radiation dose to the contralateral breast was calculated for each member of this group and also for members of a control group matched for age, year of diagnosis and survival time. Comparison of the groups provides no evidence for radiation induced carcinogenesis on the contralateral breast in these patients.     

The optimization of dose delivery for intraoperative high-dose-rate radiation therapy using curved HAM applicators.

BACKGROUND AND PURPOSE: To determine the effect of the curvature of Harrison-Anderson-Mick applicators on the dose distribution in high-dose-rate intraoperative radiation therapy (HDR-IORT). MATERIAL AND METHODS: Treatment planning was performed with flat applicators using (192)Ir as the radioactive source, and dwell times were optimized using dose-point optimization techniques. These optimized dwell times were then used for the curved applicators, and the dose distributions that would actually be delivered to patients were determined. RESULTS: The dose directly below the central catheter was strongly dependent on the curvature of the applicator. Steep parabolic curves caused underdoses of as much as 19% at a point 1cm from the convex side of the applicator. The rate of dose reduction with increasing distance from the applicator surface was also a function of the curvature of the applicator. CONCLUSIONS: The curvature of the applicator profoundly affects dosimetry and can be exploited to optimize coverage of the target during HDR-IORT procedures. To ensure accurate dose delivery, these dose perturbations must be accounted for in the planning process. We recommend maintaining a dosimetry atlas of various applicator sizes and curvatures in addition to one for flat applicators.     

Radiation dose selection in Hodgkin's disease patients with large mediastinal adenopathy treated with combined modality therapy

PURPOSE: To determine the effective dose of consolidation radiation in Hodgkin's disease (HD) patients with large mediastinal adenopathy (LMA) treated with combined modality therapy (CMT). METHODS AND MATERIALS: Eighty-three HD patients with LMA receiving CMT between 1983 and 1997 at Duke University and Yale University were identified. Patients underwent complete clinical staging. The staging breakdown was: IA, 4 patients; IB, 1 patient; IIA, 25 patients; IIB, 33 patients; IIIA, 3 patients; IIIB-6 patients; IVA, 2 patients; and IVB, 9 patients. All patients received induction chemotherapy (CT) as follows: MOPP/ABV(D), 31 patients; BCVPP, 15 patients; ABVD, 24 patients; MOPP, 3 patients; and other regimens, 10 patients. Following 6 cycles of CT, patients were restaged and classified as having either complete response (CR) or induction failure (IF). Post-CT gallium scans were obtained in 52 patients. Patients with residual radiographic abnormalities were classified as having CR if they were gallium-negative and clinically well otherwise. Following induction CT, 78 patients had a CR. There were 5 IFs. Consolidation irradiation was administered to all sites of initial involvement in patients who had achieved CR. RT dose varied. Patients were grouped into the following dose ranges: < or = 20 Gy, 12 patients; 20-25 Gy, 24 patients; 25-30 Gy, 30 patients; > or = 30 Gy, 12 patients. RESULTS: Overall survival and failure-free survival were both 76% at 10 years. Of the 78 CR patients, 15 failed. Patterns of failure were in-field alone, 8 patients; out of field alone, 2 patients; and combined, 5 patients. Failure patterns by RT dose were: < or = 20 Gy, 0/12; 20-25 Gy, 7/24; 25-30 Gy, 5/30; > or = 30 Gy, 3/11. There was no apparent correlation between RT dose and subsequent failure. Post chemotherapy gallium scans were helpful in predicting for failure. Of 48 patients in whom the gallium was negative after chemotherapy, there were 6 failures, compared with 9 failures among 30 patients in whom gallium was not done after chemotherapy (p = 0.066). Additionally, patients receiving adriamycin-based chemotherapy regimens had improved outcomes compared to those not receiving adriamycin (p = 0.03.) CONCLUSIONS: These retrospective data suggest that low-dose radiotherapy following CR achieved with induction chemotherapy (particularly when documented with gallium scanning) may be as effective as higher doses for bulky HD at presentation. Phase III trials are necessary for confirmation of this hypothesis.     

50例鼻咽癌调强放疗中内耳受量评价

目的：分析鼻咽癌调强放疗对双侧内耳受量的影响。方法：选择2015年5月至12月就诊于成都军区总医院50例经病理确诊为鼻咽癌的患者,所有患者均接受30次调强放疗。再由一名主治医师在原始的CT图像上勾画出双侧的耳蜗、前庭及内耳道,并在计划的优化过程中对上述结构进行条件一致的剂量限定,最后通过DVH图对上述结构进行剂量分析,包括最大剂量点（Dmax ）、最小剂量点（Dmin ）及平均剂量（Dmean ）。结果：左侧耳蜗的最大剂量点、最小剂量点及平均剂量的均值分别为5366．3cGy、3981．2cGy、4550．1cGy;左侧前庭分别为4323．2cGy、3310．8cGy、3821．1cGy;左侧内耳道分别为5290．8cGy、3828．7cGy、4453．6cGy;右侧耳蜗的最大剂量点、最小剂量点及平均剂量的均值分别为5344．5cGy、3954．2cGy、4550．1cGy;右侧前庭分别为4368．3cGy、3262．9cGy、3796．0cGy;右侧内耳道分别为5165．0cGy、3765．2cGy、4375．2cGy。结论：在鼻咽癌的调强放疗计划设计过程中对内耳结构进行剂量限定,能在不减少靶区受量的同时有效的降低内耳结构的受照射剂量。     

Radiation dose escalation for localized prostate cancer

BACKGROUND:

In the current study, the effects of dose escalation for localized prostate cancer treatment with intensity‐modulated radiotherapy (IMRT) or permanent transperineal brachytherapy (BRT) in comparison with conventional dose 3‐dimensional conformal radiotherapy (3D‐CRT) were evaluated.

METHODS:

This study included 853 patients; 270 received conventional dose 3D‐CRT, 314 received high‐dose IMRT, 225 received BRT, and 44 received external beam radiotherapy (EBRT) + BRT boost. The median radiation doses were 68.4 grays (Gy) for 3D‐CRT and 75.6 Gy for IMRT. BRT patients received a prescribed dose of 144 Gy with iodine‐125 (I‐125) or 120 Gy with palladium‐103 (Pd‐103), respectively. Patients treated with EBRT + BRT received 45 Gy of EBRT plus a boost of 110 Gy with I‐125 or 90 Gy with Pd‐103. Risk group categories were low risk (T1‐T2 disease, prostate‐specific antigen level ≤10 ng/mL, and a Gleason score ≤6), intermediate risk (increase in value of 1 of the factors), and high risk (increase in value of ≥2 factors).

RESULTS:

With a median follow‐up of 58 months, the 5‐year biochemical control (bNED) rates were 74% for 3D‐CRT, 87% for IMRT, 94% for BRT, and 94% for EBRT + BRT (P <.0001). For the intermediate‐risk group, high‐dose IMRT, BRT, or EBRT + BRT achieved significantly better bNED rates than 3D‐CRT (P <.0001), whereas no improvement was noted for the low‐risk group (P = .22). There was no increase in gastrointestinal (GI) toxicity from high‐dose IMRT compared with conventional dose 3D‐CRT, although there was more grade 2 genitourinary (GU) toxicity (toxicities were graded at the time of each follow‐up visit using a modified Radiation Therapy Oncology Group [RTOG] scale). BRT caused more GU but less GI toxicity, whereas EBRT + BRT caused more late GU and GI toxicity than IMRT or 3D‐CRT.

CONCLUSIONS:

The data from the current study indicate that radiation dose escalation improved the bNED rate for the intermediate‐risk group. IMRT caused less acute and late GU toxicity than BRT or EBRT + BRT. Cancer 2009. © 2009 American Cancer Society.     

金属植入物对放射治疗剂量影响的研究

目的:测量金属内固定支架对放射治疗剂量的影响,对采用金属内固定的肿瘤患者放射治疗提供剂量修正的临床数据。方法:按照测量条件,将带有金属内固定支架的体模在螺旋CT下进行扫描,层厚为5mm,图像通过LANTIS网络传输系统传入放射治疗计划系统(treatment planning system,TPS)中进行模拟计算。按照相同条件,分别用6MV和15 MVX线照射,用热释光剂量仪和FAMER型电离室对钛镍合金支架界面以及界面上下一定深度分别测量,并与放射治疗计划系统计算结果比较。结果:实际测量与TPS计算存在一定误差,实测值明显大于TPS计算值,支架前表面的误差最大可达3.9%(6MV)和6.6%(15MV),支架后表面的误差最大为2.8%(6MV)和6.3%(15MV),距表面距离越远,误差越小。结论:镍钛合金支架患者放射治疗时,实际测量剂量比TPS计算剂量要大,有可能增加放射性损伤。TPS计算过程中,虽然对金属物进行了密度修正,但仍存在一定误差,有必要在制订放疗计划时对照射剂量进行修正。     

对比增强能谱乳腺X线摄影的辐射剂量分析

背景与目的：对比增强能谱乳腺X线摄影(contrast-enhanced spectral mammography,CESM)是近几年推出的一项新技术,它是基于常规乳腺X线摄影的一项检查技术。该研究通过对低能图与CESM两种影像检查方法的平均腺体剂量进行比较,对CESM检查方法的辐射剂量进行分析。方法：收集143例临床可触及乳腺肿块的患者,根据腺体类型进行分类,其中脂肪型(a)7例,散在纤维腺体型(b)31例,不均匀致密型(c)76例,极度致密型(d)29例;根据病变部位进行分类,其中右侧乳腺肿块70例,左侧乳腺肿块64例,双侧乳腺肿块9例;年龄分布小于40岁有27例,41~50岁有51例,51~60岁有50例,61~70岁有15例。对患者进行划分,比较各腺体类型、健侧或患侧乳腺及不同年龄段的低能图与CESM两种影像检查方法的平均腺体剂量。结果：共计143例患者,CESM检查的AGD较低能图的AGD高26.22%,差异存在统计学意义(P<0.05)。不同乳腺腺体类型的CESM和低能图曝光剂量组内差异均有统计学意义(P<0.05);对CESM和低能图的曝光剂量组间比较时,a、b、c和d型腺体类型的AGD分别增加了26.05%、25.92%、26.82%和24.93%,可见c型腺体的AGD增幅最大,d型腺体的AGD增幅最少(P<0.05)。CESM检查时患侧乳腺的AGD较健侧乳腺的AGD高4.15%,差异有统计学意义(P<0.05)。各年龄段中CESM和低能图的AGD值组内、组间差异均有统计学意义(P<0.05),其中两个患者数较多的年龄段41~50岁、51~60岁的组间两两比较差异有统计学意义(P<0.05)。结论：CESM影像检查方法的辐射剂量略高于低能图,不同乳腺腺体类型、病变部位及年龄段之间均有差异,但仍是一种安全、可靠的检查技术,临床可根据实际需要开展应用。