AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent fou...AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIBbased neoadjuvant chemoradiation protocol.During the concurrent chemoradiation therapy,radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume,with a regimen at the discretion of the treating medical oncologist.This was followed by surgical tumor resection.We analyzed pathological completion response(p CR)rates its relationship with overall survival and event-freesurvival.RESULTS:Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis.Among the IMRT-SIB-treated patients,the toxicity appeared mild,the most common side effects were grade 1-3 esophagitis(46%)and pneumonitis(11.7%).There were no cardiac events.The Ro resection rate was 94%(n=16),the p CR rate was 47%(n=8),and the postoperative morbidity was zero.There was one mediastinal failure found,one patient had local failure at the anastomosis site,and the majority of failures were distant in the lung or bone.The 3-year diseasefree survival and overall survival rates were 41%(n=7)and 53%(n=9),respectively.CONCLUSION:The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications.展开更多
AIM:To study the leakage-penumbra(LP)effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS:Leakage-penumbra dose profiles from 10 randomly selected prostat...AIM:To study the leakage-penumbra(LP)effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS:Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied.The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC).For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated.For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV).The overshoot effect(OSE)and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V)radiographic films.Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16).The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations.RESULTS:A non-uniformly distributed leaf LP dose ranging from 3%to 5%of the beam dose was measured in clinical IMRT beams.An overdose at the gap between neighboring segments,represented as dose peaks of up to 10%of the total BP,was measured.The LP effect increased the dose to the PTV and surrounding critical tissues.In addition,the effectdepends on the number of beams and segments for each beam.Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans.The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection.As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams.CONCLUSION:We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected.展开更多
Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty pati...Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine+cispatin (NP) was used in chemotherapy. Results: (1) The overall response (CR+PR) rate was 75% in concurrent group and 45% in sequential group (P<0.05); (2) The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively (P<0.05); (3) One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; (4) The toxic effects can be tolerable by all of patients. Conclusion: The concurrent chemo-radiotherapy has better overall re- sponse, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.展开更多
Objective:Serum prostate specific antigen(PSA)is commonly used to evaluate treatment response after definitive radiation therapy(RT).However,PSA levels can temporarily rise without a clear reason,termed“PSA bounce”,...Objective:Serum prostate specific antigen(PSA)is commonly used to evaluate treatment response after definitive radiation therapy(RT).However,PSA levels can temporarily rise without a clear reason,termed“PSA bounce”,and often engender great anxiety for both patients and physicians.The present study aimed to determine the prevalence and factors that predict“PSA bounce”after intensity-modulated radiation therapy(IMRT),and the relevance to biochemical failure and cancer recurrence in an Asian population.Methods:We retrospectively reviewed 206 patients who received IMRT for prostate cancer from 2004 to 2012 in the National Cancer Centre Singapore.These patients were followed up with regular PSA monitoring.We defined“PSA bounce”as a rise of 0.1 ng/mL,followed by two consecutive falls.Patients with biochemical failure(PSA nadir t 2 ng/mL)were further evaluated for cancer recurrence.Results:Sixty-one patients(29.6%)experienced“PSA bounce”,at a median time of 16 months and lasted for 12 months.Age remained the most consistent predictor of the incidence,duration and extent of“PSA bounce”.Other contributory factors included baseline PSA,Gleason score and PSA nadir.Hormonal therapy and prostate volume did not affect this phenomenon.Sixteen patients(7.8%)developed biochemical recurrence,at median time of 32 months,of which 11 were confirmed to have metastatic disease.The median follow-up time was 71 months.展开更多
Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong r...Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined. In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone. The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study. The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.展开更多
AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT an...AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT).Dose were 63.8 Gy(HT)and 63.2 Gy(VMAT)in the tumour bed,52.2 Gy in the breast,50.4 Gy in supraclavicular nodes(SCN)and internal mammary chain(IMC)with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions.Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort,the coverage of clinical target volumes was as follows:Tumour bed:99.4%±2.4%;breast:98.4%±4.3%;SCN:99.5%±1.2%;IMC:96.5%±13.9%.For the VMAT cohort,the coverage was as follows:Tumour bed:99.7%±0.5%,breast:99.3%±0.7%;SCN:99.6%±1.4%;IMC:99.3%±3%.For ipsilateral lung,Dmean and V20 were 13.6±1.2 Gy,21.1%±5%(HT)and 13.6±1.4 Gy,20.1%±3.2%(VMAT).Dmean and V30 of the heart were 7.4±1.4 Gy,1%±1%(HT)and 10.3±4.2 Gy,2.5%±3.9%(VMAT).For controlateral breast Dmean was 3.6±0.2 Gy(HT)and 4.6±0.9 Gy(VMAT).Acute skin toxicity grade 3 was 5%in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance.A longer follow-up is needed to assess the impact of low doses to healthy tissues.展开更多
The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52...The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52-year-old male with known metastatic HCC,who presented with severe proptosis and diplopia.An orbital mass was identified on magnetic resonance imaging(MRI)and confirmed to have hypermetabolic activity on positron emission tomography/computed tomography.He received a palliative course of external beam radiation therapy to the right orbit.Intensity modulated radiation therapy (IMRT)was used to allow sparing of critical norma tissues in close proximity to the tumor.One month after completion of IMRT to 58 Gray in 30 fractions delivered over 6 wk,the patient had a complete clinical,radiologic(MRI)and symptomatic response The patient continues to have local control in the orbi 1.7 years after therapy completion.All critical norma structures were kept below the tolerance dose using IMRT,and no toxicities were observed.展开更多
To the Editor:Graft-versus-host disease(GVHD)is a rare but fatal complication after solid organ transplantation(SOT),with an incidence of 0.2–2.0%.Recent retrospective studies have shown a mortality rate of approxima...To the Editor:Graft-versus-host disease(GVHD)is a rare but fatal complication after solid organ transplantation(SOT),with an incidence of 0.2–2.0%.Recent retrospective studies have shown a mortality rate of approximately 85–98%among patients with SOT-GVHD.[1]Various drugs and methods have been shown to improve or alleviate clinical symptoms,but no effective treatments for GVHD currently exist.Recent clinical experience with SOTGVHD treatment is mixed and limited,including systemic or partial corticosteroid support,the use of Janus kinase(JAK)inhibitors,allogeneic hematopoietic cell transplantation(alloHCT),and donor-targeted serotherapy.Since the number of lymphocytes transplanted with the organ may be a risk factor for GVHD,reducing the number of donor lymphocytes seems beneficial.Intensity-modulated radiation therapy(IMRT)is a type of radiotherapy that uses optimized,non-uniform radiation beam intensities on the patient.[2]Local allograft irradiation has also been used to treat severe resistant rejection after liver transplantation(LT)in previous studies.[3]Based on this,we hypothesized that whole-liver IMRT at a low dosage could be used as a rescue therapy to control acute GVHD after LT by reducing the number of donor-derived immune cells.展开更多
Objective:The incidence of primary tracheal neoplasm is extremely rare.Squamous cell carcinoma(SCC)is the most prevalent histological type of tracheal malignancy.Postoperative adjuvant radiotherapy can be considered a...Objective:The incidence of primary tracheal neoplasm is extremely rare.Squamous cell carcinoma(SCC)is the most prevalent histological type of tracheal malignancy.Postoperative adjuvant radiotherapy can be considered as a curative management option.However,there are limited data available on the use of radiotherapy or concurrent chemoradiotherapy for tracheal cancer,particularly intensity-modulated radiotherapy.Patient and methods:Herein,we present a case report of a young adult male diagnosed with primary SCC of the trachea who underwent postoperative concurrent chemoradiotherapy utilizing intensity-modulated radiation therapy(IMRT).The treatment included 50.4 Gy radiation in 28fractions and two cycles of chemotherapy.Results:The patient experienced gradeⅠdermatitis and gradeⅡgranulocytosis.Follow-up showed no evidence of recurrence or significant adverse effects.The patient achieved 5-year long-term survival with good quality of life.Conclusion:Postoperative concurrent chemoradiotherapy using IMRT is effective for primary tracheal carcinoma,offering long-term survival and quality of life benefits.展开更多
Chondrosarcomas are malignant bone tumors which develop as a cartilaginous differentiation of primary mesenchymal cells and the second most frequently seen malignant tumor of the bone after osteosarcoma. These maligna...Chondrosarcomas are malignant bone tumors which develop as a cartilaginous differentiation of primary mesenchymal cells and the second most frequently seen malignant tumor of the bone after osteosarcoma. These malignancies are slowly growing non-epithelial tumors with unknown etiology and most frequently seen during the 4 decades of life. They are frequently localized on pelvis, ribs and long bones. Nasal septum CSs are very rarely seen malignancies. They originate from septal mucosa or cartilage and it is difficult to make a diagnosis unless they reach a certain size. A few cases of CSs with nasal septum have been reported in the literature. In cases of CSs, surgery is the gold standard treatment modality;however in surgically unresectable cases or close to margins, radiotherapy plays a significant role in primary and adjuvant treatment. Based on the position of the tumor in head and neck and extremely closeness of the tumor to vital organs as optic nerve, chiasm and brain, image guided-intensity modulated radiation therapy (IG-IMRT) becomes very effective and reliable modalities and may be a favorable treatment alternative.展开更多
BACKGROUND Neoadjuvant chemoradiotherapy(NACRT)has not been accepted as a general therapy for gastric cancer because of its localized effect and toxicity for radiosensitive organs.However,if radiation therapy could co...BACKGROUND Neoadjuvant chemoradiotherapy(NACRT)has not been accepted as a general therapy for gastric cancer because of its localized effect and toxicity for radiosensitive organs.However,if radiation therapy could compensate for the limited or inadequate treatment choices available for elderly patients and/or those at high risk,the available therapeutic options for advanced gastric cancer might increase.From this perspective,we present our experiences of five patients with advanced gastric cancer in whom we used NACRT therapy with interesting results.CASE SUMMARY We admitted five patients with clinical Stage III gastric cancer and bulky lymph node metastasis or adjacent organ invasion at the time of diagnosis.A total of 50 Gy of preoperative intensity modulated radiation therapy was delivered to the patients in doses of 2.0 Gy/d,together with a regimen of concomitant chemotherapy comprising two courses of oral tegafur/gimeracil/oteracil(S-1;65 mg/m2 per day)for three consecutive weeks followed by two weeks of rest,starting at the same time as radiotherapy.All patients underwent no residual tumor resection and a pathological complete response of the primary tumors was achieved in two patients.The incidence of hematological toxicity was low,although the digestive toxicities of anorexia and diarrhea developed in three of the five patients,necessitating termination of radiation therapy at 30 Gy and S-1 at three weeks.However,even 30 Gy of irradiation and half the dose of S-1 resulted in sufficient downstaging,indicating that even a reduced amount of NACRT could confer considerable effects.CONCLUSION Slightly reduced NACRT might be useful and safe for patients with locally advanced gastric cancer.展开更多
In order to explore a dose distribution verification procedure of intensity modulated radiation therapy （IMRT） for nasopharyngeal carcinoma （NPC） and establish its evaluation criteria, we performed 35 two-dimensio...In order to explore a dose distribution verification procedure of intensity modulated radiation therapy （IMRT） for nasopharyngeal carcinoma （NPC） and establish its evaluation criteria, we performed 35 two-dimensional （2D） patient-specific IMRT verifications over the year i006. The percent of pixels passing 7 and the normalized agreement test （NAT） index were mainly used to represent the agreement between the measured and computed dose distributions with three criteria （2%/2 mm, 3%/3 mm and 5%/3 mm） as recommended in the literature. The results were that all cases passed through verifications with three criteria except that the NAT index of one case was beyond the limitation, and the three tolerance levels of 2%/2mm, 3%/3 mm and 5%/3 mm produced similar clinical verification results but led to different percent of pixels passing Y and NAT index. Our data showed that the percent of pixels passing y and the NAT index were complementary to evaluate future IMRT verifications as two significant metrics. Due to the influence of the noise and the trait of the software, we considered an IMRT plan as acceptable in case of the percent ofpixels passing y 〉95% and the NAT index 〈5 with the 5%/3 mm criteria for IMRT patient-specific quality assurance （QA）.展开更多
We developed the first non-commercial treatment planning system for volumetric modulated arc therapy(VMAT) in the United States. Because VMAT involves multi-parameter modulations, it is imperative to develop a compreh...We developed the first non-commercial treatment planning system for volumetric modulated arc therapy(VMAT) in the United States. Because VMAT involves multi-parameter modulations, it is imperative to develop a comprehensive, rigorous and yet, practical procedure for routine patient-specific quality assurance(QA). In this paper, we presented our own approach as being currently implemented in our institution.Our patient-specific QA procedure involves multi-levels: pre-treatment QA,on-treatment QA, and posttreatment QA. The pre-treatment QA focuses on dosimetry verification, which is done with the commercial Map CHECK in Map PHAN mounted on an isocentric mounting fixture(IMF). This method is also referred to the fixed-gantry technique,i.e., the beams always remain perpendicular to the detector plane. The on-treatment QA involves in vivo optically stimulated luminescent dosimetry(OSLD).Prior to the treatment, two nano Dot TM OSLD dosimeters are placed on the patient abdomen under 1 cm bolus at the isocenter location. The irradiated dosimeters are then read by a nano Dot TM reader and the average reading of the two is calculated. The post-treatment QA involves the analysis of the Dyna Log and DLog files. The Dyna Log is a treatment log file that contains the planned and actual leaf positions at a given gantry angle. The DLog is a treatment log file that contains the planned segmented treatment table(STT) and the corresponding segment boundary samples, i.e., the actual delivered MU and gantry angle increment at each control point.展开更多
1.Introduction Nasopharyngeal carcinoma(NPC)has an imbalanced geographical and ethnic distribution,with notably high incidence rates in Southeastern Asia and China.China accounted for 42.4%of the newly diagnosed cases...1.Introduction Nasopharyngeal carcinoma(NPC)has an imbalanced geographical and ethnic distribution,with notably high incidence rates in Southeastern Asia and China.China accounted for 42.4%of the newly diagnosed cases worldwide in 2022.1NPC is sensitive to irradiation,and radiotherapy is the mainstay curative treatment modality.2The widespread use of intensity-modulated radiation therapy(IMRT)and image-guided radiotherapy(IGRT)has achieved great advances in survival outcomes and toxicity profiles among NPC patients.1In radiotherapy of NPC,the tumor’s proximity to critical structures demands accuracy in tumor delineation in order to avoid radiation-induced toxicities.However,tumor target delineation for radiotherapy of NPC is labor-intensive and radiation oncologists’proficiency varied considerably.3In recent years,the advent of big data analytics and artificial intelligence(AI)has opened up new avenues for improving the precision and efficacy of radiotherapy and individualized treatment in NPC management.3-6In this article,we explored how big data,AI-assisted delineation,radiotherapy planning,and adaptive radiotherapy(ART)are transforming clinical decision-making in NPC treatment.We also provided an outlook on the historical development of AI and big data,their current dominance in oncological radiotherapy,and their projected impact on future clinical practice(Figure 1).展开更多
With the continuous development of science and technolog ies in China,radiotherapy technology in medical field has been very significant ly developing,and intensity modulated radiation therapy(IMRT)technology has been...With the continuous development of science and technolog ies in China,radiotherapy technology in medical field has been very significant ly developing,and intensity modulated radiation therapy(IMRT)technology has been the most widely used.This paper first introduces the components and types of two-dimensional matrix detector,two-dimensional ionization chamber matrix detector and two-dimensional semiconductor matrix detector,then analyzes the dosimetric characteristics of the two-dimensional matrix detector.In the end,the various applications of the two-dimensional matrix detector are analyzed and discussed in detail.The paper aims to promote the two-dimensional matrix detector’s development in the field of radiotherapy in China.展开更多
Radiotherapy plays a critical role in the treatment of oral cavity squamous cell carcinoma as monotherapy in early stage cancer or combined with surgery and/or chemotherapy in advances ones.Recent developments in the ...Radiotherapy plays a critical role in the treatment of oral cavity squamous cell carcinoma as monotherapy in early stage cancer or combined with surgery and/or chemotherapy in advances ones.Recent developments in the imaging of cancer and radiation technology have allowed developing more precise delivery of treatment with recent data demonstrating improvement in survival and lessening of adverse toxics effects of radiation.This review will focus in the recent advances and current state-of-the-art in radiation oncology both external beam radiotherapy and brachytherapy.As complexity of cancer treatments increases a close coordination between head-neck surgeons and radiation oncologist is needed due to a significant proportion of patients will be treated with combined modality therapy.展开更多
Background: For image-guided radiotherapy(IGRT) of prostate cancer, the current standard is online image guidance which can effectively correct setup errors and inter-fraction rigid organ motion. However, planning mar...Background: For image-guided radiotherapy(IGRT) of prostate cancer, the current standard is online image guidance which can effectively correct setup errors and inter-fraction rigid organ motion. However, planning margins are still necessary for deformation and intra-fraction motion. Objective: This paper aims to investigate an adaptive planning technique incorporating offline dose feedback to manage interfraction motion and residuals from online corrections. Methods:Repeated CT scans from 28 patients were studied. Online IG was simulated by matching center-of-mass of prostate. A seven-beam IMRT plan with zero margins was designed for each patient. Dose distribution at each fraction was evaluated based on actual target and OARs from that fraction. Cumulative dose was calculated using deformable registration and compared to initial plan. If deviation exceeded pre-defined 2% threshold in prostate D99 an adaptive planning technique called dose compensation was invoked, in which cumulative dose was fed back to the planning system and dose deficit was made up through boost radiation in future fractions through IMRT. Results: If 2% under-dose was allowed at the end of course, then 11 patients failed. If the same criteria was assessed at the end of each week(every 5 fractions), then 14 patients failed. The average dose deficit for these 14 patients was4.4%. They improved to 2% after weekly compensation. 10(out of 14) patients passed criterion after weekly dose compensation; 3 failed marginally; 1 failed significantly(10% deficit). A more aggressive compensation frequency(every 3 fractions) could reduce the dose deficit to the acceptable level for this patient. The doses to OARs were not significantly different from online IG only without dose compensation.Conclusion: We demonstrated an offline dose compensation technique in prostate IGRT which can effectively account for residual uncertainties uncorrectable in online IG. Dose compensation allows further margin reduction and critical organs sparing.展开更多
文摘AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIBbased neoadjuvant chemoradiation protocol.During the concurrent chemoradiation therapy,radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume,with a regimen at the discretion of the treating medical oncologist.This was followed by surgical tumor resection.We analyzed pathological completion response(p CR)rates its relationship with overall survival and event-freesurvival.RESULTS:Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis.Among the IMRT-SIB-treated patients,the toxicity appeared mild,the most common side effects were grade 1-3 esophagitis(46%)and pneumonitis(11.7%).There were no cardiac events.The Ro resection rate was 94%(n=16),the p CR rate was 47%(n=8),and the postoperative morbidity was zero.There was one mediastinal failure found,one patient had local failure at the anastomosis site,and the majority of failures were distant in the lung or bone.The 3-year diseasefree survival and overall survival rates were 41%(n=7)and 53%(n=9),respectively.CONCLUSION:The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications.
文摘AIM:To study the leakage-penumbra(LP)effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS:Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied.The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC).For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated.For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV).The overshoot effect(OSE)and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V)radiographic films.Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16).The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations.RESULTS:A non-uniformly distributed leaf LP dose ranging from 3%to 5%of the beam dose was measured in clinical IMRT beams.An overdose at the gap between neighboring segments,represented as dose peaks of up to 10%of the total BP,was measured.The LP effect increased the dose to the PTV and surrounding critical tissues.In addition,the effectdepends on the number of beams and segments for each beam.Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans.The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection.As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams.CONCLUSION:We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected.
基金Supported by a grant from Health Bureau of Lianyungang City’s Fund Program (No. 05051).
文摘Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine+cispatin (NP) was used in chemotherapy. Results: (1) The overall response (CR+PR) rate was 75% in concurrent group and 45% in sequential group (P<0.05); (2) The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively (P<0.05); (3) One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; (4) The toxic effects can be tolerable by all of patients. Conclusion: The concurrent chemo-radiotherapy has better overall re- sponse, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.
文摘Objective:Serum prostate specific antigen(PSA)is commonly used to evaluate treatment response after definitive radiation therapy(RT).However,PSA levels can temporarily rise without a clear reason,termed“PSA bounce”,and often engender great anxiety for both patients and physicians.The present study aimed to determine the prevalence and factors that predict“PSA bounce”after intensity-modulated radiation therapy(IMRT),and the relevance to biochemical failure and cancer recurrence in an Asian population.Methods:We retrospectively reviewed 206 patients who received IMRT for prostate cancer from 2004 to 2012 in the National Cancer Centre Singapore.These patients were followed up with regular PSA monitoring.We defined“PSA bounce”as a rise of 0.1 ng/mL,followed by two consecutive falls.Patients with biochemical failure(PSA nadir t 2 ng/mL)were further evaluated for cancer recurrence.Results:Sixty-one patients(29.6%)experienced“PSA bounce”,at a median time of 16 months and lasted for 12 months.Age remained the most consistent predictor of the incidence,duration and extent of“PSA bounce”.Other contributory factors included baseline PSA,Gleason score and PSA nadir.Hormonal therapy and prostate volume did not affect this phenomenon.Sixteen patients(7.8%)developed biochemical recurrence,at median time of 32 months,of which 11 were confirmed to have metastatic disease.The median follow-up time was 71 months.
文摘Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined. In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone. The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study. The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.
文摘AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT).Dose were 63.8 Gy(HT)and 63.2 Gy(VMAT)in the tumour bed,52.2 Gy in the breast,50.4 Gy in supraclavicular nodes(SCN)and internal mammary chain(IMC)with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions.Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort,the coverage of clinical target volumes was as follows:Tumour bed:99.4%±2.4%;breast:98.4%±4.3%;SCN:99.5%±1.2%;IMC:96.5%±13.9%.For the VMAT cohort,the coverage was as follows:Tumour bed:99.7%±0.5%,breast:99.3%±0.7%;SCN:99.6%±1.4%;IMC:99.3%±3%.For ipsilateral lung,Dmean and V20 were 13.6±1.2 Gy,21.1%±5%(HT)and 13.6±1.4 Gy,20.1%±3.2%(VMAT).Dmean and V30 of the heart were 7.4±1.4 Gy,1%±1%(HT)and 10.3±4.2 Gy,2.5%±3.9%(VMAT).For controlateral breast Dmean was 3.6±0.2 Gy(HT)and 4.6±0.9 Gy(VMAT).Acute skin toxicity grade 3 was 5%in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance.A longer follow-up is needed to assess the impact of low doses to healthy tissues.
文摘The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52-year-old male with known metastatic HCC,who presented with severe proptosis and diplopia.An orbital mass was identified on magnetic resonance imaging(MRI)and confirmed to have hypermetabolic activity on positron emission tomography/computed tomography.He received a palliative course of external beam radiation therapy to the right orbit.Intensity modulated radiation therapy (IMRT)was used to allow sparing of critical norma tissues in close proximity to the tumor.One month after completion of IMRT to 58 Gray in 30 fractions delivered over 6 wk,the patient had a complete clinical,radiologic(MRI)and symptomatic response The patient continues to have local control in the orbi 1.7 years after therapy completion.All critical norma structures were kept below the tolerance dose using IMRT,and no toxicities were observed.
基金supported by a grant from the Key Research and Development Plan of Hubei Province(No.2022BCA015).
文摘To the Editor:Graft-versus-host disease(GVHD)is a rare but fatal complication after solid organ transplantation(SOT),with an incidence of 0.2–2.0%.Recent retrospective studies have shown a mortality rate of approximately 85–98%among patients with SOT-GVHD.[1]Various drugs and methods have been shown to improve or alleviate clinical symptoms,but no effective treatments for GVHD currently exist.Recent clinical experience with SOTGVHD treatment is mixed and limited,including systemic or partial corticosteroid support,the use of Janus kinase(JAK)inhibitors,allogeneic hematopoietic cell transplantation(alloHCT),and donor-targeted serotherapy.Since the number of lymphocytes transplanted with the organ may be a risk factor for GVHD,reducing the number of donor lymphocytes seems beneficial.Intensity-modulated radiation therapy(IMRT)is a type of radiotherapy that uses optimized,non-uniform radiation beam intensities on the patient.[2]Local allograft irradiation has also been used to treat severe resistant rejection after liver transplantation(LT)in previous studies.[3]Based on this,we hypothesized that whole-liver IMRT at a low dosage could be used as a rescue therapy to control acute GVHD after LT by reducing the number of donor-derived immune cells.
基金supported by the National Natural Science Foundation of China(82460958)the National Superior Specialty of TCM(National TCM Medical Policy Letter(2024)No.90)the Guangxi Key Discipline Construction Project of Traditional Chinese Medicine(GZXK-Z-20-20)
文摘Objective:The incidence of primary tracheal neoplasm is extremely rare.Squamous cell carcinoma(SCC)is the most prevalent histological type of tracheal malignancy.Postoperative adjuvant radiotherapy can be considered as a curative management option.However,there are limited data available on the use of radiotherapy or concurrent chemoradiotherapy for tracheal cancer,particularly intensity-modulated radiotherapy.Patient and methods:Herein,we present a case report of a young adult male diagnosed with primary SCC of the trachea who underwent postoperative concurrent chemoradiotherapy utilizing intensity-modulated radiation therapy(IMRT).The treatment included 50.4 Gy radiation in 28fractions and two cycles of chemotherapy.Results:The patient experienced gradeⅠdermatitis and gradeⅡgranulocytosis.Follow-up showed no evidence of recurrence or significant adverse effects.The patient achieved 5-year long-term survival with good quality of life.Conclusion:Postoperative concurrent chemoradiotherapy using IMRT is effective for primary tracheal carcinoma,offering long-term survival and quality of life benefits.
文摘Chondrosarcomas are malignant bone tumors which develop as a cartilaginous differentiation of primary mesenchymal cells and the second most frequently seen malignant tumor of the bone after osteosarcoma. These malignancies are slowly growing non-epithelial tumors with unknown etiology and most frequently seen during the 4 decades of life. They are frequently localized on pelvis, ribs and long bones. Nasal septum CSs are very rarely seen malignancies. They originate from septal mucosa or cartilage and it is difficult to make a diagnosis unless they reach a certain size. A few cases of CSs with nasal septum have been reported in the literature. In cases of CSs, surgery is the gold standard treatment modality;however in surgically unresectable cases or close to margins, radiotherapy plays a significant role in primary and adjuvant treatment. Based on the position of the tumor in head and neck and extremely closeness of the tumor to vital organs as optic nerve, chiasm and brain, image guided-intensity modulated radiation therapy (IG-IMRT) becomes very effective and reliable modalities and may be a favorable treatment alternative.
文摘BACKGROUND Neoadjuvant chemoradiotherapy(NACRT)has not been accepted as a general therapy for gastric cancer because of its localized effect and toxicity for radiosensitive organs.However,if radiation therapy could compensate for the limited or inadequate treatment choices available for elderly patients and/or those at high risk,the available therapeutic options for advanced gastric cancer might increase.From this perspective,we present our experiences of five patients with advanced gastric cancer in whom we used NACRT therapy with interesting results.CASE SUMMARY We admitted five patients with clinical Stage III gastric cancer and bulky lymph node metastasis or adjacent organ invasion at the time of diagnosis.A total of 50 Gy of preoperative intensity modulated radiation therapy was delivered to the patients in doses of 2.0 Gy/d,together with a regimen of concomitant chemotherapy comprising two courses of oral tegafur/gimeracil/oteracil(S-1;65 mg/m2 per day)for three consecutive weeks followed by two weeks of rest,starting at the same time as radiotherapy.All patients underwent no residual tumor resection and a pathological complete response of the primary tumors was achieved in two patients.The incidence of hematological toxicity was low,although the digestive toxicities of anorexia and diarrhea developed in three of the five patients,necessitating termination of radiation therapy at 30 Gy and S-1 at three weeks.However,even 30 Gy of irradiation and half the dose of S-1 resulted in sufficient downstaging,indicating that even a reduced amount of NACRT could confer considerable effects.CONCLUSION Slightly reduced NACRT might be useful and safe for patients with locally advanced gastric cancer.
文摘In order to explore a dose distribution verification procedure of intensity modulated radiation therapy （IMRT） for nasopharyngeal carcinoma （NPC） and establish its evaluation criteria, we performed 35 two-dimensional （2D） patient-specific IMRT verifications over the year i006. The percent of pixels passing 7 and the normalized agreement test （NAT） index were mainly used to represent the agreement between the measured and computed dose distributions with three criteria （2%/2 mm, 3%/3 mm and 5%/3 mm） as recommended in the literature. The results were that all cases passed through verifications with three criteria except that the NAT index of one case was beyond the limitation, and the three tolerance levels of 2%/2mm, 3%/3 mm and 5%/3 mm produced similar clinical verification results but led to different percent of pixels passing Y and NAT index. Our data showed that the percent of pixels passing y and the NAT index were complementary to evaluate future IMRT verifications as two significant metrics. Due to the influence of the noise and the trait of the software, we considered an IMRT plan as acceptable in case of the percent ofpixels passing y 〉95% and the NAT index 〈5 with the 5%/3 mm criteria for IMRT patient-specific quality assurance （QA）.
文摘We developed the first non-commercial treatment planning system for volumetric modulated arc therapy(VMAT) in the United States. Because VMAT involves multi-parameter modulations, it is imperative to develop a comprehensive, rigorous and yet, practical procedure for routine patient-specific quality assurance(QA). In this paper, we presented our own approach as being currently implemented in our institution.Our patient-specific QA procedure involves multi-levels: pre-treatment QA,on-treatment QA, and posttreatment QA. The pre-treatment QA focuses on dosimetry verification, which is done with the commercial Map CHECK in Map PHAN mounted on an isocentric mounting fixture(IMF). This method is also referred to the fixed-gantry technique,i.e., the beams always remain perpendicular to the detector plane. The on-treatment QA involves in vivo optically stimulated luminescent dosimetry(OSLD).Prior to the treatment, two nano Dot TM OSLD dosimeters are placed on the patient abdomen under 1 cm bolus at the isocenter location. The irradiated dosimeters are then read by a nano Dot TM reader and the average reading of the two is calculated. The post-treatment QA involves the analysis of the Dyna Log and DLog files. The Dyna Log is a treatment log file that contains the planned and actual leaf positions at a given gantry angle. The DLog is a treatment log file that contains the planned segmented treatment table(STT) and the corresponding segment boundary samples, i.e., the actual delivered MU and gantry angle increment at each control point.
基金supported in part by the National Natural Science Foundation of China(92259202)the Guangzhou Municipal Health Commission(2023P-GX02)+2 种基金the Science and Technology Projects in Guangzhou(2024B01J1301)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University Clinical Research 5010 Program(2024001)the Cancer Innovative Research Program of Sun Yat-sen University Cancer Center(CIRP-SYSUCC-0010).
文摘1.Introduction Nasopharyngeal carcinoma(NPC)has an imbalanced geographical and ethnic distribution,with notably high incidence rates in Southeastern Asia and China.China accounted for 42.4%of the newly diagnosed cases worldwide in 2022.1NPC is sensitive to irradiation,and radiotherapy is the mainstay curative treatment modality.2The widespread use of intensity-modulated radiation therapy(IMRT)and image-guided radiotherapy(IGRT)has achieved great advances in survival outcomes and toxicity profiles among NPC patients.1In radiotherapy of NPC,the tumor’s proximity to critical structures demands accuracy in tumor delineation in order to avoid radiation-induced toxicities.However,tumor target delineation for radiotherapy of NPC is labor-intensive and radiation oncologists’proficiency varied considerably.3In recent years,the advent of big data analytics and artificial intelligence(AI)has opened up new avenues for improving the precision and efficacy of radiotherapy and individualized treatment in NPC management.3-6In this article,we explored how big data,AI-assisted delineation,radiotherapy planning,and adaptive radiotherapy(ART)are transforming clinical decision-making in NPC treatment.We also provided an outlook on the historical development of AI and big data,their current dominance in oncological radiotherapy,and their projected impact on future clinical practice(Figure 1).
文摘With the continuous development of science and technolog ies in China,radiotherapy technology in medical field has been very significant ly developing,and intensity modulated radiation therapy(IMRT)technology has been the most widely used.This paper first introduces the components and types of two-dimensional matrix detector,two-dimensional ionization chamber matrix detector and two-dimensional semiconductor matrix detector,then analyzes the dosimetric characteristics of the two-dimensional matrix detector.In the end,the various applications of the two-dimensional matrix detector are analyzed and discussed in detail.The paper aims to promote the two-dimensional matrix detector’s development in the field of radiotherapy in China.
文摘Radiotherapy plays a critical role in the treatment of oral cavity squamous cell carcinoma as monotherapy in early stage cancer or combined with surgery and/or chemotherapy in advances ones.Recent developments in the imaging of cancer and radiation technology have allowed developing more precise delivery of treatment with recent data demonstrating improvement in survival and lessening of adverse toxics effects of radiation.This review will focus in the recent advances and current state-of-the-art in radiation oncology both external beam radiotherapy and brachytherapy.As complexity of cancer treatments increases a close coordination between head-neck surgeons and radiation oncologist is needed due to a significant proportion of patients will be treated with combined modality therapy.
文摘Background: For image-guided radiotherapy(IGRT) of prostate cancer, the current standard is online image guidance which can effectively correct setup errors and inter-fraction rigid organ motion. However, planning margins are still necessary for deformation and intra-fraction motion. Objective: This paper aims to investigate an adaptive planning technique incorporating offline dose feedback to manage interfraction motion and residuals from online corrections. Methods:Repeated CT scans from 28 patients were studied. Online IG was simulated by matching center-of-mass of prostate. A seven-beam IMRT plan with zero margins was designed for each patient. Dose distribution at each fraction was evaluated based on actual target and OARs from that fraction. Cumulative dose was calculated using deformable registration and compared to initial plan. If deviation exceeded pre-defined 2% threshold in prostate D99 an adaptive planning technique called dose compensation was invoked, in which cumulative dose was fed back to the planning system and dose deficit was made up through boost radiation in future fractions through IMRT. Results: If 2% under-dose was allowed at the end of course, then 11 patients failed. If the same criteria was assessed at the end of each week(every 5 fractions), then 14 patients failed. The average dose deficit for these 14 patients was4.4%. They improved to 2% after weekly compensation. 10(out of 14) patients passed criterion after weekly dose compensation; 3 failed marginally; 1 failed significantly(10% deficit). A more aggressive compensation frequency(every 3 fractions) could reduce the dose deficit to the acceptable level for this patient. The doses to OARs were not significantly different from online IG only without dose compensation.Conclusion: We demonstrated an offline dose compensation technique in prostate IGRT which can effectively account for residual uncertainties uncorrectable in online IG. Dose compensation allows further margin reduction and critical organs sparing.
